/* CSS 변수 */
:root {
    --primary-color: #4f46e5;
    --primary-dark: #4338ca;
    --secondary-color: #10b981;
    --secondary-dark: #059669;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;
    --success-color: #10b981;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --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);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Noto Sans KR', sans-serif;
    color: var(--text-primary);
    background-color: var(--bg-light);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

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

/* 헤더 */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 1rem 0;
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 700;
}

.logo i {
    font-size: 1.8rem;
}

.header-title {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.1rem;
    font-weight: 500;
}

/* 메인 컨텐츠 */
.main-content {
    flex: 1;
    padding: 2rem 0;
}

/* 환영 섹션 */
.welcome-section {
    text-align: center;
    padding: 3rem 0;
}

.welcome-section h1 {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

/* 역할 카드 */
.role-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 3rem 0;
}

.role-card {
    background: var(--bg-white);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    transition: all 0.3s ease;
    cursor: pointer;
    border: 3px solid transparent;
}

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

.teacher-card {
    border-color: var(--primary-color);
}

.teacher-card:hover {
    border-color: var(--primary-dark);
}

.student-card {
    border-color: var(--secondary-color);
}

.student-card:hover {
    border-color: var(--secondary-dark);
}

.role-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2.5rem;
}

.teacher-card .role-icon {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
}

.student-card .role-icon {
    background: linear-gradient(135deg, var(--secondary-color), var(--secondary-dark));
    color: white;
}

.role-card h2 {
    text-align: center;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.role-card > p {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.feature-list {
    list-style: none;
    margin: 1.5rem 0;
}

.feature-list li {
    padding: 0.5rem 0;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.feature-list i {
    color: var(--success-color);
}

/* 버튼 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    font-family: 'Noto Sans KR', sans-serif;
}

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

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

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

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

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

.role-card .btn {
    width: 100%;
    justify-content: center;
    margin-top: 1rem;
}

/* 특징 섹션 */
.features-section {
    padding: 3rem 0;
}

.features-section h2 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

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

.feature-item {
    text-align: center;
    padding: 2rem;
    background: var(--bg-white);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
}

.feature-item i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.feature-item h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

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

/* 탭 메뉴 */
.tab-menu {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
    flex-wrap: wrap;
}

.tab-btn {
    background: none;
    border: none;
    padding: 1rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: 'Noto Sans KR', sans-serif;
}

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

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* 섹션 헤더 */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.section-header h2 {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-primary);
}

/* 폼 카드 */
.form-card {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    margin-bottom: 2rem;
}

.form-card h3 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: 'Noto Sans KR', sans-serif;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

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

.form-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    flex-wrap: wrap;
}

/* 학생 목록 */
.students-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.student-card-item {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
}

.student-card-item:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-3px);
}

.student-card-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
}

.student-card-header h3 {
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.student-info-grid {
    display: grid;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.student-info-item {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
}

.student-info-item i {
    width: 20px;
    color: var(--primary-color);
}

.student-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-icon {
    padding: 0.5rem;
    border-radius: 6px;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.btn-delete:hover {
    background: #dc2626;
}

/* 수업 내역 */
.lessons-history {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.lesson-card {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--primary-color);
}

.lesson-header {
    display: flex;
    justify-content: space-between;
    align-items: start;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.lesson-title {
    flex: 1;
}

.lesson-title h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.lesson-meta {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.lesson-meta span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.lesson-badges {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.badge-progress {
    background: #dbeafe;
    color: #1e40af;
}

.badge-attitude {
    background: #dcfce7;
    color: #166534;
}

.lesson-content {
    margin: 1rem 0;
    padding: 1rem;
    background: var(--bg-light);
    border-radius: 8px;
}

.lesson-content h4 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.lesson-content p {
    color: var(--text-secondary);
    line-height: 1.8;
    white-space: pre-line;
}

.lesson-homework {
    margin-top: 1rem;
    padding: 1rem;
    background: #fef3c7;
    border-radius: 8px;
    border-left: 4px solid var(--warning-color);
}

.lesson-homework h4 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.lesson-notes {
    margin-top: 1rem;
    padding: 1rem;
    background: #e0e7ff;
    border-radius: 8px;
}

.lesson-notes h4 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.lesson-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* 필터 그룹 */
.filter-group,
.sort-group {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.filter-select {
    padding: 0.5rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: 'Noto Sans KR', sans-serif;
    font-size: 0.9rem;
}

/* 학생 선택 섹션 */
.student-select-section {
    margin-bottom: 2rem;
}

.large-select {
    padding: 1rem;
    font-size: 1.1rem;
}

/* 정보 카드 */
.info-card {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow-md);
    margin-bottom: 2rem;
}

.info-header {
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.info-header h3 {
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.info-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.info-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
}

.info-value {
    font-size: 1.1rem;
    color: var(--text-primary);
    font-weight: 700;
}

/* 통계 카드 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: white;
}

.stat-icon.blue {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
}

.stat-icon.green {
    background: linear-gradient(135deg, #10b981, #059669);
}

.stat-icon.orange {
    background: linear-gradient(135deg, #f59e0b, #d97706);
}

.stat-info {
    flex: 1;
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* 수업 목록 */
.lessons-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* 로딩 */
.loading {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
}

/* 빈 상태 */
.empty-state {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 4rem;
    margin-bottom: 1rem;
    color: var(--border-color);
}

/* 푸터 */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 1.5rem 0;
    margin-top: 3rem;
    text-align: center;
}

/* 반응형 */
@media (max-width: 768px) {
    .welcome-section h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .role-cards {
        grid-template-columns: 1fr;
    }

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

    .tab-menu {
        flex-direction: column;
    }

    .tab-btn {
        width: 100%;
        justify-content: center;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }

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

    .students-list {
        grid-template-columns: 1fr;
    }

    .lesson-header {
        flex-direction: column;
    }

    .lesson-badges {
        width: 100%;
    }

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

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