/* ==========================================================================
   FORGE HOME SCHOOL — Design System (Vitsoe / Dieter Rams)
   Direct 1:1 match with https://forgeprocedural.pages.dev/
   Enhanced with luxurious high-fidelity dynamic color accents.
   ========================================================================== */

/* --- Reset & Base --- */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Vitsoe / Dieter Rams Dark Luxury Theme (Default) */
    --bg-primary: #0e0e10;
    --bg-hero: #141418;
    --bg-card: #1a1a20;
    --bg-card-hover: #22222a;
    --text-primary: #f4f4f6;
    --text-secondary: #9a9aa2;
    --text-tertiary: #60606a;
    --rule: #222228;
    --rule-light: #1c1c22;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-glow: rgba(59, 130, 246, 0.15);
    --correct: #10b981;
    --incorrect: #ef4444;
    --input-border: #33333e;
    --input-focus: #f4f4f6;

    /* Typography scale */
    --font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Inter', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    --font-mono: 'SF Mono', 'Menlo', 'Monaco', 'Cascadia Code', monospace;
    --font-size-numeral: clamp(5rem, 8vw, 8rem);
    --font-size-h1: clamp(1.75rem, 3vw, 2.4rem);
    --font-size-h2: clamp(1.3rem, 2.2vw, 1.85rem);
    --font-size-h3: clamp(1.05rem, 1.4vw, 1.25rem);
    --font-size-body: clamp(0.95rem, 1.1vw, 1.05rem);
    --font-size-small: 0.85rem;
    --font-size-caption: 0.75rem;
    --line-height: 1.6;
    --letter-spacing-tight: -0.025em;
    --letter-spacing-wide: 0.06em;

    /* Layout */
    --max-width: 1120px;
    --margin-outer: clamp(1.5rem, 5vw, 5rem);
    --section-gap: clamp(2.5rem, 5vw, 4.5rem);
    --rule-weight: 1px;
}

[data-theme="light"] {
    --bg-primary: #f4f3f0;
    --bg-hero: #eceae6;
    --bg-card: #e4e2dc;
    --bg-card-hover: #dc Dad4;
    --text-primary: #121214;
    --text-secondary: #585860;
    --text-tertiary: #8c8c94;
    --rule: #d4d2cc;
    --rule-light: #dfddd6;
    --accent: #0079bf;
    --accent-hover: #006aa3;
    --accent-glow: rgba(0, 121, 191, 0.12);
    --correct: #2d7d46;
    --incorrect: #a63d2f;
    --input-border: #bbb9b2;
    --input-focus: #121214;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-body);
    line-height: var(--line-height);
    color: var(--text-primary);
    background-color: var(--bg-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* --- Global Top Navigation --- */
.nav-global {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.1rem var(--margin-outer);
    border-bottom: var(--rule-weight) solid var(--rule);
    background: var(--bg-primary);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-wordmark {
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: var(--letter-spacing-tight);
    color: var(--text-primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.65rem;
}

.nav-wordmark svg {
    width: 22px;
    height: 22px;
    color: var(--accent);
}

.nav-wordmark span {
    font-size: var(--font-size-small);
    font-weight: 400;
    color: var(--text-tertiary);
    margin-left: 0.25rem;
}

.nav-controls-right {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.nav-icon-btn {
    appearance: none;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6px;
    border-radius: 4px;
    transition: color 0.15s ease, background 0.15s ease;
}

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

.nav-icon-btn svg {
    width: 18px;
    height: 18px;
}

.nav-stats {
    display: flex;
    align-items: center;
    gap: 0.45rem;
    font-size: var(--font-size-small);
    color: var(--text-tertiary);
}

.nav-stats svg {
    width: 16px;
    height: 16px;
    opacity: 0.6;
}

/* --- Subject Navigation Bar --- */
.nav-subjects {
    display: flex;
    align-items: center;
    gap: 0;
    padding: 0 var(--margin-outer);
    border-bottom: var(--rule-weight) solid var(--rule);
    background: var(--bg-primary);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.nav-subjects::-webkit-scrollbar {
    display: none;
}

