/* Applied Physics Mini-Book - Common Styles */
/* Dark Mode Theme with High Readability */

:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --bg-card: #1c2128;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --accent-blue: #58a6ff;
    --accent-green: #3fb950;
    --accent-purple: #a371f7;
    --accent-orange: #f0883e;
    --accent-red: #f85149;
    --accent-cyan: #39c5cf;
    --accent-yellow: #d29922;
    --border-color: #30363d;
    --highlight-bg: #1f2937;
    --formula-bg: #1a1f2e;
    --example-bg: #0f1a0f;
    --note-bg: #1a1a0f;
    --diagram-bg: #12161c;
}

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

html {
    font-size: 20px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.8;
    min-height: 100vh;
}

/* Main Content Container */
.content {
    width: 100%;
    max-width: 100%;
    padding: 2rem 4rem;
}

/* Module Title */
.module-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-blue);
    text-align: center;
    padding: 2rem 0;
    margin-bottom: 2rem;
    border-bottom: 3px solid var(--accent-blue);
    background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}

/* Section Styling */
.section {
    margin-bottom: 3rem;
    padding: 2rem;
    background-color: var(--bg-secondary);
    border-radius: 12px;
    border-left: 5px solid var(--accent-blue);
}

.section-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

.subsection-title {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--accent-purple);
    margin: 1.5rem 0 1rem 0;
}

/* Paragraphs */
p {
    font-size: 1.1rem;
    margin-bottom: 1rem;
    text-align: justify;
}

/* Lists */
ul, ol {
    margin: 1rem 0 1.5rem 2rem;
    font-size: 1.1rem;
}

li {
    margin-bottom: 0.8rem;
    padding-left: 0.5rem;
}

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

ol li::marker {
    color: var(--accent-orange);
    font-weight: bold;
}

/* Definition Lists */
.definition {
    background-color: var(--bg-tertiary);
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1rem 0;
    border-left: 4px solid var(--accent-purple);
}

.definition-term {
    font-weight: 600;
    color: var(--accent-cyan);
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.definition-desc {
    color: var(--text-primary);
    font-size: 1.1rem;
}

/* Formula Box */
.formula-box {
    background: linear-gradient(135deg, var(--formula-bg) 0%, #1e2740 100%);
    border: 2px solid var(--accent-blue);
    border-radius: 10px;
    padding: 1.5rem 2rem;
    margin: 1.5rem 0;
    text-align: center;
}

.formula-box .formula {
    font-size: 1.4rem;
    color: var(--accent-yellow);
    font-family: 'Cambria Math', 'Times New Roman', serif;
    font-weight: 500;
    letter-spacing: 1px;
}

.formula-box .formula-name {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
    font-style: italic;
}

/* Multiple Formulas Container */
.formulas-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 1.5rem 0;
}

/* Example Box */
.example-box {
    background: linear-gradient(135deg, var(--example-bg) 0%, #0a1f0a 100%);
    border: 2px solid var(--accent-green);
    border-radius: 10px;
    padding: 2rem;
    margin: 2rem 0;
}

.example-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--accent-green);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.example-title::before {
    content: "✎";
    font-size: 1.2rem;
}

.example-problem {
    background-color: rgba(0, 0, 0, 0.3);
    padding: 1rem 1.5rem;
    border-radius: 6px;
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
    border-left: 3px solid var(--accent-orange);
}

.example-solution {
    padding-top: 1rem;
}

.solution-step {
    margin: 1rem 0;
    padding: 0.8rem 1rem;
    background-color: rgba(255, 255, 255, 0.03);
    border-radius: 6px;
}

.step-label {
    font-weight: 600;
    color: var(--accent-cyan);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.step-content {
    font-size: 1.1rem;
    color: var(--text-primary);
}

.step-formula {
    font-family: 'Cambria Math', 'Times New Roman', serif;
    color: var(--accent-yellow);
    font-size: 1.2rem;
    background-color: rgba(0, 0, 0, 0.3);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    display: inline-block;
    margin: 0.5rem 0;
}

