/* ============================================================================
   PRASHANTEDU - CBSE Exam Papers Website
   Color Scheme: Emerald Green + Gold Accent
   ============================================================================ */

:root {
    --primary: #10B981;
    --primary-dark: #059669;
    --primary-light: #D1FAE5;
    --accent: #F59E0B;
    --accent-dark: #D97706;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-white: #ffffff;
    --bg-light: #F0FDF4;
    --border-color: #e5e7eb;
    --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);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

a {
    text-decoration: none;
    color: inherit;
}

/* ============================================================================
   NAVIGATION
   ============================================================================ */

#navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: var(--bg-white);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: var(--transition);
}

#navbar.scrolled {
    box-shadow: var(--shadow-md);
}

#navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-dark);
}

.nav-brand span {
    color: var(--accent);
}

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

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover {
    color: var(--primary-dark);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary);
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    transition: var(--transition);
}

/* ============================================================================
   HERO SECTION
   ============================================================================ */

.hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(135deg, var(--bg-light) 0%, #ECFDF5 100%);
    min-height: 80vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-text h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.hero-text h1 span {
    color: var(--primary);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.8;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-features {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    padding: 2rem;
    background: var(--bg-white);
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.hero-feature {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    border-radius: 0.5rem;
    background: var(--bg-light);
}

.hero-feature-icon {
    width: 48px;
    height: 48px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
}

.hero-feature-text h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.hero-feature-text p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* ============================================================================
   BUTTONS
   ============================================================================ */

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    border-radius: 0.5rem;
    font-weight: 600;
    font-size: 1rem;
    transition: var(--transition);
    border: 2px solid transparent;
    cursor: pointer;
}

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

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

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

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

.btn-accent {
    background-color: var(--accent);
    color: white;
    border-color: var(--accent);
}

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

/* ============================================================================
   SECTIONS
   ============================================================================ */

section {
    padding: 5rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ============================================================================
   CLASS CARDS (Homepage)
   ============================================================================ */

.classes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.class-card {
    background: var(--bg-white);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    border: 2px solid transparent;
}

.class-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.class-card-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.class-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-light);
    border-radius: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-dark);
}

.class-card h3 {
    font-size: 1.5rem;
    font-weight: 700;
}

.class-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.class-subjects {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.subject-tag {
    padding: 0.375rem 0.75rem;
    background: var(--bg-light);
    border-radius: 2rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.subject-tag.highlight {
    background: var(--primary-light);
    color: var(--primary-dark);
    font-weight: 500;
}

/* ============================================================================
   PAPER CARDS (Subject pages)
   ============================================================================ */

.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.paper-card {
    background: var(--bg-white);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.paper-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.paper-preview {
    height: 200px;
    background: linear-gradient(135deg, var(--bg-light) 0%, #E5E7EB 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.paper-preview img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.paper-preview-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
}

.paper-preview-placeholder svg {
    width: 48px;
    height: 48px;
    opacity: 0.5;
}

.paper-badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    padding: 0.375rem 0.75rem;
    background: var(--accent);
    color: white;
    border-radius: 2rem;
    font-size: 0.75rem;
    font-weight: 600;
}

.paper-content {
    padding: 1.5rem;
}

.paper-content h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.paper-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.paper-meta span {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.paper-description {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    margin-bottom: 1.5rem;
}

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

.paper-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-dark);
}

.paper-price span {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 400;
}

/* ============================================================================
   BREADCRUMB
   ============================================================================ */

.breadcrumb {
    padding: 1rem 0;
    margin-top: 4rem;
}

.breadcrumb-list {
    display: flex;
    list-style: none;
    gap: 0.5rem;
    font-size: 0.875rem;
}

.breadcrumb-list li {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.breadcrumb-list li:not(:last-child)::after {
    content: '/';
    color: var(--text-secondary);
}

.breadcrumb-list a {
    color: var(--text-secondary);
    transition: var(--transition);
}

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

.breadcrumb-list li:last-child {
    color: var(--text-primary);
    font-weight: 500;
}

/* ============================================================================
   PAGE HEADER
   ============================================================================ */

.page-header {
    padding: 2rem 0 3rem;
    background: var(--bg-light);
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.page-header p {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* ============================================================================
   FEATURES SECTION
   ============================================================================ */

.features {
    background: var(--bg-light);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    text-align: center;
    padding: 2rem;
}

.feature-icon {
    width: 64px;
    height: 64px;
    background: var(--primary);
    border-radius: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: white;
    font-size: 1.5rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.feature-card p {
    color: var(--text-secondary);
}

/* ============================================================================
   YOUTUBE SECTION
   ============================================================================ */

.youtube-section {
    background: var(--bg-white);
}

.youtube-embed {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    max-width: 800px;
    margin: 0 auto;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.youtube-embed iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* ============================================================================
   FOOTER
   ============================================================================ */

footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1.5rem;
}

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

.footer-brand h3 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.footer-brand h3 span {
    color: var(--accent);
}

.footer-brand p {
    color: #9CA3AF;
    font-size: 0.9375rem;
}

.footer-links h4 {
    font-size: 1rem;
    margin-bottom: 1rem;
}

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

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #9CA3AF;
    transition: var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 1.5rem;
    text-align: center;
    color: #9CA3AF;
    font-size: 0.875rem;
}

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

@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-white);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow-lg);
        padding: 2rem 0;
        gap: 1rem;
    }

    .nav-menu.active {
        left: 0;
    }

    .hero {
        padding: 6rem 0 3rem;
        min-height: auto;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-text h1 {
        font-size: 2rem;
    }

    .hero-cta {
        justify-content: center;
    }

    .hero-features {
        order: -1;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .page-header h1 {
        font-size: 1.75rem;
    }

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

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .btn {
        padding: 0.75rem 1.25rem;
        font-size: 0.9375rem;
    }

    .hero-text h1 {
        font-size: 1.75rem;
    }

    .class-card {
        padding: 1.5rem;
    }
}