.nav-subject-btn {
    appearance: none;
    background: none;
    border: none;
    border-bottom: 2px solid transparent;
    padding: 0.85rem 1.15rem;
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    font-weight: 400;
    color: var(--text-secondary);
    cursor: pointer;
    white-space: nowrap;
    transition: color 0.15s ease, border-color 0.15s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-subject-btn svg {
    width: 16px;
    height: 16px;
    opacity: 0.65;
    transition: opacity 0.15s ease;
}

.nav-subject-btn:hover {
    color: var(--text-primary);
}

.nav-subject-btn:hover svg {
    opacity: 1;
}

.nav-subject-btn.active {
    font-weight: 600;
    color: var(--text-primary);
    border-bottom-color: var(--subject-accent, var(--accent));
}

.nav-subject-btn.active svg {
    opacity: 1;
    color: var(--subject-accent, var(--accent));
}

/* --- Hero Section --- */
.hero {
    background: var(--bg-hero);
    padding: clamp(2.5rem, 5vw, 4.5rem) var(--margin-outer);
    border-bottom: var(--rule-weight) solid var(--rule);
}

.hero h1 {
    font-size: var(--font-size-h1);
    letter-spacing: var(--letter-spacing-tight);
    margin-bottom: 0.35em;
    font-weight: 700;
}

.hero p {
    font-size: clamp(1rem, 1.3vw, 1.2rem);
    font-weight: 300;
    color: var(--text-secondary);
    line-height: 1.45;
    max-width: 44em;
}

/* --- Age Selector Toolbar (Vitsoe Minimal Tabs) --- */
.age-filter-bar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 1.75rem;
    flex-wrap: wrap;
}

.age-label {
    font-size: var(--font-size-caption);
    text-transform: uppercase;
    letter-spacing: var(--letter-spacing-wide);
    color: var(--text-tertiary);
    font-weight: 600;
    margin-right: 0.5rem;
}

.age-tab {
    appearance: none;
    background: var(--bg-card);
    border: var(--rule-weight) solid var(--rule);
    color: var(--text-secondary);
    padding: 0.35rem 0.85rem;
    border-radius: 2px;
    font-family: var(--font-family);
    font-size: var(--font-size-caption);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.15s ease;
}

.age-tab:hover {
    color: var(--text-primary);
    border-color: var(--text-tertiary);
}

.age-tab.active {
    background: var(--text-primary);
    color: var(--bg-primary);
    border-color: var(--text-primary);
    font-weight: 600;
}

/* --- Main Content Area --- */
.main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--margin-outer);
    width: 100%;
    flex: 1;
}

/* --- Overview Grid View --- */
.overview-section {
    padding: var(--section-gap) 0;
}

.overview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.overview-card {
    background: var(--bg-hero);
    border: var(--rule-weight) solid var(--rule);
    padding: 1.75rem;
    cursor: pointer;
    transition: border-color 0.2s ease, transform 0.15s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 200px;
}

.overview-card:hover {
    border-color: var(--subject-accent, var(--accent));
    transform: translateY(-2px);
}

.overview-card-header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 0.75rem;
}

.overview-card-header svg {
    width: 22px;
    height: 22px;
    color: var(--subject-accent, var(--accent));
}

.overview-card-title {
    font-size: 1.15rem;
    font-weight: 700;
}

.overview-card-desc {
    font-size: var(--font-size-small);
    color: var(--text-secondary);
    line-height: 1.5;
    margin-bottom: 1.5rem;
}

.overview-card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: var(--font-size-caption);
    color: var(--text-tertiary);
    border-top: var(--rule-weight) solid var(--rule);
    padding-top: 0.85rem;
    text-transform: uppercase;
    letter-spacing: var(--letter-spacing-wide);
}

/* --- Lesson View Layout (Dieter Rams Split Layout) --- */
.lesson-section {
    padding: var(--section-gap) 0;
}

.lesson-layout {
    display: grid;
    grid-template-columns: minmax(70px, 0.2fr) 1fr;
    gap: clamp(1.5rem, 4vw, 3.5rem);
    align-items: start;
}

