/* Automata Theory Learning - Common Styles */
/* Dark Mode Theme */

:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --bg-card: #1c2128;
    --border-color: #30363d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --accent-blue: #58a6ff;
    --accent-green: #3fb950;
    --accent-purple: #a371f7;
    --accent-orange: #d29922;
    --accent-red: #f85149;
    --accent-cyan: #39c5cf;
    --code-bg: #0d1117;
    --highlight-bg: #388bfd26;
    --shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.3);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, 'Roboto', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    min-height: 100vh;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
}

/* Header */
header {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-blue);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.module-badge {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    border: 1px solid var(--border-color);
}

/* Main Content */
main {
    padding: 40px 0;
}

/* Typography */
h1, h2, h3, h4, h5 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    line-height: 1.3;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1.5rem;
}

h2 {
    font-size: 1.8rem;
    color: var(--accent-blue);
    margin-top: 3rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

h3 {
    font-size: 1.4rem;
    color: var(--accent-cyan);
    margin-top: 2rem;
}

h4 {
    font-size: 1.2rem;
    color: var(--accent-green);
    margin-top: 1.5rem;
}

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

/* Links */
a {
    color: var(--accent-blue);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--accent-purple);
    text-decoration: underline;
}

/* Cards */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.card-title {
    font-size: 1.2rem;
    color: var(--text-primary);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.card-title .icon {
    font-size: 1.4rem;
}

/* Definition Box */
.definition-box {
    background: linear-gradient(135deg, rgba(88, 166, 255, 0.1), rgba(163, 113, 247, 0.1));
    border-left: 4px solid var(--accent-blue);
    padding: 20px 24px;
    margin: 20px 0;
    border-radius: 0 12px 12px 0;
}

.definition-box h4 {
    color: var(--accent-blue);
    margin-top: 0;
    margin-bottom: 10px;
}

/* Example Box */
.example-box {
    background: rgba(63, 185, 80, 0.1);
    border-left: 4px solid var(--accent-green);
    padding: 20px 24px;
    margin: 20px 0;
    border-radius: 0 12px 12px 0;
}

.example-box h4 {
    color: var(--accent-green);
    margin-top: 0;
    margin-bottom: 10px;
}

.example-box .label {
    background: var(--accent-green);
    color: var(--bg-primary);
    padding: 2px 10px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    margin-bottom: 10px;
    display: inline-block;
}

/* Important Box */
.important-box {
    background: rgba(210, 153, 34, 0.1);
    border-left: 4px solid var(--accent-orange);
    padding: 20px 24px;
    margin: 20px 0;
    border-radius: 0 12px 12px 0;
}

.important-box h4 {
    color: var(--accent-orange);
    margin-top: 0;
    margin-bottom: 10px;
}

/* Warning Box */
.warning-box {
    background: rgba(248, 81, 73, 0.1);
    border-left: 4px solid var(--accent-red);
    padding: 20px 24px;
    margin: 20px 0;
    border-radius: 0 12px 12px 0;
}

.warning-box h4 {
    color: var(--accent-red);
    margin-top: 0;
    margin-bottom: 10px;
}

/* Formula Box */
.formula-box {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    padding: 20px 24px;
    margin: 20px 0;
    border-radius: 12px;
    text-align: center;
    font-size: 1.2rem;
    font-family: 'Cambria Math', 'Times New Roman', serif;
}

.formula-box .formula {
    color: var(--accent-cyan);
    padding: 10px;
    display: block;
}

/* Code Blocks */
.code-block {
    background: var(--code-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 16px 20px;
    margin: 16px 0;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.95rem;
    overflow-x: auto;
    color: var(--text-primary);
}

code {
    background: var(--bg-tertiary);
    padding: 2px 8px;
    border-radius: 4px;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.9em;
    color: var(--accent-cyan);
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    background: var(--bg-card);
    border-radius: 12px;
    overflow: hidden;
}

th, td {
    padding: 14px 18px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 0.5px;
}

td {
    color: var(--text-secondary);
}

tr:last-child td {
    border-bottom: none;
}

tr:hover td {
    background: var(--highlight-bg);
}

/* Diagrams Container */
.diagram-container {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 30px;
    margin: 24px 0;
    text-align: center;
    overflow-x: auto;
}

.diagram-container svg {
    max-width: 100%;
    height: auto;
}

.diagram-caption {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 12px;
    font-style: italic;
}

/* State Machine Diagram Styles */
.state {
    fill: var(--bg-secondary);
    stroke: var(--accent-blue);
    stroke-width: 2;
}

.state-final {
    fill: var(--bg-secondary);
    stroke: var(--accent-green);
    stroke-width: 2;
}

.state-label {
    fill: var(--text-primary);
    font-size: 14px;
    text-anchor: middle;
    dominant-baseline: middle;
}

.transition {
    stroke: var(--text-secondary);
    stroke-width: 1.5;
    fill: none;
    marker-end: url(#arrowhead);
}

