/* Modern Glassmorphism Theme for Second Law Heat Engine Simulator */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;600;700&display=swap');

:root {
    --bg-dark: #070a12;
    --bg-card: rgba(15, 23, 42, 0.75);
    --bg-card-border: rgba(255, 255, 255, 0.1);
    --bg-card-hover: rgba(30, 41, 59, 0.85);

    --primary-blue: #38bdf8;
    --primary-cyan: #22d3ee;
    --accent-red: #ef4444;
    --accent-orange: #f97316;
    --accent-amber: #f59e0b;
    --accent-green: #22c55e;
    --accent-purple: #a855f7;

    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-dim: #64748b;

    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    --glass-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
    --radius-lg: 16px;
    --radius-md: 10px;
    --radius-sm: 6px;
}

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

body {
    background-color: var(--bg-dark);
    background-image: 
        radial-gradient(at 15% 15%, rgba(239, 68, 68, 0.12) 0px, transparent 50%),
        radial-gradient(at 85% 25%, rgba(56, 189, 248, 0.12) 0px, transparent 50%),
        radial-gradient(at 50% 85%, rgba(168, 85, 247, 0.1) 0px, transparent 50%);
    background-attachment: fixed;
    color: var(--text-main);
    font-family: var(--font-sans);
    min-height: 100vh;
    padding: 20px;
    line-height: 1.5;
}

/* App Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1400px;
    margin: 0 auto 20px auto;
    padding: 16px 24px;
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    border: 1px solid var(--bg-card-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--glass-shadow);
}

.brand {
    display: flex;
    align-items: center;
    gap: 14px;
}

.brand-icon {
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--accent-orange), var(--primary-blue));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    box-shadow: 0 0 15px rgba(249, 115, 22, 0.4);
}

.brand-title h1 {
    font-size: 20px;
    font-weight: 800;
    letter-spacing: 0.5px;
    background: linear-gradient(90deg, #ffffff, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.brand-title p {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

.header-badges {
    display: flex;
    gap: 10px;
}

.law-badge {
    background: rgba(56, 189, 248, 0.15);
    border: 1px solid rgba(56, 189, 248, 0.3);
    color: var(--primary-blue);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.5px;
}

/* Layout Grid */
.layout-container {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 360px 1fr;
    gap: 20px;
}

@media (max-width: 1024px) {
    .layout-container {
        grid-template-columns: 1fr;
    }
}

/* Cards & Containers */
.glass-card {
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    border: 1px solid var(--bg-card-border);
    border-radius: var(--radius-lg);
    padding: 20px;
    box-shadow: var(--glass-shadow);
    transition: transform 0.2s ease, border-color 0.2s ease;
}

.glass-card:hover {
    border-color: rgba(255, 255, 255, 0.2);
}

.card-title {
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    color: var(--text-main);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    padding-bottom: 10px;
}

.card-title i {
    color: var(--primary-cyan);
}

/* Control Panel Inputs */
.control-group {
    margin-bottom: 18px;
}

.control-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 6px;
}

.val-badge {
    font-family: var(--font-mono);
    font-size: 13px;
    font-weight: 700;
    color: var(--primary-blue);
    background: rgba(56, 189, 248, 0.1);
    padding: 2px 8px;
    border-radius: 4px;
    border: 1px solid rgba(56, 189, 248, 0.2);
}

/* Styled Range Sliders */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 6px;
    background: #1e293b;
    border-radius: 3px;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--primary-blue);
    cursor: pointer;
    box-shadow: 0 0 10px var(--primary-blue);
    transition: transform 0.1s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

/* Mode Switch Segmented Controls */
.segmented-control {
    display: grid;
    grid-template-columns: 1fr 1fr;
    background: #0f172a;
    padding: 4px;
    border-radius: var(--radius-md);
    border: 1px solid var(--bg-card-border);
    margin-bottom: 16px;
}

.segmented-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 8px 12px;
    font-size: 12px;
    font-weight: 600;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s ease;
}

