body {
    margin: 0;
    font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: #f9fafb;
    color: #333;
    line-height: 1.7;
}
header {
    text-align: center;
    padding: 2.5rem 1rem;
    background: linear-gradient(135deg, #4f46e5, #3b82f6);
    color: #fff;
}
header h1 {
    margin: 0;
    font-size: 1.9rem;
    font-weight: 600;
}
header p {
    margin: 0.5rem 0 0;
    font-size: 1.1rem;
    opacity: 0.9;
}
main {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem 3rem;
}
section {
    margin-bottom: 2.5rem;
}
h2 {
    margin-top: 0;
    font-size: 1.5rem;
    color: #1f2937;
    border-bottom: 1px solid #e5e7eb;
    padding-bottom: 0.5rem;
}
h3 {
    font-size: 1.2rem;
    color: #374151;
    margin: 1.2rem 0 0.8rem;
}
p, ul, ol {
    margin: 0.8rem 0;
    color: #374151;
}
.note {
    background: #e0f2fe;
    border-left: 4px solid #3b82f6;
    padding: 1rem;
    border-radius: 6px;
    margin: 1.2rem 0;
    color: #1e3a8a;
}
.warning {
    background: #fef3c7;
    border-left: 4px solid #f59e0b;
    padding: 1rem;
    border-radius: 6px;
    margin: 1.2rem 0;
    color: #92400e;
}
.success {
    background: #dcfce7;
    border-left: 4px solid #22c55e;
    padding: 1rem;
    border-radius: 6px;
    margin: 1.2rem 0;
    color: #166534;
}
code {
    background: #f3f4f6;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: monospace;
    font-size: 0.95rem;
}
.btn, .btn:hover {
    display: inline-block;
    margin: 0.8rem 0;
    padding: 0.6rem 1.2rem;
    color: #fff;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
}
.btn {
    background: #1d4ed8;
}
.btn:hover {
    background: #1e40af;
}
.btn-danger, .btn-danger:hover {
    background: #dc2626;
}
.btn-danger:hover {
    background: #b91c1c;
}
footer {
    text-align: center;
    font-size: 0.9rem;
    color: #6b7280;
    padding: 1.5rem 0;
    border-top: 1px solid #e5e7eb;
    background: #f3f4f6;
}
a {
    color: #2563eb;
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}
.security-section {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.security-section h2 {
    font-size: 1.4rem;
    color: #1f2937;
    border-bottom: 1px solid #d1d5db;
    padding-bottom: 0.5rem;
}

.security-section ul {
    color: #374151;
    margin: 1rem 0;
    padding-left: 1.2rem;
}

.back-to-top {
    text-align: right;
    margin-top: 1.5rem;
    font-size: 0.9rem;
    color: #6b7280;
}

.back-to-top a {
    color: #3b82f6;
}
code {
    background: #f3f4f6;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: monospace;
    font-size: 0.95rem;
}

pre {
    background: #f3f4f6;
    padding: 1rem;
    border-radius: 6px;
    overflow-x: auto;
    margin: 0.8rem 0;
}