.final-answer {
    background: linear-gradient(90deg, rgba(63, 185, 80, 0.2) 0%, transparent 100%);
    border-left: 4px solid var(--accent-green);
    padding: 1rem 1.5rem;
    margin-top: 1rem;
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-green);
}

/* Note Box */
.note-box {
    background: linear-gradient(135deg, var(--note-bg) 0%, #1f1a0a 100%);
    border: 2px solid var(--accent-yellow);
    border-radius: 10px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.note-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent-yellow);
    margin-bottom: 0.8rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.note-title::before {
    content: "📌";
}

.note-content {
    font-size: 1.05rem;
    color: var(--text-primary);
}

/* Important Box */
.important-box {
    background: linear-gradient(135deg, #1f0f0f 0%, #2a1010 100%);
    border: 2px solid var(--accent-red);
    border-radius: 10px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.important-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--accent-red);
    margin-bottom: 0.8rem;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    font-size: 1.05rem;
    background-color: var(--bg-tertiary);
    border-radius: 8px;
    overflow: hidden;
}

thead {
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
}

th {
    padding: 1rem 1.5rem;
    text-align: left;
    font-weight: 600;
    color: white;
    font-size: 1.1rem;
}

td {
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

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

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

tr:hover {
    background-color: rgba(88, 166, 255, 0.1);
}

/* Diagram Container */
.diagram-container {
    background-color: var(--diagram-bg);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    margin: 2rem 0;
    text-align: center;
}

.diagram-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 1.5rem;
}

.diagram {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 200px;
}

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

.diagram-caption {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-top: 1rem;
    font-style: italic;
}

/* Flow Chart */
.flow-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    margin: 2rem 0;
    padding: 2rem;
    background-color: var(--bg-tertiary);
    border-radius: 12px;
}

.flow-step {
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
    color: white;
    padding: 1rem 2rem;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 500;
    text-align: center;
    min-width: 300px;
}

.flow-arrow {
    font-size: 1.5rem;
    color: var(--accent-cyan);
}

/* Comparison Table */
.comparison-table {
    margin: 2rem 0;
}

.comparison-table th:first-child {
    background: var(--bg-tertiary);
    color: var(--accent-cyan);
}

/* Key Points List */
.key-points {
    background-color: var(--bg-tertiary);
    padding: 1.5rem 2rem;
    border-radius: 10px;
    margin: 1.5rem 0;
}

.key-points-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-green);
    margin-bottom: 1rem;
}

.key-points ul {
    list-style: none;
    margin: 0;
}

.key-points li {
    position: relative;
    padding-left: 2rem;
    margin-bottom: 0.8rem;
}

.key-points li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--accent-green);
    font-weight: bold;
}

/* Inline Formula */
.inline-formula {
    font-family: 'Cambria Math', 'Times New Roman', serif;
    color: var(--accent-yellow);
    background-color: rgba(210, 153, 34, 0.15);
    padding: 0.1rem 0.5rem;
    border-radius: 4px;
    font-size: 1.1em;
}

/* Highlight Text */
.highlight {
    background: linear-gradient(120deg, rgba(88, 166, 255, 0.3) 0%, rgba(163, 113, 247, 0.3) 100%);
    padding: 0.1rem 0.4rem;
    border-radius: 3px;
}

/* Term Definition */
.term {
    color: var(--accent-cyan);
    font-weight: 600;
}

/* Units */
.unit {
    color: var(--accent-orange);
    font-style: italic;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 12px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--bg-tertiary);
    border-radius: 6px;
    border: 2px solid var(--bg-secondary);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-blue);
}

/* Selection */
::selection {
    background-color: var(--accent-blue);
    color: white;
}

/* Index Page Specific */
.index-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.index-title {
    font-size: 3rem;
    font-weight: 700;
    color: var(--accent-blue);
    text-align: center;
    margin-bottom: 1rem;
}

.index-subtitle {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    text-align: center;
}

