@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;600&display=swap');

:root {
    --bg-outer: #d4c5a9;
    --bg-page: #faf6ee;
    --bg-card: #fdfbf7;
    --bg-svg: #fffdf8;
    --bg-insight: #fdf8ee;
    --bg-active: #faf3e6;

    --text-primary: #362b1f;
    --text-heading: #2c2416;
    --text-h2: #3d2e1c;
    --text-h3: #4a3828;
    --text-muted: #6b5b47;
    --text-subtle: #7a6b57;
    --text-insight: #5a4630;

    --border-main: #e8dfd0;
    --border-section: #e0d5c4;
    --border-card: #ddd4c4;
    --border-input: #c4b99a;

    --accent: #8b6f47;
    --accent-hover: #6d5636;
    --accent-border: #c4a882;
    --accent-green: #5a7a5c;
    --accent-green-hover: #476248;

    --case1: #a04000;
    --case2: #5c2d82;
    --case3: #2e6b30;

    --red-node: #a02020;
    --black-node: #1a1410;

    --btn-disabled-bg: #c4b99a;
    --btn-disabled-text: #8a7d6b;

    --shadow-page: 0 1px 3px rgba(0, 0, 0, 0.08), 0 8px 24px rgba(0, 0, 0, 0.06);
    --shadow-inset: inset 0 0 80px rgba(139, 115, 85, 0.03);
    --shadow-card-active: 0 2px 8px rgba(139, 111, 71, 0.12);
    --shadow-suggestion: 0 2px 6px rgba(139, 111, 71, 0.1);

    --lines-color: rgba(139, 115, 85, 0.02);
    --gradient1: rgba(139, 115, 85, 0.08);
    --gradient2: rgba(139, 115, 85, 0.05);

    --toggle-bg: #e0d5c4;
    --toggle-knob: #8b6f47;
}

[data-theme="sepia"] {
    --bg-outer: #c8b68e;
    --bg-page: #f4e8cd;
    --bg-card: #f7ecd5;
    --bg-svg: #f5e9d0;
    --bg-insight: #f0e2c2;
    --bg-active: #eedcb8;

    --text-primary: #3d2e1a;
    --text-heading: #2a1e10;
    --text-h2: #3d2e1a;
    --text-h3: #4d3c24;
    --text-muted: #6b5535;
    --text-subtle: #7a6545;
    --text-insight: #5a4420;

    --border-main: #dcc9a0;
    --border-section: #d4be94;
    --border-card: #d4be94;
    --border-input: #b89e6e;

    --accent: #7a5c2e;
    --accent-hover: #5c4420;
    --accent-border: #b89e6e;
    --accent-green: #4a6a3a;
    --accent-green-hover: #3a5a2a;

    --case1: #944000;
    --case2: #5a2d6e;
    --case3: #2e6020;

    --red-node: #942020;
    --black-node: #2a1e10;

    --btn-disabled-bg: #b89e6e;
    --btn-disabled-text: #8a7550;

    --shadow-page: 0 1px 3px rgba(0, 0, 0, 0.1), 0 8px 24px rgba(0, 0, 0, 0.08);
    --shadow-inset: inset 0 0 80px rgba(139, 115, 85, 0.05);
    --shadow-card-active: 0 2px 8px rgba(122, 92, 46, 0.15);
    --shadow-suggestion: 0 2px 6px rgba(122, 92, 46, 0.12);

    --lines-color: rgba(139, 115, 85, 0.03);
    --gradient1: rgba(139, 115, 85, 0.1);
    --gradient2: rgba(139, 115, 85, 0.06);

    --toggle-bg: #d4be94;
    --toggle-knob: #7a5c2e;
}

[data-theme="dark"] {
    --bg-outer: #1a1a1a;
    --bg-page: #252220;
    --bg-card: #2d2a27;
    --bg-svg: #2a2725;
    --bg-insight: #302b24;
    --bg-active: #3a3228;

    --text-primary: #e0d5c4;
    --text-heading: #f0e8dc;
    --text-h2: #e8dfd0;
    --text-h3: #d4c5a9;
    --text-muted: #a89880;
    --text-subtle: #9a8b74;
    --text-insight: #c4b99a;

    --border-main: #3d3530;
    --border-section: #4a4038;
    --border-card: #4a4038;
    --border-input: #5a4e42;

