/* Matty - Mathematical Visualizations Styles */
/* Mathematical/Graph Paper Theme */

@import url('https://fonts.googleapis.com/css2?family=Computer+Modern+Serif&family=Computer+Modern+Sans:wght@400;700&family=Latin+Modern+Math&display=swap');
@import url('https://fonts.googleapis.com/css2?family=Crimson+Text:ital,wght@0,400;0,600;1,400&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
    /* Paper Colors - Dark Graph Paper Theme */
    --color-paper: #1a1a1f;
    --color-paper-dark: #25252a;
    --color-paper-lines: #2a2a2f;
    --color-paper-major: #333338;
    
    /* Ink Colors - Light text on dark */
    --color-ink-primary: #e8e8e3;
    --color-ink-secondary: #d0d0cb;
    --color-ink-tertiary: #b8b8b3;
    --color-ink-muted: #999999;
    
    /* Graph Colors - Bright colors for dark background */
    --color-graph-blue: #4a9eff;
    --color-graph-red: #ff4a4a;
    --color-graph-green: #4aff4a;
    --color-graph-purple: #9a4aff;
    --color-graph-orange: #ff9a4a;
    
    /* Border Colors */
    --color-border: #444449;
    --color-border-dark: #55555a;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* Shadows - Paper-like */
    --shadow-paper: 0 2px 4px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.08);
    --shadow-paper-raised: 0 4px 8px rgba(0, 0, 0, 0.12), 0 2px 4px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Crimson Text', 'Computer Modern Serif', serif;
    background: var(--color-paper);
    /* Graph paper pattern - fixed so it doesn't scroll */
    background-image: 
        linear-gradient(var(--color-paper-lines) 1px, transparent 1px),
        linear-gradient(90deg, var(--color-paper-lines) 1px, transparent 1px);
    background-size: 20px 20px;
    background-position: 0 0, 0 0;
    background-attachment: fixed;
    color: var(--color-ink-primary);
    line-height: 1.8;
    min-height: 100vh;
    position: relative;
}

/* Graph paper major lines overlay - also fixed */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(var(--color-paper-major) 1px, transparent 1px),
        linear-gradient(90deg, var(--color-paper-major) 1px, transparent 1px);
    background-size: 100px 100px;
    background-attachment: fixed;
    pointer-events: none;
    opacity: 0.6;
    z-index: 0;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-lg);
    position: relative;
    z-index: 1;
}

/* Header */
.header {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: var(--spacing-md) 0;
    margin-bottom: var(--spacing-md);
    background: var(--color-paper);
    border-bottom: 2px solid var(--color-border-dark);
    margin: calc(-1 * var(--spacing-lg)) calc(-1 * var(--spacing-lg)) var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    box-shadow: var(--shadow-paper);
    position: relative;
}

.header::after {
    content: 'f(x)';
    position: absolute;
    top: 15px;
    right: 30px;
    font-family: 'Latin Modern Math', 'Computer Modern Serif', serif;
    font-size: 1.2rem;
    color: var(--color-ink-muted);
    opacity: 0.3;
    font-style: italic;
}

.logo {
    font-size: 2.5rem;
    font-weight: 600;
    font-family: 'Computer Modern Sans', 'Crimson Text', serif;
    color: var(--color-graph-blue);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    position: relative;
    display: inline-block;
    margin: 0;
}

.logo::before,
.logo::after {
    content: '';
    position: absolute;
    width: 40px;
    height: 2px;
    background: var(--color-graph-blue);
    top: 50%;
}

.logo::before {
    left: -55px;
}

.logo::after {
    right: -55px;
}

.tagline {
    font-size: 0.9rem;
    color: var(--color-ink-tertiary);
    font-weight: 400;
    font-style: italic;
    letter-spacing: 0.02em;
    margin-top: var(--spacing-xs);
    margin-bottom: 0;
}

/* Main Toggle Navigation */
.main-toggle-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.main-toggle-btn {
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--color-paper-dark);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    color: var(--color-ink-primary);
    font-family: 'Computer Modern Sans', sans-serif;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-xs);
    box-shadow: var(--shadow-paper);
    text-align: left;
}

.main-toggle-btn:hover {
    background: var(--color-paper);
    border-color: var(--color-graph-blue);
}

.main-toggle-btn.active {
    background: var(--color-graph-blue);
    border-color: var(--color-graph-blue);
    color: white;
    box-shadow: var(--shadow-paper-raised);
}

.main-toggle-btn i {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-xs);
}

.toggle-btn-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    width: 100%;
}

