/* 全局样式 - 高对比度版 */
:root {
    --primary: #818cf8;
    --primary-light: #a5b4fc;
    --success: #4ade80;
    --warning: #facc15;
    --danger: #f87171;
    --bg-dark: #000000;
    --bg-card: #1a1a2e;
    --bg-input: #2a2a3e;
    --text-primary: #ffffff;
    --text-secondary: #e0e0e0;
    --border-color: #555577;
}

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

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-color: #000000;
    color: #ffffff;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-weight: 400;
}

main {
    flex: 1;
    padding-bottom: 2rem;
}

/* 卡片样式 */
.card {
    border: 2px solid #555577;
    background: #1a1a2e;
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.5);
    color: #ffffff;
}

.card-header {
    background: #2a2a3e;
    border-bottom: 2px solid #555577;
    font-weight: 600;
    border-radius: 16px 16px 0 0 !important;
    color: #ffffff;
    padding: 16px;
}

.card-body {
    color: #ffffff;
    padding: 20px;
}

.card-body p,
.card-body small,
.card-body span {
    color: #ffffff;
    font-weight: 400;
}

.card-body small.text-muted {
    color: #cccccc !important;
}

/* 按钮样式 */
.btn {
    border-radius: 12px;
    font-weight: 700;
    transition: all 0.2s;
    border: none;
    font-size: 1rem;
}

.btn:active {
    transform: scale(0.95);
}

.btn-lg {
    padding: 14px 28px;
    font-size: 1.1rem;
}

/* 组选择按钮 */
.group-btn {
    padding: 14px;
    border-radius: 12px;
    border: 2px solid #555577;
    background: #2a2a3e;
    color: #ffffff;
    font-weight: 700;
    transition: all 0.2s;
    font-size: 1rem;
}

.group-btn:hover {
    border-color: var(--primary);
    background: #3a3a4e;
}

.group-btn.active {
    border-color: var(--primary);
    background: var(--primary);
    color: #000000;
}

/* 统计数字 */
.stat-value {
    font-size: 2rem;
    font-weight: 800;
    color: #ffffff;
}

.stat-label {
    font-size: 0.9rem;
    color: #cccccc;
    font-weight: 600;
}

/* 排行榜 */
.leaderboard-item {
    display: flex;
    align-items: center;
    padding: 14px;
    border-bottom: 1px solid #333355;
    background: transparent;
}

.leaderboard-item:hover {
    background: rgba(255,255,255,0.08);
}

.leaderboard-item .fw-bold {
    color: #ffffff;
    font-size: 1rem;
}

.leaderboard-item small {
    color: #cccccc;
}

.leaderboard-rank {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    margin-right: 12px;
    font-size: 1.1rem;
}

.rank-1 { background: linear-gradient(135deg, #fbbf24, #f59e0b); color: #000; }
.rank-2 { background: linear-gradient(135deg, #d1d5db, #9ca3af); color: #000; }
.rank-3 { background: linear-gradient(135deg, #d97706, #b45309); color: #fff; }
.rank-other { background: #2a2a3e; color: #ffffff; }

/* 签到卡片 */
.checkin-card {
    background: linear-gradient(135deg, #2a2a1e, #2a1a1e);
    border: 2px solid #886600;
}

.checkin-btn {
    background: linear-gradient(135deg, #eab308, #ef4444);
    border: none;
    color: #000000;
    font-weight: 800;
    padding: 18px 36px;
    border-radius: 16px;
    font-size: 1.2rem;
    transition: all 0.3s;
}

.checkin-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(234, 179, 8, 0.5);
}

/* 学习卡片样式 */
.word-display {
    background: linear-gradient(135deg, #2a2a4e, #1a1a3e);
    border: 2px solid #6366f1;
    border-radius: 16px;
    padding: 24px;
    margin-bottom: 24px;
}

.meaning-text {
    font-size: 1.6rem;
    font-weight: 800;
    color: #ffffff;
    line-height: 1.4;
}

.phonetic-text {
    font-size: 1.1rem;
    color: #cccccc;
    margin-top: 8px;
}

.pos-badge {
    display: inline-block;
    background: #6366f1;
    color: #ffffff;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.9rem;
    margin-top: 8px;
    font-weight: 700;
}

/* 选项按钮 */
.option-btn {
    padding: 16px;
    font-size: 1.05rem;
    text-align: left;
    border: 2px solid #555577;
    background: #2a2a3e;
    color: #ffffff;
    transition: all 0.2s;
    min-height: 60px;
    display: flex;
    align-items: center;
    font-weight: 500;
}

