* { box-sizing: border-box; }

body {
    font-family: -apple-system, "Segoe UI", "Microsoft YaHei", sans-serif;
    max-width: 760px;
    margin: 0 auto;
    padding: 32px 20px;
    background-color: #f5f7fa;
    color: #1a1a1a;
}

h1 {
    text-align: center;
    font-size: 32px;
    margin-bottom: 8px;
    border-bottom: 2px solid #e0e0e0;
    padding-bottom: 12px;
}

.A1 {
    text-align: center;
    color: #666;
    margin-bottom: 28px;
}

.A5 {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.A6 {
    display: flex;
    align-items: center;
    gap: 16px;
    background: #fff;
    border: 1px solid #e3e6ea;
    border-radius: 10px;
    padding: 16px 20px;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.06);
    transition: box-shadow 0.2s, border-color 0.2s;
}

.A6:hover {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border-color: #ccc;
}

.A7 {
    width: 56px;
    height: 48px;
    flex-shrink: 0;
}

.A8 {
    flex: 1;
    min-width: 0;
}

.A8 h2 {
    margin: 0 0 4px;
    font-size: 20px;
}

.A9 {
    margin: 0 0 4px;
    color: #666;
    font-size: 14px;
}

.A10 {
    margin: 0;
    color: #999;
    font-size: 13px;
}

.A11 {
    background: #c74634;
    color: #fff;
    text-decoration: none;
    padding: 10px 26px;
    border-radius: 6px;
    font-weight: bold;
    white-space: nowrap;
    flex-shrink: 0;
    transition: background 0.2s;
}

.A11:hover {
    background: #a83626;
}

.A12 {
    margin-top: 20px;
    color: #666;
    font-size: 14px;
}

.A12 a {
    color: #1a73e8;
    text-decoration: none;
}

.A14 {
    margin-top: 8px;
}

.A14 a {
    color: #1a73e8;
    text-decoration: none;
}

/* ===== OS 切换标签 ===== */
.A2 {
    display: flex;
    gap: 4px;
    border-bottom: 1px solid #e0e0e0;
    margin-bottom: 20px;
}

.A3 {
    padding: 10px 22px;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 15px;
    color: #666;
    border-bottom: 2px solid transparent;
    margin-bottom: -1px;
    border-radius: 8px 8px 0 0;
    transition: background 0.2s, color 0.2s, box-shadow 0.2s;
}

.A3:hover {
    color: #333;
    background: #eef1f5;
}

.A3.active {
    color: #c74634;
    border-bottom-color: #c74634;
    font-weight: bold;
    background: #fff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
}

.A4.hidden {
    display: none;
}

.A13 {
    text-align: center;
    color: #999;
    padding: 50px 0;
    font-size: 15px;
}

.A15 {
    text-align: center;
    color: #999;
    font-size: 13px;
    margin-top: 24px;
    padding-top: 12px;
    border-top: 1px solid #e0e0e0;
}

/* ===== 架构分组 ===== */
.A16 {
    margin-top: 20px;
}

.A17 {
    margin: 0 0 10px;
    font-size: 18px;
    color: #333;
}

.A18 {
    margin: 0;
    color: #999;
    font-size: 14px;
}

.A19 {
    font-size: 13px;
    color: #999;
    font-weight: normal;
}