    --accent: #c4a882;
    --accent-hover: #d4b892;
    --accent-border: #8b6f47;
    --accent-green: #7aa87c;
    --accent-green-hover: #8dba8f;

    --case1: #e07030;
    --case2: #b080e0;
    --case3: #60b060;

    --red-node: #e05050;
    --black-node: #f0e8dc;

    --btn-disabled-bg: #3d3530;
    --btn-disabled-text: #6b5b47;

    --shadow-page: 0 1px 3px rgba(0, 0, 0, 0.3), 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-inset: inset 0 0 80px rgba(0, 0, 0, 0.1);
    --shadow-card-active: 0 2px 8px rgba(196, 168, 130, 0.15);
    --shadow-suggestion: 0 2px 6px rgba(196, 168, 130, 0.1);

    --lines-color: rgba(255, 255, 255, 0.015);
    --gradient1: rgba(255, 255, 255, 0.02);
    --gradient2: rgba(255, 255, 255, 0.01);

    --toggle-bg: #4a4038;
    --toggle-knob: #c4a882;
}

[data-theme="hacker"] {
    --bg-outer: #000000;
    --bg-page: #0a0a0a;
    --bg-card: #111111;
    --bg-svg: #0d0d0d;
    --bg-insight: #0a1a0a;
    --bg-active: #0a200a;

    --text-primary: #33ff33;
    --text-heading: #44ff44;
    --text-h2: #33ee33;
    --text-h3: #22cc22;
    --text-muted: #1a991a;
    --text-subtle: #158015;
    --text-insight: #22aa22;

    --border-main: #1a331a;
    --border-section: #1a3a1a;
    --border-card: #1a331a;
    --border-input: #2a552a;

    --accent: #33ff33;
    --accent-hover: #66ff66;
    --accent-border: #1a661a;
    --accent-green: #33ff33;
    --accent-green-hover: #66ff66;

    --case1: #ff6633;
    --case2: #cc66ff;
    --case3: #33ff99;

    --red-node: #ff3333;
    --black-node: #33ff33;

    --btn-disabled-bg: #1a331a;
    --btn-disabled-text: #0d4d0d;

    --shadow-page: 0 0 20px rgba(0, 255, 0, 0.05), 0 0 60px rgba(0, 255, 0, 0.02);
    --shadow-inset: inset 0 0 80px rgba(0, 255, 0, 0.02);
    --shadow-card-active: 0 0 12px rgba(51, 255, 51, 0.15);
    --shadow-suggestion: 0 0 8px rgba(51, 255, 51, 0.1);

    --lines-color: rgba(0, 255, 0, 0.02);
    --gradient1: rgba(0, 255, 0, 0.03);
    --gradient2: rgba(0, 255, 0, 0.01);

    --toggle-bg: #1a331a;
    --toggle-knob: #33ff33;
}

[data-theme="hacker"] .container {
    border-color: #1a3a1a;
    box-shadow: 0 0 30px rgba(0, 255, 0, 0.04), inset 0 0 60px rgba(0, 255, 0, 0.01);
}

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

a {
    color: var(--accent);
    text-decoration-color: var(--accent-border);
}

a:hover {
    color: var(--accent-hover);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    font-size: 0.95rem;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-outer);
    background-image:
        radial-gradient(ellipse at 20% 50%, var(--gradient1) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, var(--gradient2) 0%, transparent 50%);
    padding: 2.5rem;
    min-height: 100vh;
    transition: background 0.3s, color 0.3s;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    background: var(--bg-page);
    padding: 2.5rem 3rem;
    border-radius: 3px;
    box-shadow: var(--shadow-page);
    border: 1px solid var(--border-main);
    position: relative;
    transition: background 0.3s, border-color 0.3s, box-shadow 0.3s;
}


/* --- Breadcrumb --- */

.breadcrumb {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.breadcrumb a {
    color: var(--text-muted);
    text-decoration: none;
}

.breadcrumb a:hover {
    color: var(--accent);
}

/* --- Theme Toggle --- */

.theme-toggle {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.25rem;
    z-index: 10;
}

