/* 教程列表页面样式 */
.page-title {
    font-size: 36px;
    margin-bottom: 30px;
    text-align: center;
    color: #333;
}

.filter-bar {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 24px;
    background: white;
    border: 2px solid #e0e0e0;
    border-radius: 25px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.filter-btn:hover {
    border-color: #667eea;
    color: #667eea;
}

.filter-btn.active {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-color: transparent;
}

.tutorials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 20px;
}

.tutorial-card {
    background: white;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.3s;
}

.tutorial-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
}

.card-header {
    padding: 20px;
    text-align: center;
}

.card-header .icon {
    width: 60px;
    height: 60px;
    margin: 0 auto;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: bold;
    color: white;
    background: rgba(255, 255, 255, 0.2);
}

.html-bg { background: linear-gradient(135deg, #e44d26, #f16529); }
.css-bg { background: linear-gradient(135deg, #264de4, #2965f1); }
.js-bg { background: linear-gradient(135deg, #f7df1e, #f9dc2e); }
.python-bg { background: linear-gradient(135deg, #3776ab, #ffd43b); }
.java-bg { background: linear-gradient(135deg, #007396, #5382a1); }
.sql-bg { background: linear-gradient(135deg, #00758f, #f29111); }
.git-bg { background: linear-gradient(135deg, #f05032, #de4c36); }
.react-bg { background: linear-gradient(135deg, #61dafb, #21a0c6); }
.ai-bg { background: linear-gradient(135deg, #667eea, #764ba2); }

.card-body {
    padding: 18px;
}

.card-body h3 {
    font-size: 18px;
    margin-bottom: 8px;
    color: #333;
}

.card-body p {
    color: #666;
    margin-bottom: 12px;
    line-height: 1.5;
    font-size: 13px;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    font-size: 14px;
}

.lessons {
    color: #667eea;
    font-weight: 500;
}

.difficulty {
    padding: 3px 10px;
    background: #f0f0f0;
    border-radius: 12px;
    color: #666;
}

.start-btn {
    display: block;
    text-align: center;
    padding: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 5px;
    transition: all 0.3s;
}

.start-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .page-title {
        font-size: 28px;
    }

    .filter-bar {
        gap: 10px;
    }

    .filter-btn {
        padding: 8px 16px;
        font-size: 13px;
    }

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