.lesson-numeral {
    font-size: var(--font-size-numeral);
    font-weight: 700;
    line-height: 0.85;
    color: var(--subject-accent, var(--text-primary));
    letter-spacing: -0.04em;
    user-select: none;
    opacity: 0.9;
}

.lesson-content {
    max-width: 680px;
}

.lesson-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 1.25rem;
    font-size: var(--font-size-caption);
    text-transform: uppercase;
    letter-spacing: var(--letter-spacing-wide);
    color: var(--text-tertiary);
    font-weight: 600;
}

.lesson-meta-left {
    display: flex;
    align-items: center;
    gap: 0.85rem;
}

.subject-label {
    color: var(--subject-accent, var(--text-primary));
    font-weight: 700;
}

.difficulty-label {
    color: var(--text-secondary);
}

.read-aloud-btn {
    appearance: none;
    background: var(--bg-card);
    border: var(--rule-weight) solid var(--rule);
    color: var(--text-secondary);
    padding: 0.35rem 0.75rem;
    border-radius: 2px;
    font-family: var(--font-family);
    font-size: var(--font-size-caption);
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    transition: all 0.15s ease;
}

.read-aloud-btn:hover {
    color: var(--text-primary);
    border-color: var(--text-tertiary);
}

.read-aloud-btn svg {
    width: 14px;
    height: 14px;
}

.lesson-title {
    font-size: var(--font-size-h2);
    font-weight: 700;
    letter-spacing: var(--letter-spacing-tight);
    margin-bottom: 0.85rem;
}

.lesson-body {
    font-size: var(--font-size-body);
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 1.75rem;
}

/* --- p5.js Canvas Container --- */
.lesson-canvas-container {
    background: var(--bg-hero);
    border: var(--rule-weight) solid var(--rule);
    border-radius: 2px;
    margin-bottom: 2rem;
    overflow: hidden;
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 200px;
}

.lesson-canvas-container canvas {
    display: block;
    max-width: 100%;
}

/* --- Multiple Choice Option Cards --- */
.lesson-options {
    list-style: none;
    margin: 1.75rem 0;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
}

.lesson-option {
    display: flex;
    align-items: flex-start;
    gap: 0.85rem;
    padding: 0.95rem 1.15rem;
    border: var(--rule-weight) solid var(--rule);
    background: var(--bg-hero);
    border-radius: 2px;
    cursor: pointer;
    transition: border-color 0.15s ease, background 0.15s ease;
    font-size: var(--font-size-body);
}

.lesson-option:hover {
    border-color: var(--text-secondary);
    background: var(--bg-card);
}

.lesson-option.selected {
    border-color: var(--subject-accent, var(--text-primary));
    background: var(--accent-glow, var(--bg-card));
}

.option-letter {
    font-weight: 700;
    min-width: 1.5em;
    color: var(--text-tertiary);
    font-family: var(--font-mono);
}

.lesson-option.selected .option-letter {
    color: var(--subject-accent, var(--text-primary));
}

/* --- Text / Numeric Underline Input --- */
.answer-input-wrap {
    margin: 1.75rem 0;
}

.answer-input {
    width: 100%;
    max-width: 360px;
    padding: 0.75rem 0;
    border: none;
    border-bottom: 2px solid var(--input-border);
    background: transparent;
    font-family: var(--font-family);
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    outline: none;
    transition: border-color 0.2s ease;
}

.answer-input:focus {
    border-bottom-color: var(--subject-accent, var(--input-focus));
}

/* --- Sentence Builder Magnetic Blocks --- */
.sentence-builder-wrap {
    margin: 1.75rem 0;
}

.sentence-target-shelf {
    min-height: 52px;
    padding: 0.75rem;
    border: 1px dashed var(--rule);
    background: var(--bg-hero);
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.sentence-pool-shelf {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.sentence-chip {
    appearance: none;
    background: var(--bg-card);
    border: var(--rule-weight) solid var(--rule);
    color: var(--text-primary);
    padding: 0.6rem 1.1rem;
    border-radius: 2px;
    font-family: var(--font-family);
    font-size: var(--font-size-body);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
}

