/* Global CSS Variables & Light Theme (Default) */
:root {
    --bg-color: #e2e8f0;
    --bg-card: rgba(255, 255, 255, 0.75);
    --bg-card-solid: #ffffff;
    --border-color: rgba(15, 23, 42, 0.08);
    --border-hover: rgba(15, 23, 42, 0.16);
    
    --pink: #d91b5c;
    --pink-rgb: 217, 27, 92;
    --pink-dark: rgba(217, 27, 92, 0.08);
    
    --green: #059669;
    --green-rgb: 5, 150, 105;
    --green-dark: rgba(5, 150, 105, 0.08);
    
    --cyan: #0891b2;
    --cyan-rgb: 8, 145, 178;
    --cyan-dark: rgba(8, 145, 178, 0.08);
    
    --purple: #7c3aed;
    --purple-glow: rgba(124, 58, 237, 0.15);

    --amber: #d97706;
    --amber-rgb: 217, 119, 6;
    --orange: #ea580c;
    --orange-rgb: 234, 88, 12;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #526178;
    
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    
    --font-sans: 'Figtree', sans-serif;
    --font-mono: 'Figtree', sans-serif;

    /* Theme Dynamic Canvas Color Elements */
    --canvas-bg: rgba(255, 255, 255, 0.65);
    --grid-stroke: rgba(15, 23, 42, 0.05);
    --circum-stroke: rgba(124, 58, 237, 0.35);
    --svg-text-outline: #ffffff;

    --purple-stop: rgba(124, 58, 237, 0.12);
    --purple-stop-hover: rgba(124, 58, 237, 0.20);
    --cyan-stop: rgba(8, 145, 178, 0.12);

    --pink-arc-bg: rgba(217, 27, 92, 0.06);
    --green-arc-bg: rgba(5, 150, 105, 0.06);
    --cyan-arc-bg: rgba(8, 145, 178, 0.06);

    --side-label-bg: #ffffff;
    --side-label-stroke: rgba(15, 23, 42, 0.2);
    --handle-outer-fill: rgba(255, 255, 255, 0.85);
    --formula-color: var(--text-secondary);
    --formula-bg: rgba(0, 0, 0, 0.04);
    --logo-bg: linear-gradient(90deg, #0f172a, #334155);

    /* Dynamic element variables */
    --triangle-stroke: #7c3aed;
    --slider-bg: rgba(15, 23, 42, 0.08);
    --slider-border: rgba(15, 23, 42, 0.12);
    --slider-knob: #ffffff;
    --btn-bg: rgba(15, 23, 42, 0.04);
    --btn-border: var(--border-color);
    --btn-hover-bg: rgba(15, 23, 42, 0.08);
    --btn-hover-border: rgba(15, 23, 42, 0.2);

    --bar-container-bg: rgba(15, 23, 42, 0.05);
    --bar-container-border: var(--border-color);
    --detail-row-bg: rgba(15, 23, 42, 0.02);
    --detail-row-hover-bg: rgba(15, 23, 42, 0.05);
    --meter-container-bg: rgba(15, 23, 42, 0.05);
    --meter-container-border: rgba(15, 23, 42, 0.03);
}
/* Dark Mode Overrides */
body.dark-mode {
    --bg-color: #070a13;
    --bg-card: rgba(15, 22, 42, 0.65);
    --bg-card-solid: #0f162a;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(255, 255, 255, 0.18);
    
    --pink: #ff4d7a;
    --pink-rgb: 255, 77, 122;
    --pink-dark: rgba(255, 77, 122, 0.15);
    
    --green: #34d399;
    --green-rgb: 52, 211, 153;
    --green-dark: rgba(52, 211, 153, 0.15);
    
    --cyan: #22d3ee;
    --cyan-rgb: 34, 211, 238;
    --cyan-dark: rgba(34, 211, 238, 0.15);
    
    --purple: #c084fc;
    --purple-glow: rgba(192, 132, 252, 0.35);

    --amber: #fbbf24;
    --amber-rgb: 251, 191, 36;
    --orange: #fb923c;
    --orange-rgb: 251, 146, 60;

    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;

    --canvas-bg: rgba(3, 7, 18, 0.4);
    --grid-stroke: rgba(148, 163, 184, 0.05);
    --circum-stroke: rgba(168, 85, 247, 0.25);
    --svg-text-outline: #070a13;

    --purple-stop: rgba(168, 85, 247, 0.18);
    --purple-stop-hover: rgba(168, 85, 247, 0.28);
    --cyan-stop: rgba(34, 211, 238, 0.18);

    --pink-arc-bg: rgba(255, 77, 122, 0.08);
    --green-arc-bg: rgba(52, 211, 153, 0.08);
    --cyan-arc-bg: rgba(34, 211, 238, 0.08);

    --side-label-bg: #070a13;
    --side-label-stroke: rgba(255, 255, 255, 0.25);
    --handle-outer-fill: rgba(7, 10, 19, 0.6);
    --formula-color: var(--text-secondary);
    --formula-bg: rgba(0, 0, 0, 0.25);
    --logo-bg: linear-gradient(90deg, #ffffff, #cbd5e1);

    /* Dynamic element variables */
    --triangle-stroke: #a855f7;
    --slider-bg: rgba(255, 255, 255, 0.1);
    --slider-border: rgba(255, 255, 255, 0.05);
    --slider-knob: #ffffff;
    --btn-bg: rgba(255, 255, 255, 0.03);
    --btn-border: var(--border-color);
    --btn-hover-bg: rgba(255, 255, 255, 0.08);
    --btn-hover-border: rgba(255, 255, 255, 0.2);

    --bar-container-bg: rgba(0, 0, 0, 0.25);
    --bar-container-border: rgba(255, 255, 255, 0.05);
    --detail-row-bg: rgba(255, 255, 255, 0.02);
    --detail-row-hover-bg: rgba(255, 255, 255, 0.04);
    --meter-container-bg: rgba(255, 255, 255, 0.05);
    --meter-container-border: rgba(255, 255, 255, 0.03);
}

/* Persian Font Override */
:root:lang(fa),
html[lang="fa"] {
    --font-sans: 'Vazirmatn', 'Figtree', sans-serif;
    --font-mono: 'Vazirmatn', 'Figtree', sans-serif;
}