.theme-btn {
    font-size: 0.72rem;
    font-family: 'JetBrains Mono', monospace;
    padding: 0.25rem 0.5rem;
    border: 1px solid var(--border-card);
    border-radius: 2px;
    background: transparent;
    color: var(--text-muted);
    cursor: pointer;
    transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.theme-btn:hover {
    color: var(--text-primary);
    border-color: var(--accent);
}

.theme-btn.active {
    background: var(--accent);
    color: var(--bg-page);
    border-color: var(--accent);
}


/* --- Typography --- */

h1 {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 2.5rem;
    color: var(--text-heading);
    text-align: center;
    letter-spacing: -0.5px;
    border-bottom: 1px solid var(--accent-border);
    padding-bottom: 1.2rem;
    transition: color 0.3s, border-color 0.3s;
}

h2 {
    font-size: 1.4rem;
    font-weight: 600;
    margin-top: 0.5rem;
    margin-bottom: 1rem;
    color: var(--text-h2);
    letter-spacing: -0.3px;
    transition: color 0.3s;
}

h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-top: 0.8rem;
    margin-bottom: 0.4rem;
    color: var(--text-h3);
    transition: color 0.3s;
}

section {
    background: transparent;
    border-radius: 0;
    padding: 0.8rem 0;
    margin-bottom: 0;
    box-shadow: none;
    border-bottom: none;
}

section:last-child {
    border-bottom: none;
}

p {
    margin-bottom: 0.5rem;
}

.intro ol {
    margin: 1rem 0 1rem 2rem;
    list-style: none;
    counter-reset: rule-counter;
}

.intro li {
    margin-bottom: 0.5rem;
    counter-increment: rule-counter;
    position: relative;
    padding-left: 0.5rem;
}

.intro li::before {
    content: counter(rule-counter) ".";
    position: absolute;
    left: -1.8rem;
    color: var(--accent);
    font-weight: 600;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
}

.key-insight {
    margin-top: 1rem;
    padding: 0.8rem 1.2rem;
    background: var(--bg-insight);
    border-left: 3px solid var(--accent-border);
    border-radius: 0;
    font-style: italic;
    color: var(--text-insight);
    transition: background 0.3s, border-color 0.3s, color 0.3s;
}

.red-text {
    color: var(--red-node);
    font-weight: 700;
    font-style: normal;
}

.black-text {
    color: var(--black-node);
    font-weight: 700;
    font-style: normal;
}

/* --- Case Cards --- */

.case-card {
    border: 1px solid var(--border-card);
    border-radius: 2px;
    padding: 1rem 1.2rem;
    margin-bottom: 1rem;
    background: var(--bg-card);
    transition: border-color 0.3s, background 0.3s, box-shadow 0.3s;
}

.case-card:last-child {
    margin-bottom: 0;
}

.case-card.active {
    border-color: var(--accent);
    background: var(--bg-active);
    box-shadow: var(--shadow-card-active);
}

#case1-card h3 { color: var(--case1); }
#case2-card h3 { color: var(--case2); }
#case3-card h3 { color: var(--case3); }

.case-diagram {
    margin: 0.8rem 0;
    padding: 0.8rem 1rem;
    background: var(--bg-svg);
    border: 1px solid var(--border-card);
    border-radius: 2px;
    transition: background 0.3s, border-color 0.3s;
}

.diagram-pair {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.diagram-side {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.diagram-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.72rem;
    color: var(--text-muted);
    margin-top: 0.2rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.diagram-arrow {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--accent);
    padding: 0 0.3rem;
}

.case-svg {
    display: block;
}

/* --- Rotation Details --- */

.rotation-details {
    margin: 0.8rem 0;
    padding: 0.6rem 1rem;
    background: var(--bg-svg);
    border: 1px solid var(--border-card);
    border-radius: 2px;
    transition: background 0.3s, border-color 0.3s;
}

.appendix {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px dashed var(--border-section);
    font-size: 0.88rem;
    color: var(--text-muted);
}

.appendix h2 {
    font-size: 1.1rem;
    color: var(--text-subtle);
}

.appendix h3 {
    font-size: 0.95rem;
    color: var(--text-subtle);
}

.appendix p {
    color: var(--text-muted);
}

.appendix a {
    color: var(--text-subtle);
}

.rotation-details summary {
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--accent);
    padding: 0.2rem 0;
}

