* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: #303642;
    background: #f5f7fa;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.75;
}

a {
    color: #1677ff;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.content-nav {
    position: sticky;
    top: 0;
    z-index: 20;
    border-bottom: 1px solid #e8ebef;
    background: rgba(255, 255, 255, .96);
    backdrop-filter: blur(10px);
}

.content-nav-inner {
    width: min(1120px, calc(100% - 32px));
    min-height: 60px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.content-brand {
    color: #202631;
    font-size: 18px;
    font-weight: 700;
    white-space: nowrap;
}

.content-nav-links {
    display: flex;
    align-items: center;
    gap: 22px;
    font-size: 14px;
}

.content-nav-links a {
    color: #505866;
}

.content-shell {
    width: min(920px, calc(100% - 32px));
    margin: 0 auto;
    padding: 28px 0 56px;
}

.breadcrumbs {
    margin-bottom: 18px;
    color: #7a8493;
    font-size: 13px;
}

.breadcrumbs span {
    margin: 0 8px;
    color: #b2b8c1;
}

.content-article {
    overflow: hidden;
    border: 1px solid #e7eaee;
    border-radius: 18px;
    background: #fff;
    box-shadow: 0 8px 30px rgba(31, 35, 48, .06);
}

.article-header {
    padding: 44px 52px 34px;
    border-bottom: 1px solid #edf0f3;
    background: linear-gradient(145deg, #f7fbff, #fff);
}

.article-kicker {
    display: inline-block;
    margin-bottom: 12px;
    color: #1677ff;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: .08em;
}

.article-header h1 {
    margin: 0;
    color: #202631;
    font-size: clamp(30px, 5vw, 44px);
    line-height: 1.25;
}

.article-summary {
    max-width: 760px;
    margin: 18px 0 0;
    color: #56606f;
    font-size: 17px;
}

.article-meta {
    margin-top: 18px;
    color: #8a929e;
    font-size: 13px;
}

.article-body {
    padding: 38px 52px 52px;
}

.article-body h2 {
    margin: 42px 0 16px;
    padding-top: 6px;
    color: #202631;
    font-size: 25px;
    line-height: 1.4;
}

.article-body h2:first-child {
    margin-top: 0;
}

.article-body h3 {
    margin: 24px 0 8px;
    color: #303642;
    font-size: 18px;
}

.article-body p {
    margin: 0 0 16px;
}

.article-body ul,
.article-body ol {
    margin: 10px 0 20px;
    padding-left: 24px;
}

.article-body li + li {
    margin-top: 7px;
}

.key-takeaway,
.formula-card,
.risk-box,
.editor-box {
    margin: 22px 0;
    padding: 18px 20px;
    border-radius: 12px;
}

.key-takeaway {
    border-left: 4px solid #1677ff;
    background: #f0f7ff;
}

.formula-card {
    border: 1px solid #dbeafe;
    background: #f8fbff;
}

.formula {
    margin: 12px 0;
    padding: 14px;
    border-radius: 8px;
    color: #144b8b;
    background: #eaf4ff;
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    text-align: center;
}

.risk-box {
    border: 1px solid #ffe0a3;
    background: #fff9eb;
    color: #76520b;
}

.editor-box {
    border: 1px solid #e5e8ec;
    background: #fafbfc;
    color: #596271;
}

.definition-grid,
.process-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
    margin: 20px 0;
}

.definition-card,
.process-card {
    padding: 18px;
    border: 1px solid #e8ebef;
    border-radius: 12px;
    background: #fafbfd;
}

.definition-card h3,
.process-card h3 {
    margin-top: 0;
}

.definition-card p,
.process-card p {
    margin-bottom: 0;
    color: #626c7a;
    font-size: 14px;
}

.process-number {
    display: inline-grid;
    width: 28px;
    height: 28px;
    margin-bottom: 10px;
    place-items: center;
    border-radius: 50%;
    color: #fff;
    background: #1677ff;
    font-size: 13px;
    font-weight: 700;
}

.content-table-wrap {
    overflow-x: auto;
    margin: 20px 0 26px;
    border: 1px solid #e7eaee;
    border-radius: 12px;
}

.content-table {
    width: 100%;
    min-width: 650px;
    border-collapse: collapse;
    font-size: 14px;
}

.content-table th,
.content-table td {
    padding: 13px 15px;
    border-bottom: 1px solid #edf0f3;
    text-align: left;
    vertical-align: top;
}

.content-table th {
    color: #343b47;
    background: #f6f8fa;
}

.content-table tr:last-child td {
    border-bottom: 0;
}

.faq-list {
    margin-top: 16px;
}

.faq-list details {
    padding: 16px 18px;
    border: 1px solid #e7eaee;
    border-radius: 10px;
    background: #fff;
}

.faq-list details + details {
    margin-top: 10px;
}

.faq-list summary {
    color: #303642;
    cursor: pointer;
    font-weight: 650;
}

.faq-list details p {
    margin: 12px 0 0;
    color: #626c7a;
}

.content-footer {
    border-top: 1px solid #e3e7eb;
    background: #fff;
}

.content-footer-inner {
    width: min(920px, calc(100% - 32px));
    margin: 0 auto;
    padding: 28px 0 34px;
    color: #7a8493;
    font-size: 13px;
}

.content-footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-bottom: 10px;
}

.content-footer-links a {
    color: #56606f;
}

@media (max-width: 700px) {
    .content-nav-inner {
        min-height: 54px;
    }

    .content-nav-links a:nth-child(n+4) {
        display: none;
    }

    .content-nav-links {
        gap: 14px;
    }

    .content-shell {
        width: min(100% - 20px, 920px);
        padding-top: 16px;
    }

    .article-header,
    .article-body {
        padding: 26px 20px;
    }

    .article-summary {
        font-size: 15px;
    }

    .article-body h2 {
        font-size: 22px;
    }

    .definition-grid,
    .process-grid {
        grid-template-columns: 1fr;
    }
}