/* Base Styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-sans);
    height: 100vh;
    padding: 1rem;
    overflow: hidden;
    position: relative;
    display: flex;
    flex-direction: column;
}

body.modal-open {
    overflow: hidden;
}

[hidden] {
    display: none !important;
}

.is-hidden {
    display: none !important;
}

/* Colorful Gradient Background Blobs for Glassmorphism Context */
.glow-bg {
    position: fixed;
    top: 20%;
    left: 10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(168, 85, 247, 0.12) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
    z-index: -1;
    animation: floating-glow 8s ease-in-out infinite alternate;
}

body::after {
    content: '';
    position: fixed;
    bottom: 10%;
    right: 15%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(34, 211, 238, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
    z-index: -1;
    animation: floating-glow 10s ease-in-out infinite alternate-reverse;
}

@keyframes floating-glow {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(5%, 8%) scale(1.1); }
}

/* Typography & Links */
h1, h2, h3, h4 {
    font-weight: 600;
    letter-spacing: -0.02em;
}

.fira-font {
    font-family: var(--font-mono);
}

.pink-text { color: var(--pink) !important; fill: var(--pink) !important; }
.green-text { color: var(--green) !important; fill: var(--green) !important; }
.cyan-text { color: var(--cyan) !important; fill: var(--cyan) !important; }
.purple-text { color: var(--purple) !important; fill: var(--purple) !important; }
.text-white { color: var(--text-primary) !important; fill: var(--text-primary) !important; }

/* Header Component: compact tool bar for iframe embedding */
.app-header {
    max-width: 1280px;
    width: 100%;
    margin: 0 auto 1.25rem auto;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.6rem 1rem;
    background: var(--bg-card);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border: 1.5px solid var(--border-color);
    border-radius: 14px;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-shrink: 0;
}

.logo-icon {
    font-size: 1.3rem;
    background: linear-gradient(135deg, var(--pink), var(--purple), var(--cyan));
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: logo-spin 6s linear infinite;
}

@keyframes logo-spin {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.logo-area h1 {
    font-size: 1.3rem;
    font-weight: 800;
    letter-spacing: 0.05em;
    background: var(--logo-bg);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 400;
    line-height: 1.4;
    flex: 1;
    margin: 0;
}

.header-tools {
    display: flex;
    gap: 0.5rem;
    flex-shrink: 0;
    margin-inline-start: auto;
}

/* Dashboard Cards System - Glassmorphism */
.card {
    background-color: var(--bg-card);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border: 1.5px solid var(--border-color);
    border-radius: 20px;
    padding: 1.5rem;
    transition: border-color var(--transition-normal);
}

.card:hover {
    border-color: var(--border-hover);
}

/* Layout Framework */
.app-layout {
    max-width: 1280px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    grid-template-rows: auto 1fr;
    gap: 1.5rem;
    flex: 1;
    min-height: 0;
    overflow: hidden;
    width: 100%;
}

/*
 * Normal state:
 *   Col 1 row 1: board (non-scrolling)
 *   Col 1 row 2: presets + display settings (scrollable)
 *   Col 2 rows 1-2: sidebar (scrollable, full height beside board AND presets)
 */
.app-layout > .canvas-container {
    grid-column: 1;
    grid-row: 1;
}

.app-layout > .left-column {
    grid-column: 1;
    grid-row: 2;
}

.app-layout > .sidebar {
    grid-column: 2;
    grid-row: 1 / 3;   /* spans beside board AND presets */
}

/*
 * Maximized state:
 *   Board spans both columns row 1 (width-capped to prevent fill)
 *   Col 1 row 2: presets + display settings (scrollable)
 *   Col 2 row 2: sidebar (scrollable)
 *   Both columns remain visible.
 */
.app-layout.board-maximized > .canvas-container {
    grid-column: 1 / -1;
    grid-row: 1;
}

.app-layout.board-maximized > .sidebar {
    grid-row: 2;         /* drop back to row 2 only */
}

/* Cap the board height in maximized mode so row-2 panels stay visible */
.app-layout.board-maximized .canvas-wrapper {
    max-width: calc(55vh * 1.5);
    margin: 0 auto;
}

@media (max-width: 1024px) {
    body {
        height: auto;
        overflow: auto;
    }

    .app-layout {
        grid-template-columns: 1fr;
        grid-template-rows: auto;
        overflow: visible;
        flex: none;
    }

    .app-layout > .canvas-container,
    .app-layout > .left-column,
    .app-layout > .sidebar,
    .app-layout.board-maximized > .canvas-container,
    .app-layout.board-maximized > .sidebar {
        grid-column: 1;
        grid-row: auto;
    }

    .app-layout.board-maximized .canvas-wrapper {
        max-width: 100%;
        margin: 0;
    }

    .sidebar {
        overflow-y: visible;
    }

    .left-column {
        overflow: visible;
    }
}

/* Left Column: board + presets + display settings */
.left-column {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    overflow-y: auto;
    padding-inline-end: 0.25rem;
    scrollbar-width: thin;
    scrollbar-color: var(--border-hover) transparent;
}

.left-column::-webkit-scrollbar {
    width: 4px;
}

.left-column::-webkit-scrollbar-track {
    background: transparent;
}

.left-column::-webkit-scrollbar-thumb {
    background-color: var(--border-hover);
    border-radius: 999px;
}

.canvas-container {
    overflow: hidden;
    position: relative;
}

/* Board maximize/restore button (overlaid on canvas top-right corner) */
.btn-board-maximize {
    position: absolute;
    inset-block-start: 8px;
    inset-inline-end: 8px;
    z-index: 10;
    width: 28px;
    height: 28px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background: var(--bg-card);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
    padding: 0;
    opacity: 0.7;
}

.btn-board-maximize:hover {
    border-color: var(--border-hover);
    color: var(--text-primary);
    background: var(--btn-hover-bg);
    opacity: 1;
}

.btn-board-maximize .icon-board-compress { display: none; }
.app-layout.board-maximized .btn-board-maximize .icon-board-expand  { display: none; }
.app-layout.board-maximized .btn-board-maximize .icon-board-compress { display: flex; }




/* SVG Canvas styling */
.canvas-wrapper {
    background-color: var(--canvas-bg);
    border-radius: 12px;
    border: 1px solid var(--border-color);
    overflow: hidden;
    position: relative;
    width: 100%;
    aspect-ratio: 3 / 2; /* Follows viewBox="0 0 600 400" */
    touch-action: none; /* Prevents scrolling when dragging on touch devices */
}

#board {
    display: block;
    width: 100%;
    height: 100%;
    user-select: none;
}

/* Grid & Helpers in Canvas */
.grid-lines line {
    stroke: var(--grid-stroke);
    stroke-width: 1;
}

.helper-line {
    stroke: rgba(168, 85, 247, 0.15);
    stroke-width: 1.5;
    stroke-dasharray: 4, 4;
}

.circumcircle-line {
    fill: none;
    stroke: var(--circum-stroke);
    stroke-width: 2;
    stroke-dasharray: 6, 4;
}

