/* ===========================
   CSS Variables & Reset
   =========================== */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-card: #1e293b;
    
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    
    --border-color: #334155;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    --transition: all 0.3s ease;
    --border-radius: 12px;
    --border-radius-sm: 8px;
    --border-radius-lg: 16px;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===========================
   Navigation
   =========================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    padding: 1rem 0;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    transition: var(--transition);
}

.logo-icon {
    font-size: 1.5rem;
}

.logo:hover {
    color: var(--primary-light);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-links a:hover {
    color: var(--primary-light);
}

.github-link {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    background: var(--bg-secondary);
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--border-color);
}

.github-link:hover {
    background: var(--bg-tertiary);
    border-color: var(--primary-color);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition);
}

/* ===========================
   Hero Section
   =========================== */
.hero {
    position: relative;
    padding: 140px 0 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    z-index: -1;
}

.hero-background::before {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.2) 0%, transparent 70%);
    top: -200px;
    right: -200px;
    animation: float 20s infinite alternate;
}

.hero-background::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(139, 92, 246, 0.2) 0%, transparent 70%);
    bottom: -100px;
    left: -100px;
    animation: float 15s infinite alternate-reverse;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 50px) scale(1.1); }
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-badge {
    display: inline-block;
    padding: 8px 20px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--primary-light);
    margin-bottom: 24px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 20px;
    background: linear-gradient(135deg, var(--primary-light) 0%, var(--secondary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-muted);
    line-height: 1.8;
    margin-bottom: 40px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 60px;
}

/* ===========================
   Buttons
   =========================== */
.btn {
    display: inline-flex;
    align-items: center;
    padding: 14px 32px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border-radius: var(--border-radius-sm);
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

/* ===========================
   Hero Stats
   =========================== */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
}

.stat {
    text-align: center;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-light);
    margin-bottom: 8px;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ===========================
   Sections
   =========================== */
.section {
    padding: 80px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-muted);
}

/* ===========================
   About Section
   =========================== */
.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.about-card {
    background: var(--bg-card);
    padding: 40px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.about-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.2);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.about-card h3 {
    font-size: 1.5rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.about-card p {
    color: var(--text-muted);
    line-height: 1.7;
}

/* ===========================
   Architectures Section
   =========================== */
.architectures-section {
    background: var(--bg-secondary);
}

.architectures-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.architecture-card {
    background: var(--bg-card);
    padding: 30px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.architecture-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.2);
}

.architecture-header {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 20px;
}

.architecture-icon {
    font-size: 2.5rem;
}

.architecture-header h3 {
    font-size: 1.25rem;
    color: var(--text-primary);
}

.badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    align-self: flex-start;
}

.badge-success {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success-color);
}

.badge-info {
    background: rgba(6, 182, 212, 0.2);
    color: var(--accent-color);
}

.badge-warning {
    background: rgba(245, 158, 11, 0.2);
    color: var(--warning-color);
}

.badge-primary {
    background: rgba(99, 102, 241, 0.2);
    color: var(--primary-light);
}

.badge-special {
    background: rgba(139, 92, 246, 0.2);
    color: var(--secondary-color);
}

.architecture-description {
    color: var(--text-muted);
    margin-bottom: 20px;
    line-height: 1.7;
}

.architecture-features {
    list-style: none;
    margin-bottom: 20px;
}

.architecture-features li {
    padding: 8px 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.architecture-files {
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    font-size: 0.875rem;
    color: var(--text-muted);
}

.architecture-files strong {
    color: var(--text-secondary);
}

/* ===========================
   Demo Section
   =========================== */
.demo-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 40px;
}

.demo-card {
    background: var(--bg-card);
    padding: 40px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.demo-icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.demo-card h3 {
    font-size: 1.75rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.demo-card p {
    color: var(--text-muted);
    margin-bottom: 24px;
    line-height: 1.7;
}

.code-block {
    background: var(--bg-primary);
    border-radius: var(--border-radius-sm);
    overflow: hidden;
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
}

.code-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    font-size: 0.875rem;
    color: var(--text-muted);
}

.copy-btn {
    padding: 4px 12px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.75rem;
    transition: var(--transition);
}