.toggle-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin: 0;
    font-family: 'Computer Modern Sans', sans-serif;
}

.toggle-subtitle {
    font-size: 0.85rem;
    color: var(--color-ink-tertiary);
    font-style: italic;
    margin: 0;
    opacity: 0.9;
}

.main-toggle-btn.active .toggle-subtitle {
    color: rgba(255, 255, 255, 0.9);
}


/* Section Titles */
.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-ink-primary);
    font-family: 'Computer Modern Sans', sans-serif;
    text-align: center;
    position: relative;
    padding-bottom: var(--spacing-xs);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 2px;
    background: var(--color-graph-blue);
}

.section-subtitle {
    text-align: center;
    color: var(--color-ink-tertiary);
    font-size: 0.95rem;
    margin-bottom: var(--spacing-lg);
    font-style: italic;
}

/* Equations Section */
.equations-section {
    margin-bottom: var(--spacing-xxl);
    padding: 0;
}

.categories-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-top: 0;
}

.category-card {
    background: var(--color-paper);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    box-shadow: var(--shadow-paper-raised);
    position: relative;
    width: 100%;
}

.category-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-paper-dark);
    border-bottom: 1px solid var(--color-border);
}

.category-icon {
    font-size: 1rem;
    color: var(--color-graph-blue);
    width: 20px;
    text-align: center;
}

.category-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-ink-primary);
    font-family: 'Computer Modern Sans', sans-serif;
    flex: 1;
    margin: 0;
    border: none;
    padding: 0;
}

.category-title::after {
    display: none;
}

.category-toggle {
    color: var(--color-graph-blue);
    font-size: 0.75rem;
    transition: transform 0.2s ease;
}

.equations-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
}

.equation-item {
    background: var(--color-paper-dark);
    border: 1px solid var(--color-border);
    border-radius: 0;
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    align-items: stretch;
}

.illustration-container {
    width: 100%;
    height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-paper);
    border: 1px solid var(--color-border);
    margin-bottom: var(--spacing-xs);
}

.equation-illustration {
    width: 100%;
    height: 100%;
}

.equation-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.equation-name {
    font-size: 1rem;
    font-weight: 600;
    color: var(--color-graph-blue);
    font-family: 'Computer Modern Sans', sans-serif;
    margin: 0;
}

.equation-formula {
    font-size: 1.1rem;
    font-family: 'Latin Modern Math', 'Crimson Text', serif;
    color: var(--color-ink-primary);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-paper);
    border: 1px solid var(--color-border-dark);
    text-align: center;
    overflow-x: auto;
    overflow-y: hidden;

    scrollbar-width: thin;
    scrollbar-color: var(--color-graph-blue) var(--color-paper);
}

.equation-formula .katex {
    font-size: 1.1rem;
}

.equation-formula .katex-display {
    margin: 0;
}

.equation-description {
    font-size: 0.85rem;
    color: var(--color-ink-tertiary);
    font-style: italic;
    line-height: 1.5;
    margin: 0;
}

/* Graph Generator Section */
.graph-generator-section {
    margin-top: 0;
    padding: 0;
    border-top: none;
}

/* Category Navigation */
.category-nav {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
    padding: var(--spacing-sm);
    background: var(--color-paper-dark);
    border: 2px solid var(--color-border);
    border-radius: 0;
    box-shadow: var(--shadow-paper);
}

.category-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-paper);
    border: 1px solid var(--color-border-dark);
    border-radius: 0;
    color: var(--color-ink-primary);
    font-size: 0.9rem;
    font-weight: 600;
    font-family: 'Computer Modern Sans', sans-serif;
    cursor: pointer;
    transition: all 0.2s ease;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    position: relative;
    box-shadow: var(--shadow-paper);
}

.category-btn::before {
    content: '→';
    position: absolute;
    left: -20px;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.category-btn:hover {
    background: var(--color-paper-dark);
    border-color: var(--color-graph-blue);
    transform: translateX(5px);
}

.category-btn:hover::before {
    opacity: 1;
}

.category-btn.active {
    background: var(--color-graph-blue);
    border-color: var(--color-graph-blue);
    color: white;
    box-shadow: var(--shadow-paper-raised);
    transform: translateX(0);
}