.circumcenter-dot {
    fill: var(--purple);
    stroke: var(--text-primary);
    stroke-width: 1;
    opacity: 0.8;
}

/* Vector styling */
.angle-arc {
    stroke-linecap: round;
    stroke-linejoin: round;
    opacity: 0.85;
}

.pink-arc { stroke: var(--pink); fill: var(--pink-arc-bg); stroke-width: 2; }
.green-arc { stroke: var(--green); fill: var(--green-arc-bg); stroke-width: 2; }
.cyan-arc { stroke: var(--cyan); fill: var(--cyan-arc-bg); stroke-width: 2; }

/* Side Labels on SVG */
.side-label-group {
    transition: opacity var(--transition-fast);
}

.side-label-group .label-bg {
    fill: var(--side-label-bg);
    stroke: var(--side-label-stroke);
    stroke-width: 1.5;
    opacity: 1;
}

.side-label-group .label-text {
    font-family: var(--font-sans);
    font-size: 11px;
    font-weight: 600;
    fill: var(--text-primary);
    text-anchor: middle;
    dominant-baseline: central;
}

.angle-label-text {
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 700;
    text-anchor: middle;
    pointer-events: none;
    paint-order: stroke fill;
    stroke: var(--svg-text-outline);
    stroke-width: 2.5px;
    stroke-linejoin: round;
}

html[lang="fa"] .angle-label-text,
html[lang="fa"] .bar-value,
html[lang="fa"] #val-angle-a,
html[lang="fa"] #val-angle-b,
html[lang="fa"] #val-angle-c,
html[lang="fa"] #val-angle-sum,
html[lang="fa"] [data-tooltip-slot^="angle-"],
html[lang="fa"] .numeric-ltr {
    direction: ltr;
    unicode-bidi: isolate;
}

html[lang="fa"] [data-tooltip-slot^="angle-"],
html[lang="fa"] .numeric-ltr {
    display: inline-block;
}

/* Interactive SVG Handles */

.handle-pulse-ring {
    fill: none;
    stroke-width: 1.5;
    opacity: 0;
    transform-origin: 0px 0px;
    transition: opacity var(--transition-fast);
}

.handle:hover .handle-pulse-ring {
    opacity: 0.45;
    animation: ring-pulse 1.6s cubic-bezier(0.16, 1, 0.3, 1) infinite;
}

@keyframes ring-pulse {
    0% { transform: scale(0.5); opacity: 0.8; }
    100% { transform: scale(2.0); opacity: 0; }
}

.handle-outer {
    fill: var(--handle-outer-fill);
    stroke-width: 2.5;
    transition: stroke-width var(--transition-fast), r var(--transition-fast);
}

.handle:hover .handle-outer {
    r: 13.5;
    stroke-width: 3.5;
}

.color-pink { stroke: var(--pink); }
.color-green { stroke: var(--green); }
.color-cyan { stroke: var(--cyan); }

.handle-inner.color-pink { fill: var(--pink); }
.handle-inner.color-green { fill: var(--green); }
.handle-inner.color-cyan { fill: var(--cyan); }

.handle-inner {
    transition: r var(--transition-fast);
}

.handle:hover .handle-inner {
    r: 7.5;
}

.handle-letter {
    font-family: var(--font-sans);
    font-weight: 800;
    font-size: 14px;
    pointer-events: none;
    paint-order: stroke fill;
    stroke: var(--svg-text-outline);
    stroke-width: 2.5px;
    stroke-linejoin: round;
}

/* Display Settings card (no extra chrome; uses .card styles) */

.toggles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 1rem;
}

/* Board Tooltip */
.svg-tooltip {
    position: fixed;
    background: var(--bg-card-solid);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 0.5rem 0.75rem;
    font-family: var(--font-sans);
    font-size: 0.78rem;
    color: var(--text-primary);
    pointer-events: none;
    z-index: 150;
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
    max-width: 210px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
    opacity: 0;
    transition: opacity 0.12s ease;
    line-height: 1.45;
}

.svg-tooltip.visible {
    opacity: 1;
}

body.dark-mode .svg-tooltip {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
}

.svg-tooltip .katex {
    font-size: 1em;
    vertical-align: middle;
}

/* KaTeX: Always LTR direction for all math formulas */
.katex {
    direction: ltr !important;
    unicode-bidi: embed !important;
}

.katex * {
    direction: ltr !important;
}

/* KaTeX: Use default KaTeX fonts for all languages */
.katex,
.katex * {
    font-family: KaTeX_Main, "Times New Roman", serif !important;
}

/* Persian words and localized digits inside formulas use Vazirmatn.
   Latin variables, operators, and other math glyphs keep KaTeX fonts. */
html[lang="fa"] .katex .persian-math-text {
    font-family: 'Vazirmatn', sans-serif !important;
    font-size: 0.85em;
    font-style: normal;
    direction: rtl !important;
    unicode-bidi: isolate !important;
}

.tip-title {
    font-weight: 700;
    font-size: 0.82rem;
}

.tip-detail {
    color: var(--text-secondary);
    font-size: 0.74rem;
}

.tip-value {
    font-family: var(--font-mono);
    font-size: 0.74rem;
    color: var(--text-muted);
}

/* Settings Modal */
.settings-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-normal);
}

.settings-overlay.open {
    opacity: 1;
    pointer-events: all;
}

.settings-panel {
    background: var(--bg-card-solid);
    border: 1.5px solid var(--border-color);
    border-radius: 20px;
    padding: 1.5rem;
    width: min(560px, 92vw);
    max-height: 85vh;
    overflow-y: auto;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.45);
    transform: scale(0.96) translateY(8px);
    transition: transform var(--transition-normal);
}

.settings-overlay.open .settings-panel {
    transform: scale(1) translateY(0);
}

body.dark-mode .settings-panel {
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.14);
}

.settings-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.settings-header h2 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.settings-section {
    margin-bottom: 1.25rem;
}

.settings-section:last-of-type {
    margin-bottom: 0;
}

.settings-section-title {
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 0.6rem;
}

.settings-toggles {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.1rem 1.5rem;
}

.settings-presets-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
}

.settings-presets-buttons .btn {
    padding: 0.6rem 0.75rem;
    font-size: 0.8rem;
}

.settings-url-hint {
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.settings-url-label {
    display: block;
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.settings-url-code {
    display: block;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--formula-color);
    background: var(--formula-bg);
    padding: 0.6rem 0.75rem;
    border-radius: 8px;
    word-break: break-all;
    line-height: 1.6;
    user-select: all;
}

.toggle-switch {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    user-select: none;
}