.transition-label {
    fill: var(--accent-cyan);
    font-size: 12px;
}

/* Question Answer Section */
.qa-section {
    margin: 30px 0;
}

.question {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    margin-bottom: 16px;
    overflow: hidden;
}

.question-header {
    background: var(--bg-tertiary);
    padding: 16px 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.2s;
}

.question-header:hover {
    background: var(--highlight-bg);
}

.question-text {
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 12px;
}

.question-marks {
    background: var(--accent-purple);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.question-toggle {
    color: var(--accent-blue);
    font-size: 1.2rem;
    transition: transform 0.3s;
}

.question.open .question-toggle {
    transform: rotate(180deg);
}

.answer {
    padding: 20px;
    display: none;
    border-top: 1px solid var(--border-color);
}

.question.open .answer {
    display: block;
}

/* Topic Navigation */
.topic-nav {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 30px;
    position: sticky;
    top: 80px;
}

.topic-nav h3 {
    color: var(--text-primary);
    margin-top: 0;
    margin-bottom: 15px;
    font-size: 1rem;
}

.topic-nav ul {
    list-style: none;
}

.topic-nav li {
    margin-bottom: 8px;
}

.topic-nav a {
    color: var(--text-secondary);
    font-size: 0.95rem;
    display: block;
    padding: 8px 12px;
    border-radius: 6px;
    transition: all 0.2s;
}

.topic-nav a:hover {
    background: var(--bg-tertiary);
    color: var(--accent-blue);
    text-decoration: none;
}

.topic-nav a.active {
    background: var(--highlight-bg);
    color: var(--accent-blue);
}

/* Layout for content with sidebar */
.content-wrapper {
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 40px;
}

.main-content {
    min-width: 0;
}

/* Lists */
ul, ol {
    margin: 16px 0;
    padding-left: 24px;
    color: var(--text-secondary);
}

li {
    margin-bottom: 8px;
}

li::marker {
    color: var(--accent-blue);
}

/* Tuple Representation */
.tuple {
    font-family: 'Cambria Math', 'Times New Roman', serif;
    font-size: 1.1rem;
    color: var(--accent-cyan);
    padding: 4px 8px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    display: inline-block;
    margin: 4px 0;
}

/* Transition Table */
.transition-table {
    font-family: 'Consolas', monospace;
}

.transition-table th:first-child,
.transition-table td:first-child {
    text-align: center;
    font-weight: 600;
    color: var(--accent-blue);
}

/* Step by Step Process */
.step-process {
    counter-reset: step;
}

.step {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px 24px 20px 70px;
    margin-bottom: 16px;
    position: relative;
}

.step::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: 20px;
    top: 20px;
    width: 32px;
    height: 32px;
    background: var(--accent-blue);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
}

.step h4 {
    margin-top: 0;
    color: var(--text-primary);
}

/* Tabs */
.tabs {
    display: flex;
    border-bottom: 2px solid var(--border-color);
    margin-bottom: 20px;
}

.tab {
    padding: 12px 24px;
    cursor: pointer;
    color: var(--text-secondary);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all 0.2s;
}

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

.tab.active {
    color: var(--accent-blue);
    border-bottom-color: var(--accent-blue);
}

.tab-content {
    display: none;
}

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

/* Progress Bar */
.progress-container {
    background: var(--bg-tertiary);
    border-radius: 10px;
    height: 8px;
    overflow: hidden;
    margin: 20px 0;
}

.progress-bar {
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
    height: 100%;
    border-radius: 10px;
    transition: width 0.5s ease;
}

/* Footer */
footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 30px 0;
    margin-top: 60px;
    text-align: center;
}

footer p {
    color: var(--text-muted);
    margin: 0;
}

/* Index Page Specific */
.hero {
    text-align: center;
    padding: 60px 0;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 2rem;
}

.module-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-top: 40px;
}

.module-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 30px;
    text-decoration: none;
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.module-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-purple));
    transform: scaleX(0);
    transition: transform 0.3s;
}

.module-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow);
    text-decoration: none;
}

.module-card:hover::before {
    transform: scaleX(1);
}

.module-number {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 15px;
}

.module-card h3 {
    color: var(--text-primary);
    margin-top: 0;
    margin-bottom: 12px;
    font-size: 1.3rem;
}

.module-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin: 0;
}

.module-topics {
    margin-top: 15px;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.topic-tag {
    background: var(--bg-tertiary);
    color: var(--text-muted);
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 0.75rem;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--border-color);
}

/* Highlight Animation */
@keyframes highlight {
    0% { background-color: var(--highlight-bg); }
    100% { background-color: transparent; }
}

.highlight-animation {
    animation: highlight 2s ease-out;
}

/* Responsive adjustments for smaller desktops */
@media (max-width: 1100px) {
    .module-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .content-wrapper {
        grid-template-columns: 200px 1fr;
        gap: 30px;
    }
}

@media (max-width: 800px) {
    .content-wrapper {
        grid-template-columns: 1fr;
    }

    .topic-nav {
        position: static;
    }
}