.category-btn.active::before {
    opacity: 0;
}

/* Fun Button - Special POW Effect */
.category-btn[data-category="fun"] {
    background: linear-gradient(135deg, var(--color-graph-purple), var(--color-graph-orange));
    border: 2px solid var(--color-graph-orange);
    color: white;
    font-weight: 700;
    text-shadow: 0 0 10px rgba(255, 154, 74, 0.8);
    animation: funPulse 2s ease-in-out infinite;
    position: relative;
    overflow: visible;
}

.category-btn[data-category="fun"]::after {
    content: '✨';
    position: absolute;
    top: -8px;
    right: -8px;
    font-size: 1.2rem;
    animation: sparkle 1.5s ease-in-out infinite;
    z-index: 10;
}

.category-btn[data-category="fun"]:hover {
    background: linear-gradient(135deg, var(--color-graph-orange), var(--color-graph-purple));
    border-color: var(--color-graph-purple);
    transform: translateX(5px) scale(1.05);
    box-shadow: 0 0 20px rgba(154, 74, 255, 0.6), 0 0 40px rgba(255, 154, 74, 0.4);
}

.category-btn[data-category="fun"].active {
    background: linear-gradient(135deg, var(--color-graph-orange), var(--color-graph-purple), var(--color-graph-green));
    background-size: 200% 200%;
    border-color: var(--color-graph-orange);
    animation: funActive 1.5s ease-in-out infinite, funPulse 2s ease-in-out infinite;
    box-shadow: 0 0 25px rgba(255, 154, 74, 0.8), 0 0 50px rgba(154, 74, 255, 0.6);
}

.category-btn[data-category="fun"].active::after {
    animation: sparkleActive 0.8s ease-in-out infinite;
}

@keyframes funPulse {
    0%, 100% {
        box-shadow: 0 0 10px rgba(255, 154, 74, 0.4), var(--shadow-paper);
    }
    50% {
        box-shadow: 0 0 20px rgba(255, 154, 74, 0.6), 0 0 30px rgba(154, 74, 255, 0.4);
    }
}

@keyframes funActive {
    0%, 100% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
}

@keyframes sparkle {
    0%, 100% {
        opacity: 0.5;
        transform: scale(1) rotate(0deg);
    }
    50% {
        opacity: 1;
        transform: scale(1.2) rotate(180deg);
    }
}

@keyframes sparkleActive {
    0%, 100% {
        opacity: 1;
        transform: scale(1.3) rotate(0deg);
    }
    25% {
        transform: scale(1.5) rotate(90deg);
    }
    50% {
        transform: scale(1.3) rotate(180deg);
    }
    75% {
        transform: scale(1.5) rotate(270deg);
    }
}

/* Main Content */
.main-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

/* Graph Selection */
.graph-selection-section {
    background: var(--color-paper);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    padding: var(--spacing-sm);
    box-shadow: var(--shadow-paper-raised);
    position: relative;
}

.graph-selection-section::before {
    content: 'Graph Type:';
    position: absolute;
    top: -12px;
    left: 20px;
    background: var(--color-paper);
    padding: 0 var(--spacing-xs);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-ink-secondary);
    font-family: 'Computer Modern Sans', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.graph-selector {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.graph-selector label {
    font-weight: 600;
    color: var(--color-ink-primary);
    font-size: 1rem;
    font-family: 'Computer Modern Sans', sans-serif;
}

.graph-select {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-paper-dark);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    color: var(--color-ink-primary);
    font-size: 1rem;
    font-family: 'Crimson Text', serif;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.3);
}

.graph-select:hover {
    border-color: var(--color-graph-blue);
    background: var(--color-paper);
}

.graph-select:focus {
    outline: 2px solid var(--color-graph-blue);
    outline-offset: 2px;
}

/* Canvas Container */
.graph-display-section {
    background: var(--color-paper);
    border: 3px double var(--color-border-dark);
    border-radius: 0;
    padding: var(--spacing-sm);
    box-shadow: var(--shadow-paper-raised);
    position: relative;
}

.graph-display-section::before {
    content: 'Graph';
    position: absolute;
    top: -12px;
    left: 20px;
    background: var(--color-paper);
    padding: 0 var(--spacing-xs);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-ink-secondary);
    font-family: 'Computer Modern Sans', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.canvas-container {
    position: relative;
    width: 100%;
    background: #0f0f14;
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    overflow: hidden;
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.3);
}

#graphCanvas {
    display: block;
    width: 100%;
    height: 500px;
    cursor: crosshair;
    background: #0f0f14;
}

.canvas-controls {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    display: flex;
    gap: var(--spacing-xs);
    z-index: 10;
}

.control-btn {
    width: 36px;
    height: 36px;
    background: var(--color-paper);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    color: var(--color-ink-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-paper);
    font-size: 0.9rem;
}