.toggle-switch input {
    display: none;
}

.slider {
    position: relative;
    width: 38px;
    height: 20px;
    background-color: var(--slider-bg);
    border-radius: 999px;
    transition: var(--transition-fast);
    border: 1px solid var(--slider-border);
}

.slider::after {
    content: '';
    position: absolute;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background-color: var(--slider-knob);
    top: 2px;
    left: 2px;
    transition: transform var(--transition-fast);
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.toggle-switch input:checked + .slider {
    background-color: var(--purple);
}

.toggle-switch input:checked + .slider::after {
    transform: translateX(18px);
}

.toggle-label {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.toggle-switch:hover .toggle-label {
    color: var(--text-primary);
}

/* SIDEBAR: Details & Analytics Stack */
.sidebar {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    overflow-y: auto;
    padding-inline-end: 0.25rem;
    scrollbar-width: thin;
    scrollbar-color: var(--border-hover) transparent;
}

.sidebar::-webkit-scrollbar {
    width: 4px;
}

.sidebar::-webkit-scrollbar-track {
    background: transparent;
}

.sidebar::-webkit-scrollbar-thumb {
    background-color: var(--border-hover);
    border-radius: 999px;
}

/* Preset buttons layout */

.presets-buttons {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.5rem;
}

.btn {
    border: 1px solid var(--btn-border);
    background: var(--btn-bg);
    color: var(--text-secondary);
    padding: 0.5rem 0.75rem;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    transition: var(--transition-fast);
}

.btn:hover {
    border-color: var(--btn-hover-border);
    background: var(--btn-hover-bg);
    color: var(--text-primary);
}

.btn-icon {
    font-size: 0.9rem;
    line-height: 1;
}

/* Card Headers Style */
.card-header-simple {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    transition: margin-bottom 0.3s ease;
}

.card-header-simple h3 {
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    font-weight: 600;
}

/* Collapsible Panel System */
.collapsible-header {
    cursor: pointer;
    user-select: none;
}

.collapsible-card[data-collapsed="true"] .card-header-simple {
    margin-bottom: 0;
}

.collapsible-body {
    overflow: hidden;
    max-height: 2000px;
}

.collapsible-card[data-collapsed="true"] .collapsible-body {
    max-height: 0;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.collapse-toggle {
    width: 28px;
    height: 28px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
    padding: 0;
}

.collapse-toggle:hover {
    border-color: var(--border-hover);
    color: var(--text-primary);
    background: var(--btn-hover-bg);
}

.chevron-icon {
    transition: transform 0.25s ease;
}

.collapsible-card[data-collapsed="true"] .chevron-icon {
    transform: rotate(-90deg);
}

/* Help Button */
.btn-help {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-muted);
    font-family: var(--font-sans);
    font-size: 0.85rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
    padding: 0;
}

.btn-help:hover {
    border-color: var(--purple);
    color: var(--purple);
    background: rgba(192, 132, 252, 0.08);
}

/* Help Modal */
.help-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-normal);
}

.help-overlay.open {
    opacity: 1;
    pointer-events: all;
}

.help-panel {
    background: var(--bg-card-solid);
    border: 1.5px solid var(--border-color);
    border-radius: 20px;
    padding: 1.5rem;
    width: min(480px, 92vw);
    max-height: 85vh;
    overflow-y: auto;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.45);
    transform: scale(0.96) translateY(8px);
    transition: transform var(--transition-normal);
}

.help-overlay.open .help-panel {
    transform: scale(1) translateY(0);
}

body.dark-mode .help-panel {
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.14);
}

.help-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.help-header h2 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.help-body {
    font-size: 0.92rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

.help-body p {
    margin-bottom: 0.75rem;
}

.help-formula-line {
    text-align: center;
    margin: 1rem 0;
    overflow-x: auto;
}

.help-body p:last-child {
    margin-bottom: 0;
}

.help-body strong {
    color: var(--text-primary);
    font-weight: 600;
}


/* Classification styles */
.classification-details {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 0.75rem;
}

.class-item {
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
}

.class-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.class-item strong {
    font-size: 1.1rem;
    font-weight: 700;
}

.class-description {
    font-size: 0.85rem;
    line-height: 1.4;
    color: var(--text-secondary);
    padding-top: 0.5rem;
    border-top: 1px solid var(--border-color);
}

/* Sum of Angles Bar Stack styling */
.math-formula {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.stacked-bar-wrapper {
    margin-bottom: 1.25rem;
}

.stacked-bar-container {
    display: flex;
    height: 32px;
    border-radius: 8px;
    overflow: hidden;
    background-color: var(--bar-container-bg);
    border: 1px solid var(--bar-container-border);
    margin-bottom: 0.4rem;
}

.bar-segment {
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-weight: 700;
    font-size: 0.75rem;
    font-family: var(--font-sans);
    transition: width 0.1s ease;
    overflow: hidden;
    position: relative;
    text-shadow: 0 1px 3px rgba(0,0,0,0.6);
    width: 33.333%;
}

.bar-pink {
    background-color: var(--pink);
    background-image: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
    box-shadow: inset 0 1px rgba(255,255,255,0.2);
}

.bar-green {
    background-color: var(--green);
    background-image: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
    box-shadow: inset 0 1px rgba(255,255,255,0.2);
}

.bar-cyan {
    background-color: var(--cyan);
    background-image: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
    box-shadow: inset 0 1px rgba(255,255,255,0.2);
}

.bar-value {
    white-space: nowrap;
    pointer-events: none;
}

/* Angle Details list */
.angle-details-list {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.angle-detail-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.55rem 0.75rem;
    border-radius: 10px;
    background-color: var(--detail-row-bg);
    border-inline-start: 4px solid transparent;
    transition: background-color var(--transition-fast);
}

/* Per-color tinted backgrounds */
.angle-detail-row.green-border {
    border-inline-start-color: var(--green);
    background-color: rgba(var(--green-rgb), 0.06);
}
.angle-detail-row.pink-border {
    border-inline-start-color: var(--pink);
    background-color: rgba(var(--pink-rgb), 0.06);
}
.angle-detail-row.cyan-border {
    border-inline-start-color: var(--cyan);
    background-color: rgba(var(--cyan-rgb), 0.06);
}

.angle-detail-row.green-border:hover { background-color: rgba(var(--green-rgb), 0.1); }
.angle-detail-row.pink-border:hover  { background-color: rgba(var(--pink-rgb), 0.1); }
.angle-detail-row.cyan-border:hover  { background-color: rgba(var(--cyan-rgb), 0.1); }

.total-row {
    border-inline-start-color: var(--purple);
    background-color: rgba(168, 85, 247, 0.08);
    margin-top: 0.25rem;
}
.total-row:hover {
    background-color: rgba(168, 85, 247, 0.12);
}