.sentence-chip:hover {
    border-color: var(--subject-accent, var(--text-secondary));
    background: var(--bg-card-hover);
}

/* --- Buttons (Vitsoe Clean Rectangles) --- */
.btn-group {
    display: flex;
    gap: 0.75rem;
    margin-top: 2rem;
    align-items: center;
}

.btn-primary {
    appearance: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.6rem;
    background: var(--subject-accent, var(--accent));
    color: #ffffff;
    border: none;
    border-radius: 2px;
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.15s ease, transform 0.1s ease;
}

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}

.btn-primary svg {
    width: 14px;
    height: 14px;
}

.btn-secondary {
    appearance: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.6rem;
    background: transparent;
    color: var(--text-primary);
    border: var(--rule-weight) solid var(--rule);
    border-radius: 2px;
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
}

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

.btn-secondary svg {
    width: 14px;
    height: 14px;
}

/* --- Feedback Panel --- */
.feedback {
    margin-top: 1.5rem;
    padding: 1.25rem 0;
    border-top: var(--rule-weight) solid var(--rule);
}

.feedback-status {
    font-weight: 700;
    font-size: var(--font-size-h3);
    margin-bottom: 0.4rem;
}

.feedback.correct .feedback-status {
    color: var(--correct);
}

.feedback.incorrect .feedback-status {
    color: var(--incorrect);
}

.feedback-explanation {
    color: var(--text-secondary);
    font-size: var(--font-size-body);
    line-height: 1.55;
}

/* --- Per-Subject Stats Panel --- */
.stats-panel {
    border-top: var(--rule-weight) solid var(--rule);
    margin-top: var(--section-gap);
    padding: 2.5rem 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-numeral {
    font-size: clamp(1.8rem, 3.5vw, 2.75rem);
    font-weight: 700;
    line-height: 1;
    letter-spacing: var(--letter-spacing-tight);
    margin-bottom: 0.35rem;
    color: var(--text-primary);
}

.stat-label {
    font-size: var(--font-size-caption);
    text-transform: uppercase;
    letter-spacing: var(--letter-spacing-wide);
    color: var(--text-tertiary);
    font-weight: 600;
}

/* --- Home Work TV Theater View --- */
.nav-tab-btn {
    appearance: none;
    background: var(--bg-card);
    border: var(--rule-weight) solid var(--rule);
    color: var(--text-primary);
    padding: 0.4rem 0.85rem;
    border-radius: 2px;
    font-family: var(--font-family);
    font-size: var(--font-size-small);
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: all 0.15s ease;
}

.nav-tab-btn:hover {
    border-color: var(--text-secondary);
    background: var(--bg-card-hover);
}

.nav-tab-btn.active {
    border-color: var(--accent);
    background: var(--accent-glow);
    color: var(--text-primary);
}

.nav-tab-btn svg {
    width: 16px;
    height: 16px;
    color: var(--accent);
}

.homework-tv-section {
    padding: var(--section-gap) 0;
}

.tv-theater-header {
    margin-bottom: 1.75rem;
    border-bottom: var(--rule-weight) solid var(--rule);
    padding-bottom: 1.25rem;
}

.tv-badge {
    display: inline-block;
    font-size: var(--font-size-caption);
    text-transform: uppercase;
    letter-spacing: var(--letter-spacing-wide);
    color: var(--accent);
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.tv-main-title {
    font-size: var(--font-size-h2);
    font-weight: 700;
    letter-spacing: var(--letter-spacing-tight);
    margin-bottom: 0.35rem;
}

.tv-main-subtitle {
    color: var(--text-secondary);
    font-size: var(--font-size-body);
}

.tv-player-container {
    background: #000000;
    border: var(--rule-weight) solid var(--rule);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 2.5rem;
    aspect-ratio: 16 / 9;
    max-height: 520px;
    width: 100%;
    box-shadow: 0 16px 36px -12px rgba(0, 0, 0, 0.5);
}