.rotation-details summary:hover {
    color: var(--accent-hover);
}

.rotation-details[open] summary {
    margin-bottom: 0.6rem;
}

.rotation-details p {
    font-size: 0.95rem;
}

/* --- Rotation Animation --- */

.rotation-anim-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.rotation-anim-svg {
    display: block;
    overflow: visible;
    min-height: 160px;
}

.rotation-step-text {
    font-family: 'Inter', sans-serif;
    font-size: 0.88rem;
    color: var(--text-muted);
    text-align: center;
    min-height: 1.4em;
    transition: color 0.3s;
}

.rotation-btn-row {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.rotation-play-btn {
    padding: 0.3rem 1rem;
    border: 1px solid var(--accent);
    border-radius: 2px;
    background: var(--accent);
    color: var(--bg-page);
    font-size: 0.8rem;
    font-family: 'JetBrains Mono', monospace;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s, color 0.3s;
    letter-spacing: 0.3px;
}

.rotation-play-btn:hover {
    background: var(--accent-hover);
}

.rotation-play-btn:active {
    transform: scale(0.97);
}

.rotation-play-btn:disabled {
    background: var(--btn-disabled-bg);
    border-color: var(--btn-disabled-bg);
    color: var(--btn-disabled-text);
    cursor: not-allowed;
}

.diagram-note {
    font-family: 'Inter', sans-serif;
    font-size: 0.88rem;
    font-style: italic;
    color: var(--text-muted);
    margin-top: 0.5rem;
    margin-bottom: 0.8rem;
    text-align: center;
}

.diagram-variant-label {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.74rem;
    font-weight: 600;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.3rem;
    margin-top: 0.2rem;
}


/* --- Quiz Panel --- */

#quiz-panel {
    margin-bottom: 0.8rem;
}

#quiz-panel:empty {
    display: none;
}

.quiz-question {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-h3);
    margin-bottom: 0.5rem;
}

.quiz-choices {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.quiz-choice {
    padding: 0.5rem 0.8rem;
    border: 1px solid var(--border-card);
    border-radius: 2px;
    background: var(--bg-card);
    font-family: 'Inter', sans-serif;
    font-size: 0.92rem;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s, transform 0.1s;
}

.quiz-choice:hover {
    border-color: var(--accent);
    transform: translateX(2px);
}

.quiz-choice.correct {
    border-color: var(--accent-green);
    background: rgba(90, 122, 92, 0.15);
    animation: flash-correct 0.4s;
}

.quiz-choice.wrong {
    border-color: #c0392b;
    background: rgba(192, 57, 43, 0.1);
    animation: shake 0.4s;
}

.quiz-result {
    font-size: 0.85rem;
    margin-top: 0.4rem;
    font-style: italic;
    color: var(--text-muted);
}

.quiz-result.correct {
    color: var(--accent-green);
}

.quiz-score {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.4rem;
}

.quiz-hint {
    font-size: 0.85rem;
    color: var(--case1);
    margin-top: 0.5rem;
    font-style: italic;
    padding: 0.4rem 0.6rem;
    background: var(--bg-insight);
    border-left: 2px solid var(--accent-border);
    border-radius: 2px;
}

.next-hint {
    font-size: 0.88rem;
    color: var(--text-muted);
    margin-bottom: 0.8rem;
    min-height: 1.5em;
}

.next-hint .hint-label {
    font-weight: 600;
    color: var(--text-h3);
}

#insert-next-btn span {
    font-family: 'JetBrains Mono', monospace;
    font-weight: 700;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

@keyframes flash-correct {
    0% { background: rgba(90, 122, 92, 0.3); }
    100% { background: rgba(90, 122, 92, 0.15); }
}

.cases-explanation p {
    font-size: 1rem;
}

/* --- Flowchart --- */

.flowchart-container {
    margin: 1.5rem 0;
    padding: 1rem 1.2rem;
    background: var(--bg-svg);
    border: 1px solid var(--border-card);
    border-radius: 2px;
    transition: background 0.3s, border-color 0.3s;
}

.flowchart-container h3 {
    margin-bottom: 0.8rem;
}

.flowchart-svg {
    display: block;
    max-width: 100%;
    height: auto;
}

/* --- Comparison Table --- */

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: 1rem 0;
    font-size: 0.9rem;
}