.control-btn:hover {
    background: var(--color-graph-blue);
    border-color: var(--color-graph-blue);
    color: white;
    transform: scale(1.05);
}

/* Parameters and Explanation Section */
.params-explanation-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
}

/* Parameters Section */
.parameters-section {
    background: var(--color-paper);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    padding: var(--spacing-md);
    box-shadow: var(--shadow-paper-raised);
    position: relative;
}

.parameters-section::before {
    content: 'Parameters';
    position: absolute;
    top: -12px;
    left: 20px;
    background: var(--color-paper);
    padding: 0 var(--spacing-xs);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-ink-secondary);
    font-family: 'Computer Modern Sans', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.subsection-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-ink-primary);
    font-family: 'Computer Modern Sans', sans-serif;
    border-bottom: 1px solid var(--color-border-dark);
    padding-bottom: var(--spacing-xs);
}

.parameters-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.parameter-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.parameter-label {
    font-size: 0.95rem;
    color: var(--color-ink-primary);
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: 'Computer Modern Sans', sans-serif;
    margin-bottom: var(--spacing-xs);
}

.parameter-value {
    font-family: 'JetBrains Mono', monospace;
    color: var(--color-graph-blue);
    font-weight: 600;
    background: var(--color-paper-dark);
    padding: 2px 8px;
    border: 1px solid var(--color-border);
}

.parameter-input {
    width: 100%;
    padding: var(--spacing-xs);
    background: var(--color-bg-tertiary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    color: var(--color-text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.parameter-input:focus {
    outline: none;
    border-color: var(--color-graph-primary);
    box-shadow: 0 0 0 3px rgba(79, 156, 249, 0.1);
}

.parameter-slider {
    width: 100%;
    height: 8px;
    background: var(--color-paper-dark);
    border: 1px solid var(--color-border);
    border-radius: 0;
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.1);
}

.parameter-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--color-graph-blue);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-paper);
}

.parameter-slider::-webkit-slider-thumb:hover {
    background: var(--color-graph-red);
    transform: scale(1.1);
}

.parameter-slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--color-graph-blue);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-paper);
}

.parameter-slider::-moz-range-thumb:hover {
    background: var(--color-graph-red);
    transform: scale(1.1);
}

/* Equation Section */
.equation-section {
    background: var(--color-paper);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    padding: var(--spacing-sm);
    box-shadow: var(--shadow-paper-raised);
    position: relative;
}

.equation-section::before {
    content: 'Equation';
    position: absolute;
    top: -12px;
    left: 20px;
    background: var(--color-paper);
    padding: 0 var(--spacing-xs);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-ink-secondary);
    font-family: 'Computer Modern Sans', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.equation-section .section-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--color-ink-primary);
    font-family: 'Computer Modern Sans', sans-serif;
    border-bottom: 1px solid var(--color-border-dark);
    padding-bottom: var(--spacing-xs);
    display: inline-block;
    width: 100%;
}

.equation-section .section-title::after {
    display: none;
}

.equation-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.equation-display {
    background: var(--color-paper-dark);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    padding: var(--spacing-sm);
    font-family: 'Latin Modern Math', 'Crimson Text', serif;
    font-size: 1.1rem;
    color: var(--color-graph-blue);
    text-align: center;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    word-break: break-all;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.3);
    position: relative;
    overflow-x: auto;
    overflow-y: hidden;
}

.equation-display .katex {
    font-size: 1.2rem;
}

.equation-display .katex-display {
    margin: 0;
}

.equation-display::before {
    content: 'y =';
    position: absolute;
    left: 20px;
    color: var(--color-ink-muted);
    font-style: italic;
}

.equation-formats {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.format-btn {
    flex: 1;
    min-width: 100px;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--color-paper-dark);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    color: var(--color-ink-primary);
    font-size: 0.8rem;
    font-weight: 600;
    font-family: 'Computer Modern Sans', sans-serif;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    box-shadow: var(--shadow-paper);
}

.format-btn:hover {
    background: var(--color-paper-dark);
    border-color: var(--color-graph-blue);
}

.format-btn.active {
    background: var(--color-graph-blue);
    border-color: var(--color-graph-blue);
    color: white;
    box-shadow: var(--shadow-paper-raised);
}