/* Shared hover effect for all colored panel rows */
.panel-row {
    transition: background-color var(--transition-fast);
}
.panel-row.green-border:hover  { background-color: rgba(var(--green-rgb), 0.14); }
.panel-row.pink-border:hover   { background-color: rgba(var(--pink-rgb), 0.14); }
.panel-row.cyan-border:hover   { background-color: rgba(var(--cyan-rgb), 0.14); }
.panel-row.purple-border:hover { background-color: var(--purple-stop-hover); }

.angle-name {
    font-size: 0.85rem;
    color: var(--text-secondary);
    flex-grow: 1;
}

.angle-detail-row strong {
    font-size: 1rem;
    font-weight: 700;
}

/* Sides & Perimeter widgets */
.sides-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
    margin-bottom: 1.25rem;
}

.side-item-box {
    border-radius: 10px;
    padding: 0.75rem;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    border: 1px solid transparent;
}

.side-hdr {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.side-val {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 700;
}

.pink-bg-dark {
    background-color: var(--pink-dark);
    border-color: rgba(var(--pink-rgb), 0.18);
}
.green-bg-dark {
    background-color: var(--green-dark);
    border-color: rgba(var(--green-rgb), 0.18);
}
.cyan-bg-dark {
    background-color: var(--cyan-dark);
    border-color: rgba(var(--cyan-rgb), 0.18);
}

/* Perimeter gauge styling */
.perimeter-container {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.perimeter-header {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.perimeter-val {
    font-family: var(--font-mono);
    font-weight: 600;
}

.meter-bar-container {
    height: 8px;
    background-color: var(--meter-container-bg);
    border-radius: 999px;
    overflow: hidden;
    border: 1px solid var(--meter-container-border);
}

.meter-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--pink), var(--purple), var(--cyan));
    border-radius: 999px;
    transition: width 0.1s ease;
    width: 0;
}

/* Area panel */
.area-layout {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding-top: 0.35rem;
}

.area-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.65rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
}

.area-row.green-border {
    border-inline-start-color: var(--green);
    background-color: rgba(var(--green-rgb), 0.08);
}
.area-row.pink-border {
    border-inline-start-color: var(--pink);
    background-color: rgba(var(--pink-rgb), 0.08);
}
.area-row.cyan-border {
    border-inline-start-color: var(--cyan);
    background-color: rgba(var(--cyan-rgb), 0.08);
}
.area-row.purple-border {
    border-inline-start-color: var(--purple);
    background-color: var(--purple-stop);
}
.area-row.purple-border .area-row-val {
    color: var(--purple);
}

.area-formula-cell {
    flex: 1;
    min-width: 0;
    line-height: 1;
}

.area-row-val {
    font-size: 1rem;
    font-weight: 700;
    flex-shrink: 0;
}

.area-full-formula {
    padding-top: 0.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.35rem;
}

.area-semi-row {
    display: flex;
    align-items: baseline;
    gap: 0.35rem;
}

.area-semi-val {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--formula-color);
    font-weight: 600;
}

.area-semi-hint {
    font-size: 0.7rem;
    color: var(--text-muted);
}

/* Law of Sines panel */
.sines-layout {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding-top: 0.35rem;
}

.sines-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.65rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
}

.sines-row.green-border {
    border-inline-start-color: var(--green);
    background-color: rgba(var(--green-rgb), 0.08);
}
.sines-row.pink-border {
    border-inline-start-color: var(--pink);
    background-color: rgba(var(--pink-rgb), 0.08);
}
.sines-row.cyan-border {
    border-inline-start-color: var(--cyan);
    background-color: rgba(var(--cyan-rgb), 0.08);
}

.sines-formula-cell {
    flex: 1;
    min-width: 0;
    line-height: 1;
}

.sines-row-val {
    font-size: 1rem;
    font-weight: 700;
    flex-shrink: 0;
}

.sines-full-formula {
    padding-top: 0.5rem;
    display: flex;
    justify-content: center;
}

.formula-katex-style {
    color: var(--formula-color);
    background: transparent;
    display: inline-block;
}

/* Footer Component */
.app-footer {
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-muted);
    border-top: 1px solid var(--border-color);
    margin-top: 1rem;
    padding: 0.75rem 0 0.25rem;
    flex-shrink: 0;
}

.footer-link {
    color: var(--purple);
    text-decoration: none;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: var(--cyan);
}

.btn-tool {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    background-color: var(--bg-card);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition-fast);
}

.btn-tool:hover {
    border-color: var(--border-hover);
    color: var(--text-primary);
    background-color: rgba(255, 255, 255, 0.08);
}

body.dark-mode .btn-tool:hover {
    background-color: rgba(0, 0, 0, 0.04);
}

.btn-tool svg {
    pointer-events: none;
    transition: transform var(--transition-fast);
}

.btn-tool:hover svg {
    transform: scale(1.1);
}

/* Theme Sun/Moon toggle visibility classes */
.btn-tool .icon-sun { display: block; }
.btn-tool .icon-moon { display: none; }

body.dark-mode .btn-tool .icon-sun { display: none; }
body.dark-mode .btn-tool .icon-moon { display: block; }

/* Fullscreen Expand/Compress toggle visibility classes */
.btn-tool .icon-expand { display: block; }
.btn-tool .icon-compress { display: none; }

body.fullscreen-mode .btn-tool .icon-expand { display: none; }
body.fullscreen-mode .btn-tool .icon-compress { display: block; }

/* Dynamic Triangle Grad stops */
#triangle-grad stop:nth-child(1) {
    stop-color: var(--purple-stop);
}
#triangle-grad stop:nth-child(2) {
    stop-color: var(--cyan-stop);
}

/* Dark mode overrides for glow backdrops */
body.dark-mode .glow-bg {
    background: radial-gradient(circle, rgba(124, 58, 237, 0.08) 0%, rgba(0, 0, 0, 0) 70%);
}
body.dark-mode::after {
    background: radial-gradient(circle, rgba(8, 145, 178, 0.06) 0%, rgba(0, 0, 0, 0) 70%);
}

/* ========== New Rules ========== */

/* Skip link for keyboard accessibility */
.skip-link {
    position: absolute;
    left: -9999px;
    top: 0;
    z-index: 999;
    padding: 0.5rem 1rem;
    background: var(--purple);
    color: #fff;
    border-radius: 0 0 8px 0;
    font-weight: 600;
    font-size: 0.9rem;
    text-decoration: none;
}

.skip-link:focus {
    left: 0;
}

/* Grabbing cursor during drag */
body.grabbing,
body.grabbing * {
    cursor: grabbing !important;
}

