/**
 * Keto Meal Planner - Main Stylesheet
 * Professional, responsive, and accessible design
 */

/* ============================================
   CSS VARIABLES
   ============================================ */
:root {
    /* Colors */
    --color-primary: #10b981;      /* Green */
    --color-primary-dark: #059669;
    --color-secondary: #3b82f6;    /* Blue */
    --color-accent: #f59e0b;       /* Orange */

    --color-dark: #1f2937;
    --color-dark-light: #374151;
    --color-gray: #6b7280;
    --color-gray-light: #d1d5db;
    --color-gray-lighter: #f3f4f6;
    --color-white: #ffffff;

    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-info: #3b82f6;

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'Monaco', 'Courier New', monospace;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    --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);

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;

    /* Container */
    --container-max-width: 1280px;
    --container-padding: 1rem;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-dark);
    background-color: var(--color-white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-dark);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
}

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

a:hover {
    color: var(--color-primary-dark);
}

a:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

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

/* ============================================
   LAYOUT
   ============================================ */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Skip Link for Accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}

/* ============================================
   HEADER
   ============================================ */
.site-header {
    background: var(--color-white);
    border-bottom: 1px solid var(--color-gray-light);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 50;
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
}

/* Logo */
.logo a {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-dark);
    text-decoration: none;
}

.logo-icon {
    font-size: 2rem;
}

/* Navigation */
.main-navigation {
    display: flex;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-menu a {
    color: var(--color-dark);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.nav-menu a:hover {
    background: var(--color-gray-lighter);
    color: var(--color-primary);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: var(--spacing-sm);
    color: var(--color-dark);
}

/* Search Icon */
.header-search {
    display: flex;
    align-items: center;
}

.search-icon {
    padding: var(--spacing-sm);
    color: var(--color-dark);
    transition: color var(--transition-fast);
}

.search-icon:hover {
    color: var(--color-primary);
}

/* ============================================
   BREADCRUMBS
   ============================================ */
.breadcrumbs {
    background: var(--color-gray-lighter);
    padding: var(--spacing-md) 0;
    font-size: 0.875rem;
}

.breadcrumb-list {
    display: flex;
    list-style: none;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.breadcrumb-list a {
    color: var(--color-gray);
}

.breadcrumb-list a:hover {
    color: var(--color-primary);
}

/* ============================================
   MAIN CONTENT
   ============================================ */
main {
    min-height: 60vh;
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    padding: var(--spacing-3xl) 0;
    text-align: center;
}

.hero-title {
    font-size: 3rem;
    color: white;
    margin-bottom: var(--spacing-lg);
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-2xl);
    opacity: 0.95;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-2xl);
}

.hero-stats {
    display: flex;
    gap: var(--spacing-2xl);
    justify-content: center;
    flex-wrap: wrap;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.9;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    border: 2px solid transparent;
    transition: all var(--transition-base);
}

.btn-primary {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
    font-weight: 600;
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
    color: white;
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--color-secondary);
    color: white;
    border-color: var(--color-secondary);
    font-weight: 600;
}

.btn-secondary:hover {
    background: #2563eb;
    border-color: #2563eb;
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
    color: white;
}

.btn-secondary:active {
    transform: translateY(0);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background: transparent;
    color: white;
    border-color: white;
    font-weight: 600;
}

.btn-outline:hover {
    background: white;
    color: var(--color-primary);
    border-color: white;
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

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

.btn-link {
    color: var(--color-primary);
    font-weight: 600;
    transition: all var(--transition-base);
}

.btn-link:hover {
    color: var(--color-primary-dark);
    text-decoration: underline;
    transform: translateX(4px);
}

/* ============================================
   SECTIONS
   ============================================ */
section {
    padding: var(--spacing-3xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    font-size: 2.5rem;
    color: var(--color-dark);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--color-gray);
    margin-top: var(--spacing-sm);
}