.segmented-btn.active {
    background: linear-gradient(135deg, #1e293b, #334155);
    color: var(--primary-cyan);
    box-shadow: 0 2px 8px rgba(0,0,0,0.4);
    border: 1px solid rgba(56, 189, 248, 0.4);
}

/* Action Buttons */
.btn-group {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

.btn {
    flex: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 16px;
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    border: none;
    transition: all 0.2s ease;
}

.btn-primary {
    background: linear-gradient(135deg, #0284c7, #2563eb);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.6);
}

.btn-secondary {
    background: #1e293b;
    color: var(--text-main);
    border: 1px solid rgba(255,255,255,0.1);
}

.btn-secondary:hover {
    background: #334155;
}

.btn-accent {
    background: linear-gradient(135deg, var(--accent-purple), #7c3aed);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(168, 85, 247, 0.4);
}

/* Presets Container */
.presets-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    margin-top: 10px;
}

.preset-chip {
    background: #0f172a;
    border: 1px solid var(--bg-card-border);
    color: var(--text-muted);
    padding: 8px;
    border-radius: var(--radius-sm);
    font-size: 11px;
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    transition: all 0.2s ease;
}

.preset-chip:hover {
    border-color: var(--primary-cyan);
    color: var(--primary-cyan);
    background: rgba(34, 211, 238, 0.05);
}

/* Live Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-bottom: 20px;
}

@media (max-width: 768px) {
    .metrics-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.metric-card {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--bg-card-border);
    padding: 14px;
    border-radius: var(--radius-md);
    text-align: center;
}

.metric-title {
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.metric-val {
    font-family: var(--font-mono);
    font-size: 18px;
    font-weight: 800;
    color: var(--text-main);
}

.metric-sub {
    font-size: 10px;
    color: var(--text-dim);
    margin-top: 2px;
}

/* Visual Canvas Layout */
.visualization-grid {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 16px;
    margin-bottom: 20px;
}

@media (max-width: 1100px) {
    .visualization-grid {
        grid-template-columns: 1fr;
    }
}

.canvas-wrapper {
    position: relative;
    width: 100%;
    border-radius: var(--radius-md);
    overflow: hidden;
    background: #090d16;
    border: 1px solid var(--bg-card-border);
}

canvas {
    display: block;
    width: 100%;
    height: auto;
}

/* Tab Panels */
.tab-header {
    display: flex;
    gap: 10px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    margin-bottom: 16px;
}

.tab-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 10px 16px;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
}

.tab-btn.active {
    color: var(--primary-cyan);
    border-bottom-color: var(--primary-cyan);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Observation Table */
.table-wrapper {
    overflow-x: auto;
    border-radius: var(--radius-md);
    border: 1px solid var(--bg-card-border);
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 12px;
}

th {
    background: #0f172a;
    color: var(--text-muted);
    font-weight: 700;
    padding: 10px;
    text-align: center;
    border-bottom: 1px solid var(--bg-card-border);
}

td {
    padding: 10px;
    text-align: center;
    border-bottom: 1px solid rgba(255,255,255,0.05);
    font-family: var(--font-mono);
}

tr:nth-child(even) {
    background: rgba(255, 255, 255, 0.02);
}

/* Educational Panel Cards */
.theory-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 16px;
}

.theory-card {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--bg-card-border);
    padding: 16px;
    border-radius: var(--radius-md);
}

.theory-card h4 {
    color: var(--primary-blue);
    font-size: 14px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.theory-card p {
    font-size: 12px;
    color: var(--text-muted);
    line-height: 1.6;
}

.formula-box {
    background: #0f172a;
    border-left: 3px solid var(--primary-cyan);
    padding: 8px 12px;
    margin: 10px 0;
    font-family: var(--font-mono);
    font-size: 12px;
    color: #e2e8f0;
}

/* Second Law Statement Banner */
.law-statement-banner {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.15), rgba(168, 85, 247, 0.15));
    border: 1px solid rgba(239, 68, 68, 0.3);
    padding: 16px 20px;
    border-radius: var(--radius-md);
    margin-bottom: 20px;
}

.law-statement-banner h3 {
    color: #fca5a5;
    font-size: 15px;
    margin-bottom: 6px;
}

