/* ===== 全局重置与基础 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.8;
    color: #333;
    background-color: #f5f7fa;
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

/* ===== 容器 ===== */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem 2.5rem;
    background-color: #fff;
    box-shadow: 0 0 30px rgba(0,0,0,0.08);
    min-height: 100vh;
    overflow-x: hidden;
}

/* ===== 标题 ===== */
.header {
    text-align: center;
    padding: 3rem 1rem 2rem;
    border-bottom: 3px solid #1e40af;
    margin-bottom: 2rem;
}

.header h1 {
    font-size: 2rem;
    color: #1e40af;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.subtitle {
    font-size: 1rem;
    color: #ea580c;
    font-weight: 500;
}

h2 {
    font-size: 1.5rem;
    color: #1e40af;
    margin: 2.5rem 0 1rem;
    padding-left: 0.8rem;
    border-left: 5px solid #ea580c;
    line-height: 1.4;
}

h3 {
    font-size: 1.2rem;
    color: #1e40af;
    margin: 2rem 0 0.8rem;
    line-height: 1.4;
}

h4 {
    font-size: 1.05rem;
    color: #333;
    margin: 1.5rem 0 0.6rem;
    font-weight: 600;
}

/* ===== 段落与列表 ===== */
p {
    margin-bottom: 1rem;
    line-height: 1.9;
}

ul, ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0.4rem;
    line-height: 1.8;
}

/* ===== 图片 - 响应式自适应 ===== */
.content-img {
    display: block;
    max-width: 100%;
    height: auto;
    margin: 1.5rem auto;
    border-radius: 8px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.12);
}

.img-center {
    margin-left: auto;
    margin-right: auto;
}

/* 尺寸class：只设 max-width，不强制 width:100%，让图片按原始比例自然显示 */
.img-sm { max-width: 280px; }
.img-md { max-width: 420px; }
.img-lg { max-width: 600px; }
.img-xl { max-width: 800px; }
.img-full { max-width: 100%; }

.img-caption {
    text-align: center;
    font-size: 0.85rem;
    color: #888;
    margin-top: -0.8rem;
    margin-bottom: 1.5rem;
    font-style: italic;
}

/* ===== 表格 ===== */
.table-wrapper {
    overflow-x: auto;
    margin: 1.5rem 0;
    -webkit-overflow-scrolling: touch;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.92rem;
    min-width: 600px;
}

th {
    background-color: #1e40af;
    color: #fff;
    padding: 0.7rem 0.8rem;
    text-align: left;
    white-space: nowrap;
}

td {
    padding: 0.6rem 0.8rem;
    border-bottom: 1px solid #e5e7eb;
    vertical-align: top;
}

tr:nth-child(even) td {
    background-color: #f8fafc;
}

tr:hover td {
    background-color: #f0f4ff;
}

/* ===== 提示框 ===== */
.tip-box {
    background-color: #eff6ff;
    border-left: 4px solid #1e40af;
    padding: 1rem 1.2rem;
    margin: 1.5rem 0;
    border-radius: 0 6px 6px 0;
}

.warning-box {
    background-color: #fff7ed;
    border-left: 4px solid #ea580c;
    padding: 1rem 1.2rem;
    margin: 1.5rem 0;
    border-radius: 0 6px 6px 0;
}

.danger-box {
    background-color: #fef2f2;
    border-left: 4px solid #dc2626;
    padding: 1rem 1.2rem;
    margin: 1.5rem 0;
    border-radius: 0 6px 6px 0;
}

.success-box {
    background-color: #f0fdf4;
    border-left: 4px solid #16a34a;
    padding: 1rem 1.2rem;
    margin: 1.5rem 0;
    border-radius: 0 6px 6px 0;
}

.info-box {
    background-color: #f5f3ff;
    border-left: 4px solid #7c3aed;
    padding: 1rem 1.2rem;
    margin: 1.5rem 0;
    border-radius: 0 6px 6px 0;
}

.note-box {
    background-color: #f8fafc;
    border: 1px solid #e2e8f0;
    padding: 1rem 1.2rem;
    margin: 1.5rem 0;
    border-radius: 6px;
    font-size: 0.9rem;
    color: #555;
}

/* ===== 目录 ===== */
.toc {
    background-color: #f8fafc;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    padding: 1.5rem 2rem;
    margin: 2rem 0;
}

.toc h3 {
    margin-top: 0;
    color: #1e40af;
}

.toc ul {
    list-style: none;
    padding-left: 0;
}

.toc > ul > li {
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.toc ul ul {
    padding-left: 1.5rem;
    margin-top: 0.3rem;
    font-weight: 400;
}

.toc a {
    color: #1e40af;
    text-decoration: none;
}

.toc a:hover {
    color: #ea580c;
    text-decoration: underline;
}

/* ===== 分割线 ===== */
hr {
    border: none;
    border-top: 2px solid #e5e7eb;
    margin: 3rem 0;
}

/* ===== 链接 ===== */
a {
    color: #1e40af;
}

a:hover {
    color: #ea580c;
}

/* ===== 响应式布局 - 移动端适配 ===== */
@media (max-width: 768px) {
    body { font-size: 15px; }
    .container { padding: 1rem 1.2rem; }
    .header h1 { font-size: 1.5rem; }
    .subtitle { font-size: 0.9rem; }
    h2 { font-size: 1.25rem; margin: 2rem 0 0.8rem; }
    h3 { font-size: 1.1rem; }
    h4 { font-size: 1rem; }

    /* 移动端图片降级：限制最大高度防止首屏被占满 */
    .img-sm { max-width: 200px; }
    .img-md { max-width: 85%; }
    .img-lg, .img-xl, .img-full {
        max-width: 100%;
        max-height: 250px;
        object-fit: cover;
    }
    .content-img {
        margin: 1rem auto;
        border-radius: 4px;
    }

    /* 移动端目录紧凑化 */
    .toc { padding: 1rem 1.2rem; margin: 1.5rem 0; }
    .toc ul ul { padding-left: 1rem; }
    .table-wrapper { margin: 1rem -0.2rem; }
    table { font-size: 0.82rem; }
    th, td { padding: 0.5rem 0.6rem; }
    .tip-box, .warning-box, .danger-box, .success-box, .info-box, .note-box {
        padding: 0.8rem 1rem; margin: 1rem 0;
    }
}

@media (max-width: 480px) {
    body { font-size: 14px; }
    .container { padding: 0.8rem 1rem; }
    .header h1 { font-size: 1.3rem; }
    .img-sm { max-width: 150px; }
    .img-md { max-width: 100%; }
    .img-lg, .img-xl, .img-full { max-height: 180px; }
}