/* Snap-to-grid active indicator */
body.snap-active .canvas-wrapper {
    outline: 2px dashed var(--purple);
    outline-offset: -2px;
}

/* Card shadow in dark mode */
body.dark-mode .card {
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.06), 0 1px 4px rgba(0, 0, 0, 0.04);
}

/* Active preset button */
.btn-active {
    border-color: var(--purple) !important;
    background: var(--purple-glow) !important;
    color: var(--text-primary) !important;
    box-shadow: 0 0 8px var(--purple-glow);
}

/* Reset button: same style as other preset buttons, no overrides needed */

/* Classification text transition */
.classification-details strong,
.class-description p {
    transition: opacity var(--transition-normal);
}

/* Improve toggle touch target size */
.toggle-switch {
    min-height: 44px;
    padding: 4px 0;
}

/* Area footnote */
.area-footnote {
    font-size: 0.7rem;
    color: var(--text-muted);
    text-align: center;
    margin-top: 0.75rem;
    font-style: italic;
    opacity: 0.8;
}



/* Orthocenter dot */
.orthocenter-dot {
    fill: var(--green);
    stroke: var(--text-primary);
    stroke-width: 1;
    opacity: 0.9;
}

/* Incircle */
.incircle-line {
    fill: rgba(var(--orange-rgb), 0.05);
    stroke: var(--orange);
    stroke-width: 2;
    stroke-dasharray: 6, 4;
}

.incenter-dot {
    fill: var(--orange);
    stroke: var(--text-primary);
    stroke-width: 1;
    opacity: 0.9;
}

/* Altitudes panel: matrix layout */
.altitudes-layout {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    padding-top: 0.35rem;
}

.altitudes-header,
.altitudes-row {
    display: grid;
    grid-template-columns: 1.1rem 1fr 1fr 1fr;
    align-items: center;
    gap: 0.5rem;
    padding: 0 0.75rem;
}

.altitudes-header {
    padding-bottom: 0.1rem;
}

.alt-col-hdr {
    font-size: 0.68rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    text-align: center;
}

.altitudes-row {
    padding: 0.6rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
}

.altitudes-row.green-border {
    border-inline-start-color: var(--green);
    background-color: rgba(var(--green-rgb), 0.08);
}
.altitudes-row.pink-border {
    border-inline-start-color: var(--pink);
    background-color: rgba(var(--pink-rgb), 0.08);
}
.altitudes-row.cyan-border {
    border-inline-start-color: var(--cyan);
    background-color: rgba(var(--cyan-rgb), 0.08);
}

.alt-row-label {
    font-size: 0.8rem;
    font-weight: 700;
}

.alt-row-val {
    font-size: 0.88rem;
    font-weight: 700;
    text-align: center;
}

.altitudes-full-formula {
    padding-top: 0.5rem;
    display: flex;
    justify-content: center;
}

/* Law of Sines card: see .sines-layout rules above */

/* Circumscribed Circle panel */
.circum-layout {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding-top: 0.35rem;
}

.circum-r-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.65rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid var(--purple);
    background-color: var(--purple-stop);
    transition: background-color var(--transition-fast);
}
.circum-r-row:hover { background-color: var(--purple-stop-hover); }

.circum-formula-cell {
    flex: 1;
    min-width: 0;
    line-height: 1;
}

.circum-r-val {
    font-size: 1rem;
    font-weight: 700;
    flex-shrink: 0;
}

.circum-position-note {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.25rem 0.75rem;
    font-size: 0.82rem;
}

.circum-note-label {
    color: var(--text-muted);
    flex-shrink: 0;
}

.circum-position-text {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-secondary);
}


/* Inscribed Circle panel */
.incirc-layout {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    padding-top: 0.35rem;
}

.incirc-r-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.65rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid var(--orange);
    background-color: rgba(var(--orange-rgb), 0.08);
    margin-bottom: 0.2rem;
    transition: background-color var(--transition-fast);
}
.incirc-r-row:hover { background-color: rgba(var(--orange-rgb), 0.16); }

.incirc-formula-cell {
    flex: 1;
    min-width: 0;
    line-height: 1;
}

.incirc-r-val {
    font-size: 1rem;
    font-weight: 700;
    flex-shrink: 0;
    color: var(--orange);
}



/* Law of Cosines card */
.cosines-layout {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding-top: 0.35rem;
}

.cosines-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
    padding: 0.65rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
}

.cosines-row.green-border {
    border-inline-start-color: var(--green);
    background-color: rgba(var(--green-rgb), 0.08);
}
.cosines-row.pink-border {
    border-inline-start-color: var(--pink);
    background-color: rgba(var(--pink-rgb), 0.08);
}
.cosines-row.cyan-border {
    border-inline-start-color: var(--cyan);
    background-color: rgba(var(--cyan-rgb), 0.08);
}

.cosines-formula-cell {
    flex: 1;
    min-width: 0;
    line-height: 1;
}

.cosines-row-val {
    font-size: 1rem;
    font-weight: 700;
    flex-shrink: 0;
}

/* Altitude side-extension lines (dotted, when foot is outside the triangle) */
.alt-ext-line {
    stroke: rgba(168, 85, 247, 0.3);
    stroke-width: 1.5;
    stroke-dasharray: 5, 4;
    stroke-linecap: round;
}

/* Right-angle square marker at altitude feet */
.alt-foot-rect {
    fill: none;
    stroke: rgba(168, 85, 247, 0.55);
    stroke-width: 1.5;
    stroke-linejoin: miter;
}

/* Board metric badges (perimeter / area overlays on the canvas) */
.board-badge-bg {
    fill: rgba(255, 255, 255, 0.85);
    stroke: rgba(15, 23, 42, 0.15);
    stroke-width: 1;
}

body.dark-mode .board-badge-bg {
    fill: rgba(7, 10, 19, 0.72);
    stroke: rgba(255, 255, 255, 0.12);
}

.board-badge-text {
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 600;
    fill: var(--text-primary);
    dominant-baseline: central;
    text-anchor: middle;
    direction: ltr;
}

/* Responsive sides grid and presets */
@media (max-width: 480px) {
    .sides-grid {
        grid-template-columns: 1fr;
    }

    .presets-buttons {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .app-header .subtitle {
        display: none;
    }
}

/* ============================================================
   NEW CONSTRUCTION LINES - SVG canvas elements
   ============================================================ */

/* Median lines - solid, vertex-colored */
.median-line {
    stroke-width: 1.5;
    fill: none;
    opacity: 0.85;
    stroke-linecap: round;
}
.green-median { stroke: var(--green); }
.pink-median  { stroke: var(--pink); }
.cyan-median  { stroke: var(--cyan); }

