/* 语法专题页面样式 */

.grammar-article {
    padding: 36px 0 60px;
    background: var(--bg-secondary);
    min-height: calc(100vh - 72px);
}

.article-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
    padding: 16px 20px;
    background: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.grammar-level {
    flex-shrink: 0;
    padding: 4px 12px;
    background: linear-gradient(135deg, var(--accent), var(--accent-light));
    color: white;
    border-radius: 16px;
    font-size: 12px;
    font-weight: 600;
}

.article-header h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary);
    margin: 0;
    letter-spacing: -0.3px;
    flex: 1;
}

.article-intro {
    display: none;
}

.grammar-content {
    max-width: 800px;
    margin: 0 auto;
}

.grammar-section {
    background: white;
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.grammar-section h2 {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 12px;
    padding-bottom: 6px;
    border-bottom: 2px solid var(--border);
}

.grammar-section p {
    font-size: 15px;
    line-height: 1.7;
    color: var(--text);
    margin-bottom: 14px;
}

.grammar-box {
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    padding: 16px;
    margin: 16px 0;
    border-left: 4px solid var(--accent);
}

.grammar-box h3 {
    font-size: 16px;
    color: var(--primary);
    margin-bottom: 8px;
}

.grammar-box ul {
    list-style: none;
    padding: 0;
}

.grammar-box li {
    padding: 5px 0;
    font-size: 14px;
    color: var(--text);
}

.grammar-box li strong {
    color: var(--accent);
}

.example-box {
    background: linear-gradient(135deg, #f8f9fa, #e9ecef);
    border-radius: var(--radius-sm);
    padding: 16px;
    margin: 16px 0;
}

.example-box h4 {
    font-size: 16px;
    color: var(--primary);
    margin-bottom: 12px;
}

.example-box ul {
    list-style: none;
    padding: 0;
}

.example-box li {
    padding: 6px 0;
    border-bottom: 1px solid var(--border);
}

.example-box li:last-child {
    border-bottom: none;
}

.de {
    font-weight: 600;
    color: var(--primary);
    font-size: 16px;
}

.zh {
    color: var(--text-light);
    font-size: 14px;
    margin-left: 8px;
}

.grammar-table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    font-size: 15px;
}

.grammar-table th {
    background: var(--primary);
    color: white;
    padding: 14px 16px;
    text-align: left;
    font-weight: 600;
}

.grammar-table td {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border);
    vertical-align: top;
}

.grammar-table tr:nth-child(even) {
    background: var(--bg-secondary);
}

.grammar-table.comparison th {
    background: linear-gradient(135deg, var(--accent), var(--accent-light));
}

.exercise-section {
    background: white;
    border-radius: var(--radius);
    padding: 24px 20px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
}

.exercise-section h2 {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 20px;
    text-align: center;
}

.exercise {
    margin-bottom: 24px;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
}

.exercise h3 {
    font-size: 20px;
    color: var(--primary);
    margin-bottom: 20px;
}

.exercise ol {
    padding-left: 24px;
}

.exercise li {
    padding: 12px 0;
    font-size: 16px;
    line-height: 2;
}

.answer-input {
    padding: 8px 12px;
    border: 2px solid var(--border);
    border-radius: 6px;
    font-size: 15px;
    width: 150px;
    transition: border-color 0.3s;
}

.answer-input:focus {
    outline: none;
    border-color: var(--accent);
}

.answer-input.correct {
    border-color: #10b981;
    background: rgba(16, 185, 129, 0.1);
}

.answer-input.wrong {
    border-color: #ef4444;
    background: rgba(239, 68, 68, 0.1);
}

.check-btn {
    margin-top: 20px;
}

.result {
    margin-top: 16px;
    padding: 16px;
    border-radius: 8px;
    font-weight: 600;
    display: none;
}

.result.show {
    display: block;
}

.result.success {
    background: rgba(16, 185, 129, 0.1);
    color: #10b981;
}

.result.error {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
}

.article-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
}

.nav-link {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: gap 0.3s;
}

.nav-link:hover {
    text-decoration: underline;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .grammar-article {
        padding: 20px 0 40px;
    }

    .article-header {
        padding: 12px 16px;
        margin-bottom: 16px;
        gap: 12px;
    }

    .grammar-level {
        font-size: 11px;
        padding: 3px 10px;
    }

    .article-header h1 {
        font-size: 18px;
        letter-spacing: -0.2px;
    }

    .grammar-section {
        padding: 16px;
        margin-bottom: 16px;
    }

    .grammar-section h2 {
        font-size: 16px;
        margin-bottom: 10px;
        padding-bottom: 6px;
    }

    .grammar-section p {
        font-size: 14px;
        line-height: 1.6;
        margin-bottom: 10px;
    }

    .grammar-table {
        font-size: 13px;
        margin: 16px 0;
    }

    .grammar-table th,
    .grammar-table td {
        padding: 10px 12px;
    }

    .exercise-section {
        padding: 16px;
        margin-bottom: 16px;
    }

    .exercise-section h2 {
        font-size: 18px;
        margin-bottom: 16px;
    }

    .exercise {
        padding: 16px;
        margin-bottom: 16px;
    }

    .exercise h3 {
        font-size: 16px;
        margin-bottom: 12px;
    }

    .exercise li {
        font-size: 14px;
        line-height: 1.8;
    }

    .answer-input {
        width: 120px;
        font-size: 14px;
        padding: 6px 10px;
    }

    .article-nav {
        flex-direction: column;
        gap: 12px;
        margin-top: 16px;
        padding-top: 16px;
        text-align: center;
    }

    .nav-link {
        font-size: 14px;
    }
}