/* K12 Youth League - Main Stylesheet */
/* Professional and fun design for K12 coding competition platform */

/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    margin-bottom: 1rem;
    color: #2c3e50;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1rem;
    color: #555;
}

a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #2980b9;
}

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

.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -15px;
}

.col {
    flex: 1;
    padding: 0 15px;
}

.col-1 { flex: 0 0 8.333%; }
.col-2 { flex: 0 0 16.666%; }
.col-3 { flex: 0 0 25%; }
.col-4 { flex: 0 0 33.333%; }
.col-6 { flex: 0 0 50%; }
.col-8 { flex: 0 0 66.666%; }
.col-9 { flex: 0 0 75%; }
.col-12 { flex: 0 0 100%; }

/* Header */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 2px 30px rgba(0, 0, 0, 0.15);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: #2c3e50;
    text-decoration: none;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(45deg, #3498db, #9b59b6);
    border-radius: 8px;
    margin-right: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
}

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

.nav-item {
    margin-left: 2rem;
}

.nav-link {
    color: #2c3e50;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    transition: all 0.3s ease;
    position: relative;
}

.nav-link:hover {
    background: linear-gradient(45deg, #3498db, #9b59b6);
    color: white;
    transform: translateY(-2px);
}

.nav-link.active {
    background: linear-gradient(45deg, #e74c3c, #f39c12);
    color: white;
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: 5px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: #2c3e50;
    margin: 3px 0;
    transition: 0.3s;
    border-radius: 2px;
}

/* Main Content */
.main-content {
    margin-top: 80px;
    min-height: calc(100vh - 80px);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.9), rgba(155, 89, 182, 0.9)),
                url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 1000"><polygon fill="%23ffffff10" points="0,0 1000,300 1000,1000 0,700"/><polygon fill="%23ffffff05" points="0,300 1000,100 1000,400 0,600"/></svg>');
    background-size: cover;
    background-position: center;
    padding: 100px 0;
    text-align: center;
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="20" cy="20" r="2" fill="%23ffffff20"/><circle cx="80" cy="40" r="1" fill="%23ffffff30"/><circle cx="40" cy="80" r="1.5" fill="%23ffffff25"/></svg>');
    animation: float 20s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: white;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
    animation: slideInUp 1s ease-out;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: rgba(255, 255, 255, 0.9);
    animation: slideInUp 1s ease-out 0.2s both;
}

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

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border: none;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: linear-gradient(45deg, #e74c3c, #f39c12);
    color: white;
    box-shadow: 0 4px 15px rgba(231, 76, 60, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(231, 76, 60, 0.6);
}

.btn-secondary {
    background: linear-gradient(45deg, #3498db, #9b59b6);
    color: white;
    box-shadow: 0 4px 15px rgba(52, 152, 219, 0.4);
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.6);
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-outline:hover {
    background: white;
    color: #2c3e50;
}

/* Cards */
.card {
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    padding: 2rem;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(45deg, #3498db, #9b59b6);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.card-header {
    border-bottom: 1px solid #eee;
    padding-bottom: 1rem;
    margin-bottom: 1rem;
}

.card-title {
    color: #2c3e50;
    margin-bottom: 0.5rem;
}

.card-subtitle {
    color: #7f8c8d;
    font-size: 0.9rem;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #2c3e50;
}

.form-control {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: white;
}

.form-control:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.form-control.error {
    border-color: #e74c3c;
}

.form-control.success {
    border-color: #27ae60;
}

.form-error {
    color: #e74c3c;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.form-success {
    color: #27ae60;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

/* Tables */
.table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.table th,
.table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #eee;
}

.table th {
    background: linear-gradient(45deg, #3498db, #9b59b6);
    color: white;
    font-weight: 600;
}

.table tr:hover {
    background: #f8f9fa;
}

/* Alerts */
.alert {
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 1rem;
    border-left: 4px solid;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border-left-color: #27ae60;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border-left-color: #e74c3c;
}

.alert-warning {
    background: #fff3cd;
    color: #856404;
    border-left-color: #f39c12;
}

.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    border-left-color: #3498db;
}

/* Badges */
.badge {
    display: inline-block;
    padding: 4px 8px;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-primary { background: #3498db; color: white; }
.badge-success { background: #27ae60; color: white; }
.badge-warning { background: #f39c12; color: white; }
.badge-danger { background: #e74c3c; color: white; }
.badge-info { background: #17a2b8; color: white; }

/* Footer */
.footer {
    background: #2c3e50;
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

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

.footer-section h3 {
    color: white;
    margin-bottom: 1rem;
}

.footer-section p,
.footer-section a {
    color: #bdc3c7;
    margin-bottom: 0.5rem;
}

.footer-section a:hover {
    color: #3498db;
}

.footer-bottom {
    border-top: 1px solid #34495e;
    padding-top: 1rem;
    text-align: center;
    color: #95a5a6;
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.mt-5 { margin-top: 3rem; }

.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 1.5rem; }
.mb-5 { margin-bottom: 3rem; }

.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 1rem; }
.p-4 { padding: 1.5rem; }
.p-5 { padding: 3rem; }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-grid { display: grid; }

/* Responsive Design */
@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 80px);
        background: white;
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: 2rem;
        transition: left 0.3s ease;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-item {
        margin: 1rem 0;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }
    
    .container {
        padding: 0 15px;
    }
    
    .row {
        flex-direction: column;
    }
    
    .col,
    .col-1, .col-2, .col-3, .col-4, .col-6, .col-8, .col-9, .col-12 {
        flex: 0 0 100%;
        margin-bottom: 1rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }
    
    .card {
        padding: 1.5rem;
    }
}

/* Loading Animation */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}

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

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(45deg, #3498db, #9b59b6);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(45deg, #2980b9, #8e44ad);
}