:root {
    --red: #f2473f;
    --red-dark: #d9342d;
    --ink: #202127;
    --muted: #707480;
    --line: #e9e9ee;
    --paper: #fff;
    --green: #23ad7a;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    color: var(--ink);
    background:
        radial-gradient(circle at 90% 4%, rgba(255, 222, 205, .45), transparent 27rem),
        #f7f8fc;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

.seo-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: min(1080px, calc(100% - 40px));
    margin: 0 auto;
    padding: 24px 0;
}

.seo-brand { display: inline-flex; align-items: center; gap: 10px; }
.seo-brand > span {
    display: grid;
    place-items: center;
    width: 42px;
    height: 42px;
    color: #fff;
    background: var(--red);
    border-radius: 13px;
    box-shadow: 0 9px 20px rgba(242, 71, 63, .2);
    font-size: 20px;
    font-weight: 900;
}
.seo-brand strong { font-size: 18px; }
.seo-header-action {
    padding: 10px 16px;
    color: #fff;
    background: var(--ink);
    border-radius: 10px;
    font-size: 13px;
    font-weight: 750;
}

.seo-shell {
    width: min(960px, calc(100% - 40px));
    margin: 12px auto 60px;
}

.seo-breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 0 0 14px 8px;
    color: #8b8e98;
    font-size: 12px;
}
.seo-breadcrumb a:hover { color: var(--red); }

.seo-article {
    padding: clamp(28px, 6vw, 64px);
    background: var(--paper);
    border: 1px solid rgba(231, 231, 237, .9);
    border-radius: 28px;
    box-shadow: 0 24px 70px rgba(31, 35, 48, .07);
}

.seo-article-header {
    padding-bottom: 30px;
    border-bottom: 1px solid var(--line);
}
.seo-article-header > span {
    display: inline-block;
    padding: 6px 10px;
    color: var(--red-dark);
    background: #fff0ee;
    border-radius: 8px;
    font-size: 12px;
    font-weight: 800;
}
.seo-article-header h1 {
    max-width: 760px;
    margin: 18px 0 16px;
    font-size: clamp(31px, 5vw, 50px);
    line-height: 1.16;
    letter-spacing: -.04em;
}
.seo-article-header p {
    max-width: 760px;
    margin: 0;
    color: var(--muted);
    font-size: 16px;
    line-height: 1.9;
}

.seo-section { padding-top: 34px; }
.seo-section h2 {
    margin: 0 0 14px;
    font-size: 24px;
    line-height: 1.4;
}
.seo-section h3 { margin: 24px 0 9px; font-size: 18px; }
.seo-section p, .seo-section li {
    color: #555964;
    font-size: 15px;
    line-height: 1.9;
}
.seo-section p { margin: 10px 0; }
.seo-section ol, .seo-section ul { margin: 12px 0 0; padding-left: 23px; }
.seo-section li + li { margin-top: 8px; }
.seo-section strong { color: var(--ink); }

.seo-note {
    margin-top: 22px;
    padding: 17px 19px;
    color: #5a5140;
    background: #fff9e9;
    border: 1px solid #f4dfaa;
    border-radius: 14px;
    font-size: 14px;
    line-height: 1.8;
}

.seo-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-top: 18px;
}
.seo-steps > div {
    padding: 18px;
    background: #f8f8fb;
    border: 1px solid var(--line);
    border-radius: 15px;
}
.seo-steps b {
    display: grid;
    place-items: center;
    width: 28px;
    height: 28px;
    margin-bottom: 12px;
    color: #fff;
    background: var(--red);
    border-radius: 50%;
    font-size: 13px;
}
.seo-steps strong, .seo-steps span { display: block; }
.seo-steps strong { margin-bottom: 6px; font-size: 15px; }
.seo-steps span { color: var(--muted); font-size: 13px; line-height: 1.7; }

.seo-guide-image {
    margin: 22px 0 0;
    overflow: hidden;
    border: 1px solid var(--line);
    border-radius: 17px;
}
.seo-guide-image img { display: block; width: 100%; height: auto; }
.seo-guide-image figcaption {
    padding: 10px 14px;
    color: var(--muted);
    background: #fafafd;
    font-size: 12px;
    text-align: center;
}

.seo-faq { margin-top: 16px; border-top: 1px solid var(--line); }
.seo-faq details { padding: 16px 2px; border-bottom: 1px solid var(--line); }
.seo-faq summary { font-weight: 750; cursor: pointer; }
.seo-faq p { margin-bottom: 0; }

.seo-cta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    margin-top: 42px;
    padding: 24px;
    color: #fff;
    background: linear-gradient(135deg, #25262e, #17181e);
    border-radius: 20px;
}
.seo-cta small, .seo-cta strong, .seo-cta p { display: block; }
.seo-cta small { margin-bottom: 5px; color: #ffb9b5; font-weight: 750; }
.seo-cta strong { font-size: 18px; line-height: 1.5; }
.seo-cta p { max-width: 590px; margin: 7px 0 0; color: #afb1bb; font-size: 12px; line-height: 1.7; }
.seo-cta > a {
    flex: 0 0 auto;
    padding: 13px 17px;
    color: #fff;
    background: var(--red);
    border-radius: 11px;
    font-size: 14px;
    font-weight: 800;
}

.seo-related { margin-top: 22px; }
.seo-related h2 { margin: 0 0 12px 4px; font-size: 17px; }
.seo-related > div { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.seo-related a {
    padding: 17px;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 14px;
}
.seo-related a[aria-current="page"] { border-color: #f2b8b4; box-shadow: inset 3px 0 var(--red); }
.seo-related strong, .seo-related span { display: block; }
.seo-related strong { margin-bottom: 5px; font-size: 14px; }
.seo-related span { color: var(--muted); font-size: 12px; line-height: 1.6; }

.seo-footer {
    padding: 0 20px 34px;
    color: #999ca6;
    font-size: 12px;
    text-align: center;
}

@media (max-width: 680px) {
    .seo-header { width: calc(100% - 28px); padding: 16px 0; }
    .seo-brand > span { width: 37px; height: 37px; border-radius: 11px; font-size: 18px; }
    .seo-brand strong { font-size: 16px; }
    .seo-header-action { padding: 9px 12px; font-size: 12px; }
    .seo-shell { width: calc(100% - 24px); margin-top: 5px; }
    .seo-article { padding: 24px 19px; border-radius: 21px; }
    .seo-article-header h1 { font-size: 32px; }
    .seo-article-header p { font-size: 15px; line-height: 1.8; }
    .seo-section { padding-top: 28px; }
    .seo-section h2 { font-size: 21px; }
    .seo-steps { grid-template-columns: 1fr; }
    .seo-cta { align-items: stretch; flex-direction: column; }
    .seo-cta > a { text-align: center; }
    .seo-related > div { grid-template-columns: 1fr; }
}