.copy-btn:hover {
    background: var(--primary-color);
    color: white;
}

.code-block pre {
    padding: 20px;
    overflow-x: auto;
}

.code-block code {
    font-family: 'JetBrains Mono', 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.comment {
    color: var(--text-muted);
    font-style: italic;
}

.demo-info {
    background: var(--bg-card);
    padding: 40px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.demo-info h4 {
    font-size: 1.125rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.demo-info p {
    color: var(--text-muted);
    margin-bottom: 24px;
    line-height: 1.7;
}

.demo-info code {
    background: var(--bg-primary);
    padding: 2px 8px;
    border-radius: 4px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.875rem;
    color: var(--primary-light);
}

/* ===========================
   Calculator Interface
   =========================== */
.calculator-interface {
    margin: 30px 0;
}

.calculator-input-group {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 20px;
}

.calculator-input-group label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.expression-input {
    padding: 14px 20px;
    background: var(--bg-primary);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.125rem;
    transition: var(--transition);
}

.expression-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.calculator-btn {
    width: 100%;
    padding: 14px 32px;
    font-size: 1rem;
}

.calculator-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.calculator-result {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    padding: 20px;
    margin-top: 20px;
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
}

.result-item:last-child {
    border-bottom: none;
}

.result-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
}

.result-value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--primary-light);
}

.calculator-error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: var(--border-radius-sm);
    padding: 16px;
    margin-top: 20px;
    color: #ef4444;
    font-size: 0.875rem;
}

.calculator-loading {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px;
    margin-top: 20px;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
}

.loading-spinner {
    width: 20px;
    height: 20px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.demo-divider {
    height: 1px;
    background: var(--border-color);
    margin: 40px 0 30px;
}

.demo-card h4 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

/* ===========================
   Documentation Section
   =========================== */
.documentation-section {
    background: var(--bg-secondary);
}

.documentation-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 24px;
}

.doc-card {
    background: var(--bg-card);
    padding: 32px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    text-decoration: none;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.doc-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.2);
}

.doc-icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.doc-card h3 {
    font-size: 1.25rem;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.doc-card p {
    color: var(--text-muted);
    margin-bottom: 16px;
    line-height: 1.7;
    flex-grow: 1;
}

.doc-link {
    color: var(--primary-light);
    font-weight: 600;
    font-size: 0.95rem;
}

/* ===========================
   Repository Structure
   =========================== */
.structure-content {
    max-width: 800px;
    margin: 0 auto;
}

.folder-tree {
    background: var(--bg-card);
    padding: 30px;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
}

.tree-item {
    display: flex;
    flex-direction: column;
    padding: 16px 0;
    border-bottom: 1px solid var(--border-color);
}

.tree-item:last-child {
    border-bottom: none;
}

.tree-item.folder {
    font-weight: 600;
    color: var(--primary-light);
}

.tree-item.file {
    color: var(--text-secondary);
}

.tree-item .icon {
    margin-right: 10px;
}

.tree-description {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: 4px;
    margin-left: 32px;
    font-weight: 400;
}

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

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    font-size: 1.25rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.footer-section h4 {
    font-size: 1rem;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.footer-section p {
    color: var(--text-muted);
    line-height: 1.7;
    margin-bottom: 16px;
}

.footer-social {
    display: flex;
    gap: 12px;
}

.footer-social a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--bg-tertiary);
    border-radius: var(--border-radius-sm);
    color: var(--text-secondary);
    transition: var(--transition);
}

.footer-social a:hover {
    background: var(--primary-color);
    color: white;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 12px;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--primary-light);
}

.footer-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.tag {
    padding: 6px 14px;
    background: var(--bg-tertiary);
    border-radius: 50px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
}

.footer-bottom p {
    margin: 4px 0;
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 1024px) {
    .demo-content {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr 1fr;
    }
    
    .architecture-card {
        padding: 24px;
    }
}

@media (max-width: 768px) {
    /* Navigation */
    .nav-links {
        position: fixed;
        top: 70px;
        right: -100%;
        background: var(--bg-secondary);
        width: 80%;
        max-width: 300px;
        height: calc(100vh - 70px);
        flex-direction: column;
        padding: 30px;
        box-shadow: -2px 0 10px rgba(0, 0, 0, 0.3);
        transition: right 0.3s ease;
        z-index: 999;
    }
    