.tv-video-element {
    width: 100%;
    height: 100%;
    object-fit: contain;
    background: #000;
}

.tv-playlist-header {
    margin-bottom: 1.25rem;
}

.tv-playlist-header h3 {
    font-size: var(--font-size-h3);
    font-weight: 700;
    letter-spacing: var(--letter-spacing-tight);
}

.tv-playlist-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.25rem;
}

.tv-card {
    background: var(--bg-hero);
    border: var(--rule-weight) solid var(--rule);
    border-radius: 2px;
    padding: 1.25rem;
    cursor: pointer;
    transition: all 0.15s ease;
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.tv-card:hover {
    border-color: var(--text-secondary);
    background: var(--bg-card);
    transform: translateY(-2px);
}

.tv-card.active {
    border-color: var(--accent);
    background: var(--accent-glow, var(--bg-card));
}

.tv-card-play-icon {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--bg-card);
    border: var(--rule-weight) solid var(--rule);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: var(--text-primary);
}

.tv-card.active .tv-card-play-icon {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

.tv-card-play-icon svg {
    width: 14px;
    height: 14px;
    margin-left: 2px;
}

.tv-card-content {
    flex: 1;
}

.tv-card-tag {
    display: inline-block;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: var(--letter-spacing-wide);
    color: var(--accent);
    font-weight: 700;
    margin-bottom: 0.35rem;
}

.tv-card h4 {
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: 0.35rem;
    line-height: 1.35;
}

.tv-card p {
    font-size: var(--font-size-caption);
    color: var(--text-secondary);
    line-height: 1.45;
}

/* --- Footer --- */
.footer {
    border-top: var(--rule-weight) solid var(--rule);
    padding: 2rem var(--margin-outer);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: var(--font-size-caption);
    color: var(--text-tertiary);
    background: var(--bg-primary);
}

/* --- Mobile & Responsive Touch Optimization --- */
.hidden {
    display: none !important;
}

@media (max-width: 768px) {
    :root {
        --margin-outer: 1.15rem;
        --section-gap: 2rem;
        --font-size-numeral: 4rem;
    }

    .nav-global {
        padding: 0.9rem var(--margin-outer);
        padding-top: max(0.9rem, env(safe-area-inset-top));
    }

    .nav-controls-right {
        gap: 0.65rem;
    }

    .nav-tab-btn span:last-child {
        display: none;
    }

    .nav-tab-btn {
        padding: 0.45rem 0.6rem;
        min-height: 44px;
        min-width: 44px;
        justify-content: center;
    }

    .nav-icon-btn {
        min-height: 44px;
        min-width: 44px;
    }

    .nav-stats {
        display: none;
    }

    .nav-subjects {
        padding: 0 var(--margin-outer);
    }

    .nav-subject-btn {
        padding: 0.85rem 1rem;
        font-size: 0.82rem;
        min-height: 48px;
    }

    .hero {
        padding: 2rem var(--margin-outer);
    }

    .hero p {
        font-size: 0.98rem;
    }

    .age-tab {
        padding: 0.5rem 0.85rem;
        min-height: 40px;
    }

    .lesson-layout {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }

    .lesson-numeral {
        font-size: 3.5rem;
        line-height: 1;
    }

    .lesson-content {
        max-width: 100%;
    }

    .lesson-canvas-container {
        min-height: 180px;
        margin-bottom: 1.5rem;
    }

    .lesson-option {
        padding: 1rem 1.1rem;
        min-height: 52px;
    }

    .answer-input {
        max-width: 100%;
        font-size: 1.15rem;
        min-height: 48px;
    }

    .btn-group {
        flex-direction: column;
        align-items: stretch;
        gap: 0.75rem;
    }

    .btn-primary, .btn-secondary {
        width: 100%;
        justify-content: center;
        min-height: 48px;
        font-size: 0.95rem;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.25rem;
    }

    .stat-numeral {
        font-size: 1.85rem;
    }

    .tv-playlist-grid {
        grid-template-columns: 1fr;
    }

    .footer {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
        padding-bottom: max(2rem, env(safe-area-inset-bottom));
    }
}