.comparison-table th,
.comparison-table td {
    padding: 0.5rem 0.8rem;
    border: 1px solid var(--border-card);
    text-align: left;
    transition: border-color 0.3s;
}

.comparison-table th {
    background: var(--bg-svg);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-h3);
    transition: background 0.3s, color 0.3s;
}

.comparison-table td:first-child {
    font-weight: 600;
    color: var(--text-h3);
    white-space: nowrap;
}

/* --- Workspace Layout --- */

.workspace {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.tree-panel {
    flex: 1;
    min-width: 0;
}

#tree-canvas {
    width: 100%;
    height: 400px;
    background: var(--bg-svg);
    border: 1px solid var(--border-card);
    border-radius: 2px;
    box-shadow: inset 0 1px 4px rgba(139, 115, 85, 0.06);
    transition: background 0.3s, border-color 0.3s;
}

/* --- Controls --- */

.controls {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.8rem;
    flex-wrap: wrap;
    align-items: stretch;
}


.insert-row {
    display: flex;
    align-items: stretch;
    gap: 0.4rem;
}

.insert-or {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    align-self: center;
}

.custom-input {
    width: 100px;
    padding: 0.5rem 0.6rem;
    border: 1px solid var(--border-input);
    border-radius: 2px;
    background: var(--bg-card);
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 1rem;
    transition: border-color 0.2s, background 0.3s, color 0.3s;
}

.custom-input:focus {
    outline: none;
    border-color: var(--accent);
}

.controls button {
    padding: 0.4rem 1rem;
    border: 1px solid var(--accent);
    border-radius: 2px;
    background: var(--accent);
    color: var(--bg-page);
    font-size: 0.85rem;
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s, color 0.3s;
    letter-spacing: 0.3px;
}

.controls button:hover {
    background: var(--accent-hover);
}

.controls button:active {
    transform: scale(0.97);
}

/* --- Suggestions Panel --- */

.suggestions-panel {
    width: 360px;
    flex-shrink: 0;
}

.suggestions-panel h3 {
    margin-bottom: 0.8rem;
    color: var(--text-insight);
}


/* --- Action / Steps Panel --- */

#last-action:empty {
    display: none;
}

#last-action {
    margin-top: 0;
    padding: 1rem;
    border-radius: 2px;
    background: var(--bg-card);
    border: 1px solid var(--border-section);
    font-size: 0.92rem;
    line-height: 1.6;
    transition: background 0.3s, border-color 0.3s;
}

#last-action .step {
    margin-bottom: 0.4rem;
    padding-left: 0.8rem;
    border-left: 2px solid var(--accent-border);
}

.instructions {
    color: var(--text-muted);
    margin-bottom: 1rem;
    font-style: italic;
}

/* --- Step Controls --- */

.step-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.6rem;
    flex-wrap: wrap;
}

.step-controls button {
    padding: 0.4rem 0.8rem;
    border: 1px solid var(--accent-green);
    border-radius: 2px;
    background: var(--accent-green);
    color: var(--bg-page);
    font-size: 0.82rem;
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s, color 0.3s;
}

.step-controls button:hover {
    background: var(--accent-green-hover);
}

.step-controls button:active {
    transform: scale(0.97);
}

.step-controls button:disabled {
    background: var(--btn-disabled-bg);
    border-color: var(--btn-disabled-bg);
    color: var(--btn-disabled-text);
    cursor: not-allowed;
}

.step-indicator {
    font-size: 0.85rem;
    color: var(--text-muted);
    min-width: 50px;
    text-align: center;
    font-family: 'JetBrains Mono', monospace;
}

.frame-counter {
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--accent);
    margin-bottom: 0.4rem;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    font-family: 'JetBrains Mono', monospace;
}

#last-action .why {
    margin-top: 0.4rem;
    color: var(--text-muted);
    font-style: italic;
    border-left-color: var(--accent-green);
}

/* --- Responsive --- */

@media (max-width: 800px) {
    .workspace {
        flex-direction: column;
    }
    .suggestions-panel {
        width: 100%;
    }
    body {
        padding: 1rem;
    }
    .container {
        padding: 2rem 1.5rem;
    }
    .theme-toggle {
        top: 1rem;
        right: 1rem;
    }
}