/* ================================
   CSS Variables & Theme
   ================================ */

:root {
    /* Brand Colors - CodeLeaf Green */
    --color-primary: #6D8E5F;
    --color-primary-light: #8BAA7A;
    --color-primary-dark: #556E49;
    --color-accent: #60a5fa;

    /* Light Mode */
    --color-bg: #FFFFFF;
    --color-bg-secondary: #F5F5F5;
    --color-bg-tertiary: #FAFAFA;
    --color-text: #1D1D1F;
    --color-text-secondary: #666666;
    --color-text-tertiary: #999999;
    --color-border: #E0E0E0;
    --color-shadow: rgba(0, 0, 0, 0.1);
    --color-shadow-strong: rgba(0, 0, 0, 0.15);

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6D8E5F 0%, #8BAA7A 100%);
    --gradient-hero: linear-gradient(135deg, #F5F5F5 0%, #FAFAFA 100%);
    --gradient-text: linear-gradient(135deg, #6D8E5F 0%, #60a5fa 100%);

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 1.5rem;
    --space-lg: 2rem;
    --space-xl: 3rem;
    --space-2xl: 4rem;
    --space-3xl: 6rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Typography */
    --font-system: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
}

[data-theme="dark"] {
    --color-bg: #1A1A1A;
    --color-bg-secondary: #242424;
    --color-bg-tertiary: #2A2A2A;
    --color-text: #FFFFFF;
    --color-text-secondary: #B0B0B0;
    --color-text-tertiary: #808080;
    --color-border: #3A3A3A;
    --color-shadow: rgba(0, 0, 0, 0.3);
    --color-shadow-strong: rgba(0, 0, 0, 0.5);
    --gradient-hero: linear-gradient(135deg, #1A1A1A 0%, #242424 100%);
}

/* ================================
   Reset & Base Styles
   ================================ */

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-system);
    font-weight: var(--font-weight-normal);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    text-decoration: none;
    color: inherit;
    transition: opacity var(--transition-fast);
}

a:hover {
    opacity: 0.8;
}

/* ================================
   Navigation
   ================================ */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: all var(--transition-normal);
}

[data-theme="dark"] .nav {
    background: rgba(26, 26, 26, 0.8);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--space-md) var(--space-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    width: 40px;
    height: 40px;
    flex-shrink: 0;
}

.logo-text {
    font-size: 1.75rem;
    font-weight: var(--font-weight-bold);
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-xs);
    border-radius: var(--radius-full);
    transition: transform var(--transition-fast);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    transform: scale(1.1);
}

.theme-icon {
    width: 20px;
    height: 20px;
    display: block;
}

.theme-icon svg {
    width: 100%;
    height: 100%;
    fill: var(--color-text-secondary);
    transition: fill var(--transition-fast);
}

.theme-toggle:hover .theme-icon svg {
    fill: var(--color-text);
}

/* ================================
   Apps Section
   ================================ */

.apps {
    padding: calc(80px + var(--space-3xl)) var(--space-lg) var(--space-3xl);
    background: var(--color-bg);
}

.apps-grid {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-xl);
}

.app-card {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
    opacity: 0;
    transform: translateY(30px);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.app-card.visible {
    animation: fadeInUp 0.6s ease-out forwards;
}

.app-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px var(--color-shadow);
}

.app-icon {
    width: 120px;
    height: 120px;
    border-radius: var(--radius-lg);
    margin-bottom: var(--space-lg);
    box-shadow: 0 8px 24px var(--color-shadow);
}

.app-name {
    font-size: 1.75rem;
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--space-sm);
}

.app-description {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-lg);
    line-height: 1.7;
    font-size: 1.125rem;
}

.app-screenshot {
    width: 100%;
    max-width: 280px;
    border-radius: var(--radius-md);
    box-shadow: 0 12px 32px var(--color-shadow-strong);
    margin: var(--space-lg) 0;
    transition: transform var(--transition-slow);
}

.app-card:hover .app-screenshot {
    transform: scale(1.05);
}

.app-links {
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    width: 100%;
    margin-top: auto;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: 0.875rem 1.75rem;
    border-radius: var(--radius-full);
    font-size: 1rem;
    font-weight: var(--font-weight-semibold);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: center;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 16px rgba(109, 142, 95, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 24px rgba(109, 142, 95, 0.4);
    opacity: 1;
}

.btn-secondary {
    background: transparent;
    color: var(--color-text);
    border: 2px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-bg-tertiary);
    border-color: var(--color-primary);
    opacity: 1;
}

.btn-icon {
    width: 20px;
    height: 20px;
}

/* ================================
   Footer
   ================================ */

.footer {
    background: var(--color-bg-secondary);
    padding: var(--space-xl) var(--space-lg);
    text-align: center;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer-text {
    color: var(--color-text-tertiary);
    font-size: 0.875rem;
}

/* ================================
   Animations
   ================================ */

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ================================
   Responsive Design
   ================================ */

@media (max-width: 768px) {
    .nav-container {
        padding: var(--space-md);
    }

    .apps {
        padding: calc(60px + var(--space-xl)) var(--space-md) var(--space-xl);
    }

    .apps-grid {
        grid-template-columns: 1fr;
        gap: var(--space-lg);
    }

    .app-icon {
        width: 100px;
        height: 100px;
    }

    .app-screenshot {
        max-width: 240px;
    }
}

/* Reduce motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}