/* Angle bisector lines - dashed, vertex-colored */
.anglebis-line {
    stroke-width: 1.5;
    stroke-dasharray: 5 3;
    fill: none;
    opacity: 0.85;
    stroke-linecap: round;
}
.green-anglebis { stroke: var(--green); }
.pink-anglebis  { stroke: var(--pink); }
.cyan-anglebis  { stroke: var(--cyan); }

/* Perpendicular bisector lines - dashed, purple */
.perpbis-line {
    stroke: var(--purple);
    stroke-width: 1.5;
    stroke-dasharray: 5 3;
    fill: none;
    opacity: 0.7;
    stroke-linecap: round;
}

/* Midpoint dots (shared by medians, perp bisectors, midlines) */
.midpoint-dot {
    fill: var(--text-muted);
    stroke: var(--text-primary);
    stroke-width: 1;
    opacity: 0.9;
}

/* Midline / midsegment lines - dashed, side color */
.midline-line {
    stroke-width: 2;
    fill: none;
    opacity: 0.9;
    stroke-dasharray: 6 4;
    stroke-linecap: round;
}
.green-midline { stroke: var(--green); }
.pink-midline  { stroke: var(--pink); }
.cyan-midline  { stroke: var(--cyan); }

/* Centroid dot */
.centroid-dot {
    fill: var(--amber);
    stroke: var(--text-primary);
    stroke-width: 1;
}

/* ============================================================
   MEDIANS PANEL
   ============================================================ */

.medians-layout {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    padding-top: 0.35rem;
}

.medians-header {
    display: grid;
    grid-template-columns: 2rem 1fr 1.2fr 1.2fr;
    gap: 0.5rem;
    padding: 0 0.75rem 0.25rem;
    align-items: center;
}

.med-col-hdr {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--text-muted);
    text-align: center;
}

.medians-row {
    display: grid;
    grid-template-columns: 2rem 1fr 1.2fr 1.2fr;
    gap: 0.5rem;
    padding: 0.55rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
    align-items: center;
}
.medians-row.green-border { border-inline-start-color: var(--green); background-color: rgba(var(--green-rgb), 0.08); }
.medians-row.pink-border  { border-inline-start-color: var(--pink);  background-color: rgba(var(--pink-rgb),  0.08); }
.medians-row.cyan-border  { border-inline-start-color: var(--cyan);  background-color: rgba(var(--cyan-rgb),  0.08); }

.med-row-label {
    font-size: 0.88rem;
    font-weight: 700;
}

.med-row-val {
    font-size: 0.85rem;
    font-weight: 700;
    text-align: center;
}

.medians-full-formula {
    padding-top: 0.5rem;
    display: flex;
    justify-content: center;
}

/* ============================================================
   CENTER OF GRAVITY PANEL
   ============================================================ */

.centroid-layout {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    padding-top: 0.35rem;
}

.centroid-note {
    font-size: 0.78rem;
    color: var(--text-muted);
    padding: 0 0.25rem 0.35rem;
    line-height: 1.4;
}

.centroid-header {
    display: grid;
    grid-template-columns: 2rem 1fr 1fr;
    gap: 0.5rem;
    padding: 0 0.75rem 0.25rem;
    align-items: center;
}

.centroid-col-hdr {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--text-muted);
    text-align: center;
}

.centroid-row {
    display: grid;
    grid-template-columns: 2rem 1fr 1fr;
    gap: 0.5rem;
    padding: 0.55rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
    align-items: center;
}
.centroid-row.green-border { border-inline-start-color: var(--green); background-color: rgba(var(--green-rgb), 0.08); }
.centroid-row.pink-border  { border-inline-start-color: var(--pink);  background-color: rgba(var(--pink-rgb),  0.08); }
.centroid-row.cyan-border  { border-inline-start-color: var(--cyan);  background-color: rgba(var(--cyan-rgb),  0.08); }

.centroid-row-label {
    font-size: 0.88rem;
    font-weight: 700;
}

.centroid-row-val {
    font-size: 0.85rem;
    font-weight: 700;
    text-align: center;
}

/* ============================================================
   MIDSEGMENTS PANEL
   ============================================================ */

.midseg-layout {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    padding-top: 0.35rem;
}

.midseg-header {
    display: grid;
    grid-template-columns: 2rem 1fr 1.3fr;
    gap: 0.5rem;
    padding: 0 0.75rem 0.25rem;
    align-items: center;
}

.midseg-col-hdr {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--text-muted);
    text-align: center;
}

.midseg-row {
    display: grid;
    grid-template-columns: 2rem 1fr 1.3fr;
    gap: 0.5rem;
    padding: 0.55rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
    align-items: center;
}
.midseg-row.green-border { border-inline-start-color: var(--green); background-color: rgba(var(--green-rgb), 0.08); }
.midseg-row.pink-border  { border-inline-start-color: var(--pink);  background-color: rgba(var(--pink-rgb),  0.08); }
.midseg-row.cyan-border  { border-inline-start-color: var(--cyan);  background-color: rgba(var(--cyan-rgb),  0.08); }

.midseg-row-label {
    font-size: 0.88rem;
    font-weight: 700;
}

.midseg-parallel {
    font-size: 0.82rem;
    font-weight: 600;
    text-align: center;
}

.midseg-row-val {
    font-size: 0.88rem;
    font-weight: 700;
    text-align: center;
}

.midseg-note {
    font-size: 0.78rem;
    color: var(--text-muted);
    padding: 0.25rem 0.25rem 0;
    line-height: 1.4;
}

/* ============================================================
   ANGLE BISECTORS PANEL
   ============================================================ */

.anglebis-layout {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    padding-top: 0.35rem;
}

.anglebis-header {
    display: grid;
    grid-template-columns: 2rem 1fr 1fr;
    gap: 0.5rem;
    padding: 0 0.75rem 0.25rem;
    align-items: center;
}

.anglebis-col-hdr {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--text-muted);
    text-align: center;
}

.anglebis-row {
    display: grid;
    grid-template-columns: 2rem 1fr 1fr;
    gap: 0.5rem;
    padding: 0.55rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
    align-items: center;
}
.anglebis-row.green-border { border-inline-start-color: var(--green); background-color: rgba(var(--green-rgb), 0.08); }
.anglebis-row.pink-border  { border-inline-start-color: var(--pink);  background-color: rgba(var(--pink-rgb),  0.08); }
.anglebis-row.cyan-border  { border-inline-start-color: var(--cyan);  background-color: rgba(var(--cyan-rgb),  0.08); }