.law-statement-banner ul {
    list-style-type: none;
    font-size: 13px;
    color: var(--text-main);
}

.law-statement-banner li {
    margin-bottom: 4px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.law-statement-banner li::before {
    content: "•";
    color: var(--accent-orange);
    font-weight: bold;
}

/* Quiz Box Styling */
.quiz-box {
    background: rgba(15, 23, 42, 0.6);
}

.quiz-question-title {
    color: var(--text-main);
}

/* ==========================================================================
   LIGHT THEME OVERRIDES
   ========================================================================== */

html[data-theme="light"],
html:not(.dark):not([data-theme="dark"]) {
    --bg-dark: #f8fafc;
    --bg-card: #ffffff;
    --bg-card-border: #e2e8f0;
    --bg-card-hover: #f1f5f9;

    --text-main: #0f172a;
    --text-muted: #475569;
    --text-dim: #64748b;

    --glass-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
}

html[data-theme="light"] body,
html:not(.dark):not([data-theme="dark"]) body {
    background-color: #f8fafc;
    background-image: 
        radial-gradient(at 15% 15%, rgba(239, 68, 68, 0.04) 0px, transparent 50%),
        radial-gradient(at 85% 25%, rgba(56, 189, 248, 0.04) 0px, transparent 50%),
        radial-gradient(at 50% 85%, rgba(168, 85, 247, 0.04) 0px, transparent 50%);
    color: #0f172a;
}

html[data-theme="light"] .app-header,
html:not(.dark):not([data-theme="dark"]) .app-header {
    background: #ffffff;
    border-color: #e2e8f0;
    box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
}

html[data-theme="light"] .brand-title h1,
html:not(.dark):not([data-theme="dark"]) .brand-title h1 {
    background: linear-gradient(90deg, #0f172a, #0284c7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

html[data-theme="light"] .brand-title p,
html:not(.dark):not([data-theme="dark"]) .brand-title p {
    color: #64748b;
}

html[data-theme="light"] .law-badge,
html:not(.dark):not([data-theme="dark"]) .law-badge {
    background: #f0f9ff;
    border-color: #bae6fd;
    color: #0284c7;
}

html[data-theme="light"] .glass-card,
html:not(.dark):not([data-theme="dark"]) .glass-card {
    background: #ffffff;
    border-color: #e2e8f0;
    box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
}

html[data-theme="light"] .glass-card:hover,
html:not(.dark):not([data-theme="dark"]) .glass-card:hover {
    border-color: #cbd5e1;
}

html[data-theme="light"] .card-title,
html:not(.dark):not([data-theme="dark"]) .card-title {
    color: #0f172a;
    border-bottom-color: #e2e8f0;
}

html[data-theme="light"] .control-label,
html:not(.dark):not([data-theme="dark"]) .control-label {
    color: #334155;
}

html[data-theme="light"] .val-badge,
html:not(.dark):not([data-theme="dark"]) .val-badge {
    background: #f0f9ff;
    border-color: #bae6fd;
    color: #0284c7;
}

html[data-theme="light"] input[type="range"],
html:not(.dark):not([data-theme="dark"]) input[type="range"] {
    background: #e2e8f0;
}

html[data-theme="light"] .segmented-control,
html:not(.dark):not([data-theme="dark"]) .segmented-control {
    background: #f1f5f9;
    border-color: #e2e8f0;
}

html[data-theme="light"] .segmented-btn,
html:not(.dark):not([data-theme="dark"]) .segmented-btn {
    color: #64748b;
}

html[data-theme="light"] .segmented-btn.active,
html:not(.dark):not([data-theme="dark"]) .segmented-btn.active {
    background: #ffffff;
    color: #0284c7;
    border-color: #bae6fd;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.06);
}

html[data-theme="light"] .btn-secondary,
html:not(.dark):not([data-theme="dark"]) .btn-secondary {
    background: #f1f5f9;
    color: #334155;
    border-color: #e2e8f0;
}

html[data-theme="light"] .btn-secondary:hover,
html:not(.dark):not([data-theme="dark"]) .btn-secondary:hover {
    background: #e2e8f0;
}