.section-footer {
    text-align: center;
    margin-top: var(--spacing-xl);
}

/* ============================================
   RECIPE GRID
   ============================================ */
.recipe-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

.recipe-card {
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.recipe-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.recipe-image {
    position: relative;
    aspect-ratio: 4 / 3;
    overflow: hidden;
}

.recipe-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.recipe-badge {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 0.875rem;
}

.recipe-content {
    padding: var(--spacing-lg);
}

.recipe-title {
    font-size: 1.25rem;
    color: var(--color-dark);
    margin-bottom: var(--spacing-md);
}

.recipe-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: 0.875rem;
    color: var(--color-gray);
    margin-bottom: var(--spacing-sm);
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.375rem;
}

.meta-icon {
    color: var(--color-primary);
    flex-shrink: 0;
    transition: all 0.2s ease;
}

.meta-item:hover .meta-icon {
    transform: scale(1.15);
}

.recipe-category {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--color-gray-lighter);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-dark);
    text-transform: uppercase;
}

/* ============================================
   MEAL PLANS CTA
   ============================================ */
.meal-plans-cta {
    background: var(--color-gray-lighter);
    text-align: center;
}

.cta-title {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-lg);
}

.cta-text {
    font-size: 1.125rem;
    color: var(--color-gray);
    max-width: 700px;
    margin: 0 auto var(--spacing-2xl);
}

.calorie-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto;
}

.calorie-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: all var(--transition-base);
    text-decoration: none;
    color: var(--color-dark);
}

.calorie-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border: 2px solid var(--color-primary);
}

.calorie-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-sm);
}

.calorie-label {
    font-size: 1rem;
    color: var(--color-gray);
}

/* ============================================
   CATEGORIES
   ============================================ */
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.category-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: all var(--transition-base);
    text-decoration: none;
    color: var(--color-dark);
}

.category-card:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-4px);
}

.category-name {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.category-count {
    color: var(--color-gray);
    font-size: 0.875rem;
}

.category-card:hover .category-count {
    color: white;
    opacity: 0.9;
}

/* ============================================
   FEATURES
   ============================================ */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-2xl);
}

.feature-card {
    text-align: center;
    padding: var(--spacing-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
    transition: all 0.3s ease;
}

.feature-card:hover .feature-icon {
    transform: scale(1.1) rotate(5deg);
    color: var(--color-secondary);
}

.feature-icon svg {
    display: block;
    margin: 0 auto;
}

.feature-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
}

.feature-text {
    color: var(--color-gray);
}

/* ============================================
   FOOTER
   ============================================ */
.site-footer {
    background: var(--color-dark);
    color: white;
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-heading {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
}

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

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

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: var(--color-gray-light);
    transition: color var(--transition-fast);
}

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

.footer-bottom {
    border-top: 1px solid var(--color-dark-light);
    padding-top: var(--spacing-lg);
    text-align: center;
    color: var(--color-gray-light);
    font-size: 0.875rem;
}

.footer-stats {
    margin-top: var(--spacing-md);
}

/* ============================================
   BACK TO TOP
   ============================================ */
.back-to-top {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    background: var(--color-primary);
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    cursor: pointer;
    font-size: 1.5rem;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-base);
    z-index: 40;
}

.back-to-top:hover {
    background: var(--color-primary-dark);
    transform: translateY(-4px);
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 768px) {
    /* Mobile Navigation */
    .mobile-menu-toggle {
        display: block;
    }

    .main-navigation {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }

    .main-navigation.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-menu {
        flex-direction: column;
        padding: var(--spacing-lg);
    }

    /* Hero */
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-actions {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }

    /* Typography */
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }

    /* Grids */
    .recipe-grid {
        grid-template-columns: 1fr;
    }

    .categories-grid {
        grid-template-columns: 1fr;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    :root {
        --container-padding: 0.75rem;
    }

    .hero {
        padding: var(--spacing-2xl) 0;
    }

    section {
        padding: var(--spacing-2xl) 0;
    }
}