.anglebis-row-label {
    font-size: 0.88rem;
    font-weight: 700;
}

.anglebis-row-desc {
    font-size: 0.78rem;
    color: var(--text-muted);
    text-align: center;
}

.anglebis-row-val {
    font-size: 0.88rem;
    font-weight: 700;
    text-align: center;
}

.anglebis-note {
    font-size: 0.78rem;
    color: var(--text-muted);
    padding: 0.25rem 0.25rem 0;
    line-height: 1.4;
}

/* ============================================================
   PERPENDICULAR BISECTORS PANEL
   ============================================================ */

.perpbis-layout {
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    padding-top: 0.35rem;
}

.perpbis-header {
    display: grid;
    grid-template-columns: 2rem 1fr 1.5fr;
    gap: 0.5rem;
    padding: 0 0.75rem 0.25rem;
    align-items: center;
}

.perpbis-col-hdr {
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--text-muted);
    text-align: center;
}

.perpbis-row {
    display: grid;
    grid-template-columns: 2rem 1fr 1.5fr;
    gap: 0.5rem;
    padding: 0.55rem 0.75rem;
    border-radius: 10px;
    border-inline-start: 4px solid transparent;
    align-items: center;
}
.perpbis-row.green-border { border-inline-start-color: var(--green); background-color: rgba(var(--green-rgb), 0.08); }
.perpbis-row.pink-border  { border-inline-start-color: var(--pink);  background-color: rgba(var(--pink-rgb),  0.08); }
.perpbis-row.cyan-border  { border-inline-start-color: var(--cyan);  background-color: rgba(var(--cyan-rgb),  0.08); }

.perpbis-row-label {
    font-size: 0.88rem;
    font-weight: 700;
}

.perpbis-row-side {
    font-size: 0.82rem;
    font-weight: 600;
    text-align: center;
}

.perpbis-row-val {
    font-size: 0.88rem;
    font-weight: 700;
    text-align: center;
}

.perpbis-note {
    font-size: 0.78rem;
    color: var(--text-muted);
    padding: 0.25rem 0.25rem 0;
    line-height: 1.4;
}

/* Dark-mode midpoint dot override */
body.dark-mode .midpoint-dot {
    fill: var(--text-secondary);
}

/* ============================================================
   SHARE MODAL
   ============================================================ */

.share-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 200;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition-normal);
}

.share-overlay.open {
    opacity: 1;
    pointer-events: all;
}

.share-panel {
    background: var(--bg-card-solid);
    border: 1.5px solid var(--border-color);
    border-radius: 20px;
    padding: 1.5rem;
    width: min(640px, 92vw);
    max-height: 85vh;
    overflow-y: auto;
    box-shadow: 0 24px 64px rgba(0, 0, 0, 0.45);
    transform: scale(0.96) translateY(8px);
    transition: transform var(--transition-normal);
}

.share-overlay.open .share-panel {
    transform: scale(1) translateY(0);
}

body.dark-mode .share-panel {
    box-shadow: 0 8px 40px rgba(0, 0, 0, 0.14);
}

.share-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.share-header h2 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.share-description {
    font-size: 0.83rem;
    color: var(--text-muted);
    line-height: 1.5;
    margin-bottom: 1.25rem;
}

.share-field {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    margin-bottom: 1.25rem;
}

.share-field:last-child {
    margin-bottom: 0;
}

.share-field-label {
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 0.07em;
    color: var(--text-muted);
    font-weight: 600;
}

.share-copy-row {
    display: flex;
    gap: 0.5rem;
    align-items: stretch;
}

.share-copy-row--code {
    align-items: flex-start;
}

.share-code-wrapper {
    flex: 1;
    min-width: 0;
    position: relative;
}

.share-input {
    flex: 1;
    min-width: 0;
    background: var(--formula-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 0.6rem 0.75rem;
    font-family: 'SF Mono', 'Monaco', 'Consolas', 'Courier New', monospace;
    font-size: 0.75rem;
    color: var(--text-secondary);
    outline: none;
    resize: none;
    transition: border-color var(--transition-fast);
    line-height: 1.5;
    direction: ltr;
    text-align: left;
}

.share-input:focus {
    border-color: var(--border-hover);
}

.share-textarea {
    height: 140px;
    white-space: pre;
    overflow-wrap: normal;
    word-break: keep-all;
}

.share-textarea-hidden {
    position: absolute;
    opacity: 0;
    pointer-events: none;
    z-index: -1;
}

.share-code-display {
    margin: 0;
    overflow-x: auto;
    overflow-y: auto;
}

/* Syntax highlighting for embed code - Light theme */
.share-code-display {
    background: #f6f8fa;
    color: #24292f;
    border-color: #d0d7de;
}

.share-code-display .tag {
    color: #116329;
    font-weight: 600;
}

.share-code-display .attr-name {
    color: #0550ae;
}

.share-code-display .attr-value {
    color: #0a3069;
}

.share-code-display .punctuation {
    color: #24292f;
}

/* Dark theme */
body.dark-mode .share-code-display {
    background: #161b22;
    color: #c9d1d9;
    border-color: #30363d;
}

body.dark-mode .share-code-display .tag {
    color: #7ee787;
    font-weight: 600;
}

body.dark-mode .share-code-display .attr-name {
    color: #79c0ff;
}

body.dark-mode .share-code-display .attr-value {
    color: #a5d6ff;
}

body.dark-mode .share-code-display .punctuation {
    color: #c9d1d9;
}

.btn-share-copy {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.3rem;
    width: 68px;
    padding: 0.5rem 0.6rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--btn-bg);
    color: var(--text-muted);
    cursor: pointer;
    font-family: var(--font-sans);
    font-size: 0.7rem;
    font-weight: 600;
    transition: border-color var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
    flex-shrink: 0;
}

.btn-share-copy:hover {
    border-color: var(--border-hover);
    background: var(--btn-hover-bg);
    color: var(--text-primary);
}

.btn-share-copy.copied {
    border-color: var(--green);
    background: rgba(var(--green-rgb), 0.1);
    color: var(--green);
}

.btn-share-copy .btn-share-label {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: clip;
}

.btn-share-copy .icon-check { display: none; }
.btn-share-copy.copied .icon-copy { display: none; }
.btn-share-copy.copied .icon-check { display: block; }
.btn-share-copy .copy-success { display: none; }
.btn-share-copy.copied .copy-idle { display: none; }
.btn-share-copy.copied .copy-success { display: inline; }

.center-hit-area {
    fill: transparent;
    pointer-events: none;
}

.center-marker {
    cursor: default;
}

.share-divider {
    height: 1px;
    background: var(--border-color);
    margin: 0 0 1.25rem;
}

.share-embed-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.4;
}