html[data-theme="light"] .preset-chip,
html:not(.dark):not([data-theme="dark"]) .preset-chip {
    background: #f8fafc;
    border-color: #e2e8f0;
    color: #334155;
}

html[data-theme="light"] .preset-chip:hover,
html:not(.dark):not([data-theme="dark"]) .preset-chip:hover {
    background: #f0f9ff;
    border-color: #0284c7;
    color: #0284c7;
}

html[data-theme="light"] .law-statement-banner,
html:not(.dark):not([data-theme="dark"]) .law-statement-banner {
    background: linear-gradient(135deg, rgba(254, 226, 226, 0.6), rgba(243, 232, 255, 0.6));
    border-color: #fca5a5;
}

html[data-theme="light"] .law-statement-banner h3,
html:not(.dark):not([data-theme="dark"]) .law-statement-banner h3 {
    color: #991b1b;
}

html[data-theme="light"] .law-statement-banner ul,
html:not(.dark):not([data-theme="dark"]) .law-statement-banner ul {
    color: #334155;
}

html[data-theme="light"] .metric-card,
html:not(.dark):not([data-theme="dark"]) .metric-card {
    background: #f8fafc;
    border-color: #e2e8f0;
}

html[data-theme="light"] .metric-title,
html:not(.dark):not([data-theme="dark"]) .metric-title {
    color: #64748b;
}

html[data-theme="light"] .metric-val,
html:not(.dark):not([data-theme="dark"]) .metric-val {
    color: #0f172a;
}

html[data-theme="light"] .metric-sub,
html:not(.dark):not([data-theme="dark"]) .metric-sub {
    color: #64748b;
}

html[data-theme="light"] .canvas-wrapper,
html:not(.dark):not([data-theme="dark"]) .canvas-wrapper {
    background: #f8fafc;
    border-color: #e2e8f0;
}

html[data-theme="light"] .tab-header,
html:not(.dark):not([data-theme="dark"]) .tab-header {
    border-bottom-color: #e2e8f0;
}

html[data-theme="light"] .tab-btn,
html:not(.dark):not([data-theme="dark"]) .tab-btn {
    color: #64748b;
}

html[data-theme="light"] .tab-btn.active,
html:not(.dark):not([data-theme="dark"]) .tab-btn.active {
    color: #0284c7;
    border-bottom-color: #0284c7;
}

html[data-theme="light"] .table-wrapper,
html:not(.dark):not([data-theme="dark"]) .table-wrapper {
    border-color: #e2e8f0;
}

html[data-theme="light"] th,
html:not(.dark):not([data-theme="dark"]) th {
    background: #f1f5f9;
    color: #0369a1;
    border-bottom-color: #e2e8f0;
}

html[data-theme="light"] td,
html:not(.dark):not([data-theme="dark"]) td {
    color: #334155;
    border-bottom-color: #e2e8f0;
}

html[data-theme="light"] tr:nth-child(even),
html:not(.dark):not([data-theme="dark"]) tr:nth-child(even) {
    background: #f8fafc;
}

html[data-theme="light"] .theory-card,
html:not(.dark):not([data-theme="dark"]) .theory-card {
    background: #f8fafc;
    border-color: #e2e8f0;
}

html[data-theme="light"] .theory-card h4,
html:not(.dark):not([data-theme="dark"]) .theory-card h4 {
    color: #0284c7;
}

html[data-theme="light"] .theory-card p,
html:not(.dark):not([data-theme="dark"]) .theory-card p {
    color: #334155;
}

html[data-theme="light"] .formula-box,
html:not(.dark):not([data-theme="dark"]) .formula-box {
    background: #ffffff;
    border: 1px solid #bae6fd;
    border-left: 3px solid #0284c7;
    color: #0369a1;
}

html[data-theme="light"] .quiz-box,
html:not(.dark):not([data-theme="dark"]) .quiz-box {
    background: #f8fafc;
    border-color: #e2e8f0;
}

html[data-theme="light"] .quiz-question-title,
html:not(.dark):not([data-theme="dark"]) .quiz-question-title {
    color: #0f172a;
}