.copy-btn {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--color-graph-blue);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    color: white;
    font-size: 0.9rem;
    font-weight: 600;
    font-family: 'Computer Modern Sans', sans-serif;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    box-shadow: var(--shadow-paper-raised);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.copy-btn:hover {
    background: var(--color-graph-red);
    transform: translateY(-1px);
    box-shadow: var(--shadow-paper);
}

.copy-btn:active {
    transform: translateY(0);
}

.copy-btn.copied {
    background: var(--color-graph-green);
    border-color: var(--color-graph-green);
}

/* Explanation Section */
.explanation-section {
    background: var(--color-paper);
    border: 2px solid var(--color-border-dark);
    border-radius: 0;
    padding: var(--spacing-md);
    box-shadow: var(--shadow-paper-raised);
    position: relative;
}

.explanation-section::before {
    content: 'Explanation';
    position: absolute;
    top: -12px;
    left: 20px;
    background: var(--color-paper);
    padding: 0 var(--spacing-xs);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-ink-secondary);
    font-family: 'Computer Modern Sans', sans-serif;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.explanation-content {
    color: var(--color-ink-primary);
    line-height: 1.6;
    font-size: 0.9rem;
}

.explanation-content h3 {
    color: var(--color-graph-blue);
    font-size: 1rem;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    font-family: 'Computer Modern Sans', sans-serif;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: var(--spacing-xs);
}

.explanation-content p {
    margin: 0;
    text-align: justify;
}

.explanation-content code {
    background: var(--color-paper-dark);
    padding: 0.2em 0.5em;
    border: 1px solid var(--color-border);
    border-radius: 0;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95em;
    color: var(--color-graph-blue);
    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.05);
}

/* Footer */
#footer {
    text-align: center;
    padding: var(--spacing-xl) 1rem;
    color: var(--color-ink-muted);
    font-size: 0.9rem;
    margin-top: var(--spacing-xxl);
    border-top: 2px solid var(--color-border);
    font-style: italic;
    position: relative;
}

#footer::before {
    content: '∞';
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 1.5rem;
    color: var(--color-ink-muted);
    opacity: 0.3;
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.footer-content p {
    margin: 0.25rem 0;
}

.footer-subtitle {
    font-size: 0.85rem;
    opacity: 0.8;
    font-style: italic;
}

.footer-links {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-links a {
    color: var(--color-ink-muted);
    text-decoration: none;
    transition: color 0.3s ease;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--color-ink-primary, #333);
    text-decoration: underline;
}

.footer-separator {
    opacity: 0.5;
}

.footer-copyright {
    margin-top: 1rem;
    font-size: 0.85rem;
    opacity: 0.7;
}

@media (max-width: 768px) {
    .footer-links {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .footer-separator {
        display: none;
    }
}

/* Responsive Design */
@media screen and (max-width: 768px) {
    .logo {
        font-size: 2rem;
    }
    
    .logo::before,
    .logo::after {
        width: 30px;
    }
    
    .logo::before {
        left: -40px;
    }
    
    .logo::after {
        right: -40px;
    }
    
    .header::after {
        font-size: 1rem;
        top: 12px;
        right: 20px;
    }
    
    .main-toggle-nav {
        grid-template-columns: 1fr;
        gap: var(--spacing-xs);
    }
    
    .main-toggle-btn {
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .toggle-title {
        font-size: 1.1rem;
    }
    
    .toggle-subtitle {
        font-size: 0.75rem;
    }
    
    .categories-grid {
        gap: var(--spacing-sm);
    }
    
    .equations-list {
        grid-template-columns: 1fr;
    }
    
    .illustration-container {
        height: 150px;
    }
    
    #graphCanvas {
        height: 400px;
    }
    
    .params-explanation-section {
        grid-template-columns: 1fr;
    }
    
    .parameters-container {
        gap: var(--spacing-xs);
    }
    
    .equation-formats {
        flex-direction: column;
    }
    
    .format-btn {
        width: 100%;
    }
    
    .category-nav {
        gap: var(--spacing-xs);
    }
    
    .category-btn {
        padding: var(--spacing-xs) var(--spacing-sm);
        font-size: 0.9rem;
    }
}

@media screen and (max-width: 480px) {
    .container {
        padding: var(--spacing-sm);
    }
    
    #graphCanvas {
        height: 300px;
    }
    
    .canvas-controls {
        top: var(--spacing-xs);
        right: var(--spacing-xs);
    }
    
    .control-btn {
        width: 32px;
        height: 32px;
        font-size: 0.8rem;
    }
    
    .category-card {
        padding: var(--spacing-md);
    }
    
    .equation-formula {
        font-size: 1rem;
    }
}