.option-btn:hover {
    border-color: var(--primary);
    background: #3a3a4e;
}

.option-btn.correct {
    border-color: var(--success);
    background: rgba(74, 222, 128, 0.3);
    color: #ffffff;
    font-weight: 600;
}

.option-btn.wrong {
    border-color: var(--danger);
    background: rgba(248, 113, 113, 0.3);
    color: #ffffff;
    font-weight: 600;
}

.option-btn.disabled {
    opacity: 0.8;
    cursor: not-allowed;
}

/* 进度条 */
.progress {
    height: 10px;
    border-radius: 5px;
    background: #2a2a3e;
    overflow: hidden;
}

.progress-bar {
    border-radius: 5px;
    transition: width 0.3s ease;
}

/* 输入框 */
.form-control {
    background: #2a2a3e;
    border: 2px solid #555577;
    color: #ffffff;
    border-radius: 12px;
    padding: 16px;
    font-size: 1.1rem;
}

.form-control:focus {
    background: #2a2a3e;
    border-color: var(--primary);
    color: #ffffff;
    box-shadow: 0 0 0 3px rgba(129, 140, 248, 0.5);
}

.form-control::placeholder {
    color: #999999;
}

/* 反馈提示 */
.feedback {
    padding: 18px;
    border-radius: 12px;
    margin-top: 16px;
    font-weight: 500;
    font-size: 1.1rem;
}

.feedback-correct {
    background: rgba(74, 222, 128, 0.3);
    border: 2px solid var(--success);
    color: #ffffff;
}

.feedback-wrong {
    background: rgba(248, 113, 113, 0.3);
    border: 2px solid var(--danger);
    color: #ffffff;
}

/* 下一步按钮 */
.next-btn {
    background: linear-gradient(135deg, #6366f1, #818cf8);
    border: none;
    color: #ffffff;
    font-weight: 800;
    padding: 18px 48px;
    border-radius: 16px;
    font-size: 1.2rem;
    transition: all 0.3s;
}

.next-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.6);
    color: #ffffff;
}

/* 标签 */
.badge {
    padding: 8px 14px;
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.9rem;
}

.badge-review {
    background: rgba(248, 113, 113, 0.4);
    color: #ffffff;
    border: 2px solid var(--danger);
}

.badge.bg-primary {
    background: #6366f1 !important;
    color: #ffffff;
}

.badge.bg-light {
    background: #ffffff !important;
    color: #000000;
}

/* 导航栏 */
.navbar {
    background: #000000 !important;
    border-bottom: 2px solid #333355;
    padding: 12px 0;
}

.navbar-brand {
    font-weight: 800;
    font-size: 1.3rem;
    color: #ffffff !important;
}

.nav-link {
    color: #cccccc !important;
    font-weight: 600;
}

.nav-link:hover {
    color: #ffffff !important;
}

/* 页脚 */
footer {
    background: #0a0a1a;
    border-top: 2px solid #333355;
    padding: 20px 0;
    margin-top: auto;
}

footer small {
    color: #999999;
}

/* 提示文字 */
.text-muted {
    color: #cccccc !important;
}

/* 表格 */
.table {
    color: #ffffff;
}

.table th {
    background: #2a2a3e;
    color: #ffffff;
    font-weight: 700;
}

.table td {
    border-color: #333355;
    color: #ffffff;
}

/* 警告框 */
.alert-warning {
    background: rgba(234, 179, 8, 0.2);
    border: 2px solid #eab308;
    color: #ffffff;
}

/* 响应式布局 */
@media (max-width: 768px) {
    .container {
        padding: 0 12px;
    }
    
    .card {
        border-radius: 12px;
        margin-bottom: 12px;
    }
    
    .card-body {
        padding: 16px;
    }
    
    .meaning-text {
        font-size: 1.3rem;
    }
    
    .option-btn {
        padding: 14px;
        font-size: 0.95rem;
    }
    
    .btn-lg {
        padding: 14px 20px;
        font-size: 1rem;
    }
    
    .stat-value {
        font-size: 1.8rem;
    }
    
    .group-btn {
        padding: 12px;
        font-size: 0.9rem;
    }
    
    .word-display {
        padding: 18px;
    }
    
    .form-control {
        padding: 14px;
        font-size: 1rem;
    }
    
    .next-btn {
        padding: 16px 32px;
        font-size: 1.1rem;
    }
    
    .checkin-btn {
        padding: 16px 28px;
        font-size: 1.1rem;
    }
}

@media (max-width: 480px) {
    .col-3 {
        flex: 0 0 50%;
        max-width: 50%;
    }
    
    .option-btn {
        padding: 12px;
        font-size: 0.9rem;
    }
    
    .meaning-text {
        font-size: 1.2rem;
    }
    
    .stat-value {
        font-size: 1.5rem;
    }
}