/* GA100 플랫폼 스타일 */
:root {
    --primary: #4f46e5;
    --primary-dark: #4338ca;
    --secondary: #06b6d4;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --dark: #1f2937;
    --light: #f9fafb;
    --border: #e5e7eb;
    --text: #374151;
    --text-light: #6b7280;
}

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

body {
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text);
    background: var(--light);
    line-height: 1.6;
}

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

/* 헤더 */
.header {
    background: white;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo a {
    font-size: 28px;
    font-weight: 800;
    color: var(--dark);
    text-decoration: none;
}

.logo span {
    color: var(--primary);
}

.nav {
    display: flex;
    gap: 30px;
}

.nav a {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.notification-btn {
    position: relative;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 5px;
}

.notification-dot {
    display: none;
    position: absolute;
    top: 5px;
    right: 5px;
    width: 8px;
    height: 8px;
    background: var(--danger);
    border-radius: 50%;
}

.menu-toggle {
    background: var(--primary);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 20px;
    cursor: pointer;
}

/* 사이드바 */
.sidebar {
    position: fixed;
    top: 0;
    right: -350px;
    width: 350px;
    height: 100vh;
    background: white;
    box-shadow: -2px 0 10px rgba(0,0,0,0.1);
    transition: right 0.3s;
    z-index: 1000;
    overflow-y: auto;
}

.sidebar.active {
    right: 0;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid var(--border);
}

.sidebar-header h3 {
    font-size: 24px;
    color: var(--primary);
}

.close-sidebar {
    background: none;
    border: none;
    font-size: 28px;
    cursor: pointer;
    color: var(--text-light);
}

.sidebar-content {
    padding: 20px;
}

.sidebar-section {
    margin-bottom: 30px;
}

.sidebar-section h4 {
    margin-bottom: 15px;
    color: var(--dark);
    font-size: 16px;
}

.sidebar-section a {
    display: block;
    padding: 10px 15px;
    color: var(--text);
    text-decoration: none;
    border-radius: 6px;
    margin-bottom: 5px;
    transition: background 0.3s;
}

.sidebar-section a:hover {
    background: var(--light);
}

.auth-btn {
    width: 100%;
    padding: 12px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s;
}

.auth-btn:hover {
    background: var(--primary-dark);
}

/* 알림 드롭다운 */
.notification-dropdown {
    position: fixed;
    top: 80px;
    right: 20px;
    width: 350px;
    max-height: 500px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    display: none;
    z-index: 1000;
}

.notification-dropdown.active {
    display: block;
}

.notification-header {
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
}

.notification-header h3 {
    font-size: 18px;
}

.notification-list {
    max-height: 400px;
    overflow-y: auto;
}

.notification-item {
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
    transition: background 0.3s;
}

.notification-item:hover {
    background: var(--light);
}

.notification-item.unread {
    background: #eff6ff;
}

.notification-title {
    font-weight: 600;
    margin-bottom: 5px;
}

.notification-time {
    font-size: 12px;
    color: var(--text-light);
}

/* 메인 콘텐츠 */
.main-content {
    min-height: calc(100vh - 70px - 200px);
}

/* 히어로 */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 80px 0;
}

.hero-content {
    text-align: center;
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
}

.hero h1 span {
    color: #fbbf24;
}

.hero p {
    font-size: 20px;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-actions {
    display: flex;
    gap: 15px;
    justify-content: center;
}

/* 버튼 */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    border: 2px solid transparent;
    cursor: pointer;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

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

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

.btn-small {
    padding: 8px 16px;
    font-size: 14px;
}

/* 강의 카드 */
.featured-courses {
    padding: 60px 0;
}

.featured-courses h2 {
    text-align: center;
    font-size: 36px;
    margin-bottom: 40px;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
}

.course-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.course-image {
    position: relative;
    height: 180px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
}

.course-badge {
    position: absolute;
    top: 15px;
    right: 15px;
    background: rgba(255,255,255,0.9);
    color: var(--primary);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.course-content {
    padding: 20px;
}

.course-content h3 {
    font-size: 20px;
    margin-bottom: 10px;
    color: var(--dark);
}

.course-content p {
    color: var(--text-light);
    margin-bottom: 15px;
    font-size: 14px;
}

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

.course-price {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary);
}

/* 통계 */
.stats {
    background: white;
    padding: 60px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.stat-item {
    text-align: center;
    padding: 30px;
}

.stat-number {
    font-size: 48px;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 10px;
}

.stat-label {
    font-size: 18px;
    color: var(--text-light);
}

/* 푸터 */
.footer {
    background: var(--dark);
    color: white;
    padding: 40px 0;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 20px;
}

.footer-links a {
    color: white;
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s;
}

.footer-links a:hover {
    opacity: 1;
}

.footer-info {
    text-align: center;
    opacity: 0.6;
    font-size: 14px;
}

/* 폼 스타일 */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--dark);
}

.form-control {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    transition: border 0.3s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
}

textarea.form-control {
    min-height: 120px;
    resize: vertical;
}

/* 테이블 */
.table {
    width: 100%;
    background: white;
    border-radius: 12px;
    overflow: hidden;
}

.table th {
    background: var(--light);
    padding: 15px;
    text-align: left;
    font-weight: 600;
}

.table td {
    padding: 15px;
    border-top: 1px solid var(--border);
}

/* 뱃지 */
.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}

.badge-success {
    background: #d1fae5;
    color: #065f46;
}

.badge-danger {
    background: #fee2e2;
    color: #991b1b;
}

.badge-warning {
    background: #fef3c7;
    color: #92400e;
}

/* 반응형 */
@media (max-width: 768px) {
    .nav {
        display: none;
    }
    
    .hero h1 {
        font-size: 32px;
    }
    
    .hero p {
        font-size: 16px;
    }
    
    .course-grid {
        grid-template-columns: 1fr;
    }
    
    .sidebar {
        width: 100%;
        right: -100%;
    }
    
    .notification-dropdown {
        right: 10px;
        left: 10px;
        width: auto;
    }
  }