/* ========== 基础重置 ========== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh; padding: 20px; color: #333;
}

.container {
    max-width: 1100px; margin: 0 auto;
}

/* ========== 头部 ========== */
header {
    text-align: center; padding: 30px 20px 20px;
}
header h1 { font-size: 2em; color: #fff; margin-bottom: 6px; }
.subtitle { color: rgba(255,255,255,0.75); font-size: 0.95em; }

.main-header {
    display: flex; justify-content: space-between; align-items: center;
    padding: 20px; background: #fff; border-radius: 12px 12px 0 0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
.main-header h1 { font-size: 1.4em; color: #333; margin-bottom: 0; }
.main-header .subtitle { color: #999; margin-top: 2px; }

/* ========== 登录/注册卡片 ========== */
.login-card {
    background: #fff; border-radius: 12px; padding: 36px 30px;
    max-width: 420px; margin: 0 auto;
    box-shadow: 0 8px 32px rgba(0,0,0,0.12);
}
.login-card h2 { font-size: 1.3em; margin-bottom: 18px; color: #333; }
.hint { color: #999; font-size: 0.85em; margin-bottom: 14px; }
.hint.small { font-size: 0.8em; text-align: center; }
.hint a { color: #667eea; text-decoration: none; }

/* ========== 表单 ========== */
.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-size: 0.85em; color: #666; margin-bottom: 4px; font-weight: 500; }
.form-group input, .form-group select {
    width: 100%; padding: 10px 12px; border: 1.5px solid #e0e0e0;
    border-radius: 8px; font-size: 0.95em; transition: border-color 0.2s;
}
.form-group input:focus {
    outline: none; border-color: #667eea; box-shadow: 0 0 0 3px rgba(102,126,234,0.15);
}
.form-row { display: flex; gap: 12px; }
.form-row .form-group { flex: 1; }

/* ========== 按钮 ========== */
.btn {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 10px 20px; border: none; border-radius: 8px; font-size: 0.93em;
    cursor: pointer; transition: all 0.2s; text-decoration: none;
}
.btn-primary { background: #667eea; color: #fff; }
.btn-primary:hover { background: #5a6fd6; }
.btn-outline { background: #fff; color: #667eea; border: 1.5px solid #667eea; }
.btn-outline:hover { background: #f0f2ff; }
.btn-danger { background: #e74c3c; color: #fff; padding: 5px 12px; font-size: 0.82em; }
.btn-danger:hover { background: #c0392b; }
.btn-edit { background: #2ecc71; color: #fff; padding: 5px 12px; font-size: 0.82em; margin-right: 6px; }
.btn-edit:hover { background: #27ae60; }
.btn-sm { padding: 6px 14px; font-size: 0.82em; }
.btn-block { display: block; width: 100%; }

/* ========== 工具栏 ========== */
.toolbar {
    background: #fff; padding: 14px 20px; display: flex; gap: 10px;
    border-top: 1px solid #f0f0f0; align-items: center;
}
.toolbar input {
    flex: 1; padding: 9px 12px; border: 1.5px solid #e0e0e0; border-radius: 8px;
    font-size: 0.93em;
}
.toolbar input:focus { outline: none; border-color: #667eea; }

/* ========== 表格 ========== */
.table-wrap {
    background: #fff; padding: 0 20px 20px; overflow-x: auto;
}
table { width: 100%; border-collapse: collapse; font-size: 0.93em; }
thead th {
    text-align: left; padding: 12px 10px; border-bottom: 2px solid #667eea;
    color: #667eea; font-weight: 600; white-space: nowrap;
}
tbody td {
    padding: 12px 10px; border-bottom: 1px solid #f0f0f0;
}
tbody tr:hover { background: #f8f9ff; }
.loading, .empty { text-align: center; color: #999; padding: 40px 0 !important; }

/* ========== 成绩徽章 ========== */
.badge {
    display: inline-block; padding: 3px 10px; border-radius: 12px;
    font-size: 0.82em; font-weight: 600; color: #fff;
}
.badge-excellent { background: #2ecc71; }
.badge-good { background: #3498db; }
.badge-normal { background: #f39c12; }
.badge-poor { background: #e74c3c; }

/* ========== 统计卡片 ========== */
.stats {
    background: #fff; padding: 16px 20px; border-radius: 0 0 12px 12px;
    display: flex; gap: 14px; border-top: 1px solid #f0f0f0;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
.stat-card {
    flex: 1; text-align: center; padding: 14px 10px; border-radius: 8px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}
.stat-value { display: block; font-size: 1.6em; font-weight: 700; color: #fff; }
.stat-label { display: block; font-size: 0.78em; color: rgba(255,255,255,0.8); margin-top: 4px; }

/* ========== 错误消息 ========== */
.error-msg { color: #e74c3c; font-size: 0.85em; margin-bottom: 10px; min-height: 1.2em; }
.error-bar {
    background: #fff3cd; color: #856404; padding: 10px 20px; border-left: 4px solid #ffc107;
    font-size: 0.88em;
}

/* ========== 弹窗 ========== */
.modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.45); display: flex; justify-content: center;
    align-items: center; z-index: 1000; opacity: 0; pointer-events: none;
    transition: opacity 0.25s;
}
.modal-overlay.show { opacity: 1; pointer-events: auto; }
.modal {
    background: #fff; border-radius: 12px; padding: 28px 30px; width: 90%; max-width: 480px;
    box-shadow: 0 16px 48px rgba(0,0,0,0.2);
}
.modal h2 { margin-bottom: 18px; font-size: 1.2em; }
.modal-actions { display: flex; gap: 10px; justify-content: flex-end; margin-top: 20px; }

/* ========== 响应式 ========== */
@media (max-width: 600px) {
    body { padding: 10px; }
    .login-card { padding: 24px 18px; }
    .form-row { flex-direction: column; gap: 0; }
    .main-header { flex-direction: column; gap: 10px; }
    .toolbar { flex-wrap: wrap; }
    .stats { flex-direction: column; }
}