/* =================================================================
   THE EXAM HUB - LINKED PAGES STYLES
   Modern, Professional Design System
   ================================================================= */

/* ================================
   CORE STYLES & VARIABLES
   ================================ */
:root {
    /* Color Palette */
    --primary-50: #eff6ff;
    --primary-500: #3b82f6;
    --primary-600: #2563eb;
    --primary-700: #1d4ed8;
    --primary-800: #1e40af;
    
    --secondary-500: #8b5cf6;
    --secondary-600: #7c3aed;
    
    --success-500: #10b981;
    --warning-500: #f59e0b;
    --error-500: #ef4444;
    
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    
    /* Typography */
    --font-primary: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    
    /* 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;
    
    /* Borders */
    --border-radius-sm: 0.375rem;
    --border-radius-md: 0.5rem;
    --border-radius-lg: 0.75rem;
    --border-radius-xl: 1rem;
    --border-radius-2xl: 1.5rem;
    --border-radius-3xl: 2rem;
    
    /* 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), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

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

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

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--gray-800);
    background-color: #ffffff;
    overflow-x: hidden;
}

/* ================================
   TYPOGRAPHY SYSTEM
   ================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: var(--gray-900);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.25rem; }
h3 { font-size: 1.875rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1.125rem; }

p {
    margin-bottom: var(--spacing-md);
    color: var(--gray-700);
}

a {
    color: var(--primary-600);
    text-decoration: none;
    transition: var(--transition-fast);
}

a:hover {
    color: var(--primary-700);
    text-decoration: underline;
}

/* ================================
   CONTAINER & LAYOUT
   ================================ */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-xl);
    }
}

/* ================================
   NAVIGATION SYSTEM
   ================================ */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
    transition: var(--transition-normal);
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
}

.navbar-brand img {
    height: 48px;
    width: auto;
    transition: var(--transition-fast);
}

.navbar-brand img:hover {
    transform: scale(1.05);
}

.navbar-nav {
    display: none;
    gap: var(--spacing-xl);
    list-style: none;
    margin: 0;
    padding: 0;
}

@media (min-width: 768px) {
    .navbar-nav {
        display: flex;
    }
}

.nav-link {
    font-weight: 500;
    color: var(--gray-700);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius-md);
    transition: var(--transition-fast);
}

.nav-link:hover {
    color: var(--primary-600);
    background-color: var(--primary-50);
    text-decoration: none;
}

.mobile-menu-toggle {
    display: block;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--gray-700);
    cursor: pointer;
}

@media (min-width: 768px) {
    .mobile-menu-toggle {
        display: none;
    }
}

/* ================================
   HERO SECTION
   ================================ */
.hero {
    background: linear-gradient(135deg, var(--primary-50) 0%, rgba(139, 92, 246, 0.1) 100%);
    padding: 8rem var(--spacing-md) 4rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero-content {
    position: relative;
    z-index: 10;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-lg);
    background: linear-gradient(135deg, var(--primary-600), var(--secondary-600));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.25rem;
    color: var(--gray-600);
    margin-bottom: var(--spacing-2xl);
}

/* ================================
   BREADCRUMBS
   ================================ */
.breadcrumbs {
    background-color: var(--gray-50);
    padding: var(--spacing-lg) 0;
}

.breadcrumb-nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 0.875rem;
}

.breadcrumb-nav a {
    color: var(--gray-600);
    transition: var(--transition-fast);
}

.breadcrumb-nav a:hover {
    color: var(--primary-600);
    text-decoration: none;
}

.breadcrumb-separator {
    color: var(--gray-400);
}

.breadcrumb-current {
    color: var(--gray-800);
    font-weight: 500;
}

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

.content-wrapper {
    max-width: 800px;
    margin: 0 auto;
}

.content-card {
    background: white;
    border-radius: var(--border-radius-2xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--spacing-xl);
}

.content-title {
    color: var(--gray-900);
    margin-bottom: var(--spacing-lg);
    position: relative;
    padding-bottom: var(--spacing-md);
}

.content-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(135deg, var(--primary-500), var(--secondary-500));
    border-radius: 2px;
}

.content-text {
    line-height: 1.8;
    margin-bottom: var(--spacing-lg);
}

.content-text strong {
    color: var(--gray-900);
    font-weight: 600;
}

/* ================================
   LISTS & TYPOGRAPHY
   ================================ */
.content-list {
    list-style: none;
    padding-left: 0;
    margin-bottom: var(--spacing-lg);
}

.content-list li {
    position: relative;
    padding-left: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.content-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--success-500);
    font-weight: bold;
    width: var(--spacing-md);
    height: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
}

.numbered-list {
    counter-reset: item;
    list-style: none;
    padding-left: 0;
}

.numbered-list li {
    counter-increment: item;
    position: relative;
    padding-left: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
}

.numbered-list li::before {
    content: counter(item);
    position: absolute;
    left: 0;
    top: 0;
    background: var(--primary-500);
    color: white;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
    font-weight: 600;
}

/* ================================
   BUTTONS & ACTIONS
   ================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: var(--transition-fast);
    min-height: 48px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-500), var(--primary-600));
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-600), var(--primary-700));
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    color: white;
    text-decoration: none;
}

/* ================================
   RESPONSIVE DESIGN
   ================================ */
@media (max-width: 767px) {
    .hero {
        padding: 6rem var(--spacing-md) 3rem;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .content-card {
        padding: var(--spacing-lg);
        margin: var(--spacing-md);
    }
    
    h1 { font-size: 2.25rem; }
    h2 { font-size: 1.875rem; }
    h3 { font-size: 1.5rem; }
}

/* ================================
   FOOTER
   ================================ */
.footer {
    background: linear-gradient(135deg, var(--gray-900) 0%, var(--gray-800) 100%);
    color: white;
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

@media (min-width: 768px) {
    .footer-content {
        grid-template-columns: 2fr 1fr 1fr 1fr;
    }
}

.footer-section h3 {
    color: white;
    margin-bottom: var(--spacing-lg);
    font-size: 1.25rem;
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

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

.footer-links a {
    color: var(--gray-300);
    transition: var(--transition-fast);
}

.footer-links a:hover {
    color: white;
    text-decoration: none;
}

.footer-bottom {
    border-top: 1px solid var(--gray-700);
    padding-top: var(--spacing-lg);
    text-align: center;
    color: var(--gray-400);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-top: var(--spacing-md);
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--gray-700);
    color: white;
    border-radius: 50%;
    transition: var(--transition-fast);
}

.social-link:hover {
    background: var(--primary-500);
    transform: translateY(-2px);
    color: white;
    text-decoration: none;
}

/* ================================
   BACK TO TOP BUTTON
   ================================ */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 48px;
    height: 48px;
    background: var(--primary-500);
    color: white;
    border: none;
    border-radius: 50%;
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-normal);
    z-index: 1000;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--primary-600);
    transform: translateY(-2px);
}

/* ================================
   UTILITY CLASSES
   ================================ */
.text-center { text-align: center; }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.text-primary { color: var(--primary-600); }