.modules-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    max-width: 1400px;
    width: 100%;
}

.module-card {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    border: 2px solid var(--border-color);
    border-radius: 16px;
    padding: 2rem;
    text-decoration: none;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

.module-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-5px);
    box-shadow: 0 10px 40px rgba(88, 166, 255, 0.2);
}

.module-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--accent-purple);
    opacity: 0.5;
    margin-bottom: 0.5rem;
}

.module-name {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.module-topics {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.6;
    flex-grow: 1;
}

/* Module Links */
.module-links {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.module-link {
    flex: 1;
    padding: 0.8rem 1rem;
    background-color: var(--bg-tertiary);
    color: var(--accent-blue);
    text-decoration: none;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.module-link:hover {
    background-color: var(--accent-blue);
    color: white;
    transform: translateY(-2px);
}

.module-link.questions-link {
    color: var(--accent-green);
}

.module-link.questions-link:hover {
    background-color: var(--accent-green);
    color: white;
}

/* Two Column Layout */
.two-column {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: 1.5rem 0;
}

/* Three Column Layout */
.three-column {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin: 1.5rem 0;
}

/* Card Style */
.card {
    background-color: var(--bg-tertiary);
    border-radius: 10px;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

.card-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 1rem;
}

/* Process Steps */
.process-steps {
    counter-reset: step;
    margin: 1.5rem 0;
}

.process-step {
    position: relative;
    padding-left: 4rem;
    padding-bottom: 2rem;
    border-left: 3px solid var(--border-color);
    margin-left: 1.5rem;
}

.process-step:last-child {
    border-left: 3px solid transparent;
    padding-bottom: 0;
}

.process-step::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: -1.5rem;
    top: 0;
    width: 3rem;
    height: 3rem;
    background: linear-gradient(135deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    color: white;
}

.process-step-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 0.5rem;
}

.process-step-content {
    font-size: 1.05rem;
    color: var(--text-primary);
}

/* Symbol styling */
.symbol {
    font-family: 'Cambria Math', 'Times New Roman', serif;
    font-style: italic;
    color: var(--accent-yellow);
}

/* Fraction display */
.fraction {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    vertical-align: middle;
    font-family: 'Cambria Math', 'Times New Roman', serif;
}

.fraction .num {
    border-bottom: 2px solid var(--accent-yellow);
    padding: 0 0.3rem;
}

.fraction .den {
    padding: 0 0.3rem;
}

/* Back link */
.back-link {
    display: inline-block;
    margin: 1rem 2rem;
    padding: 0.8rem 1.5rem;
    background-color: var(--bg-tertiary);
    color: var(--accent-blue);
    text-decoration: none;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.back-link:hover {
    background-color: var(--accent-blue);
    color: white;
}

/* Application Box */
.application-box {
    background: linear-gradient(135deg, #0f1a1f 0%, #0a1520 100%);
    border: 2px solid var(--accent-cyan);
    border-radius: 10px;
    padding: 2rem;
    margin: 2rem 0;
}

.application-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--accent-cyan);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.application-title::before {
    content: "⚡";
}

/* Derivation Box */
.derivation-box {
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 2rem;
    margin: 1.5rem 0;
}

.derivation-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--accent-purple);
    margin-bottom: 1.5rem;
}

.derivation-step {
    margin: 1rem 0;
    padding: 0.5rem 0;
}

/* Energy Level Diagram Styles */
.energy-diagram {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    padding: 2rem;
}

.energy-level {
    width: 200px;
    height: 4px;
    background-color: var(--accent-blue);
    position: relative;
}

.energy-label {
    position: absolute;
    right: -120px;
    top: -10px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Vector notation */
.vector {
    font-weight: bold;
    color: var(--accent-orange);
}

/* Equation numbering */
.equation-numbered {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    background-color: var(--formula-bg);
    border-radius: 6px;
    margin: 0.5rem 0;
}

.equation-number {
    color: var(--text-muted);
    font-size: 0.9rem;
}