    .nav-links.active {
        right: 0;
    }
    
    .nav-links a {
        padding: 12px 0;
        border-top: 1px solid var(--border-color); /* top boder for mobile nav bar */
        border-bottom: 1px solid var(--border-color);
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    /* Hero */
    .hero {
        min-height: 70vh;
        padding: 80px 0 60px;
    }
    
    .hero-title {
        font-size: 2.5rem;
        line-height: 1.2;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-buttons .btn {
        width: 100%;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 30px;
    }
    
    /* Grids */
    .about-grid,
    .architectures-grid,
    .documentation-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    /* Demo section */
    .demo-card {
        padding: 30px 20px;
    }
    
    .demo-info {
        padding: 30px 20px;
    }
    
    /* Calculator */
    .calculator-interface {
        margin: 20px 0;
    }
    
    .expression-input {
        font-size: 1rem;
        padding: 12px 16px;
    }
    
    .calculator-btn {
        padding: 12px 24px;
        font-size: 0.9rem;
    }
    
    /* Code blocks */
    .code-block {
        font-size: 0.85rem;
    }
    
    .code-block pre {
        padding: 16px;
    }
    
    /* Footer */
    .footer {
        padding: 40px 0 20px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    /* Section headers */
    .section-title {
        font-size: 2rem;
    }
    
    .section-subtitle {
        font-size: 1rem;
    }
    
    /* Architecture cards */
    .architecture-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
    
    .badge {
        align-self: flex-start;
    }
}

@media (max-width: 480px) {
    /* Container */
    .container {
        padding: 0 16px;
    }
    
    /* Hero */
    .hero {
        min-height: 60vh;
        padding: 60px 0 40px;
    }
    
    .hero-badge {
        font-size: 0.75rem;
        padding: 6px 14px;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .hero-description {
        font-size: 0.95rem;
    }
    
    /* Sections */
    .section {
        padding: 50px 0;
    }
    
    .section-header {
        margin-bottom: 30px;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    /* Cards */
    .about-card,
    .architecture-card,
    .doc-card,
    .demo-card,
    .demo-info {
        padding: 20px 16px;
    }
    
    .card-icon,
    .doc-icon,
    .demo-icon {
        font-size: 2rem;
    }
    
    /* Calculator */
    .calculator-interface {
        margin: 15px 0;
    }
    
    .calculator-input-group label {
        font-size: 0.8rem;
    }
    
    .expression-input {
        font-size: 0.95rem;
        padding: 10px 14px;
    }
    
    .calculator-btn {
        padding: 10px 20px;
        font-size: 0.85rem;
    }
    
    .result-label {
        font-size: 0.8rem;
    }
    
    .result-value {
        font-size: 1rem;
    }
    
    /* Code blocks */
    .code-block {
        font-size: 0.75rem;
        border-radius: 8px;
    }
    
    .code-block pre {
        padding: 12px;
        overflow-x: auto;
    }
    
    .code-header {
        padding: 8px 12px;
        font-size: 0.75rem;
    }
    
    .copy-btn {
        padding: 4px 10px;
        font-size: 0.7rem;
    }
    
    /* Architecture features */
    .architecture-features {
        font-size: 0.9rem;
    }
    
    .architecture-features li {
        padding-left: 24px;
    }
    
    /* Footer */
    .footer {
        padding: 30px 0 20px;
    }
    
    .footer-section h3 {
        font-size: 1.1rem;
    }
    
    .footer-section p {
        font-size: 0.9rem;
    }
    
    /* Buttons */
    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
    
    /* Tree structure */
    .folder-tree {
        font-size: 0.85rem;
    }
    
    .tree-item {
        padding: 8px 12px;
    }
}

/* Extra small devices (landscape phones) */
@media (max-width: 375px) {
    .hero-title {
        font-size: 1.5rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .calculator-interface {
        margin: 10px 0;
    }
    
    .expression-input,
    .calculator-btn {
        font-size: 0.85rem;
    }
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {
    /* Increase touch targets */
    .btn,
    .nav-links a,
    .footer-links a {
        min-height: 44px;
        display: inline-flex;
        align-items: center;
    }
    
    .calculator-btn {
        min-height: 48px;
    }
    
    /* Remove hover effects on touch devices */
    .about-card:hover,
    .architecture-card:hover,
    .doc-card:hover {
        transform: none;
    }
}