.shipping-main { --muted: #aaa; --soft: #111; --button-bg: #fff; --button-text: #000; }
:root:not([data-theme="dark"]) .shipping-main { --muted: #606060; --soft: #f7f7f8; --button-bg: #202020; --button-text: #fff; }
html { scroll-behavior: smooth; }
.shipping-main { font-family: "Douyin Sans", Arial, "Microsoft YaHei", "PingFang SC", sans-serif; }
.shipping-main h1, .shipping-main h2, .shipping-main h3, .shipping-main p { margin: 0; }
.shipping-main p, .shipping-main h1, .shipping-main h2, .shipping-main h3 { transition: color 420ms ease; }
.page-width { width: min(960px, 64%); margin-inline: auto; }
.shipping-hero { position: relative; isolation: isolate; overflow: hidden; text-align: center; padding: 44px 24px 48px; }
.shipping-hero-art { position: absolute; inset: 0 0 auto; width: 100%; height: 100%; object-fit: cover; z-index: -1; opacity: .45; filter: invert(1) hue-rotate(180deg); mix-blend-mode: screen; transition: opacity 420ms ease, filter 420ms ease; }
:root:not([data-theme="dark"]) .shipping-hero-art { opacity: 1; filter: none; mix-blend-mode: normal; }
.eyebrow { font-size: 12px; font-weight: 600; letter-spacing: .08em; }
.shipping-hero h1 { margin-top: 28px; font-size: clamp(36px, 4vw, 58px); line-height: 1.15; font-weight: 700; letter-spacing: -.035em; }
.shipping-hero .hero-description { margin-top: 14px; color: var(--muted); font-size: 15px; line-height: 1.8; }
.page-actions { display: flex; justify-content: center; flex-wrap: wrap; gap: 12px; margin-top: 24px; }
.pill { display: inline-flex; min-height: 38px; padding: 9px 19px; align-items: center; justify-content: center; border: 1px solid transparent; border-radius: 999px; text-decoration: none; font-size: 12px; font-weight: 600; line-height: 1.5; transition: background-color 420ms ease, color 420ms ease, border-color 420ms ease, transform 200ms ease; }
.pill-solid { background: var(--button-bg); color: var(--button-text); }
.pill-outline { border-color: var(--rule); color: var(--foreground); }
.pill:hover { transform: translateY(-2px); }
.pill-outline:hover { border-color: currentColor; }
.shipping-main a:focus-visible, .shipping-main summary:focus-visible { outline: 2px solid currentColor; outline-offset: 5px; }
.feature-list { padding-top: 18px; padding-bottom: 40px; scroll-margin-top: 30px; }
.feature-row { display: grid; grid-template-columns: 1.55fr 1fr; gap: 30px; align-items: start; margin-bottom: 64px; }
.feature-image { display: block; width: 100%; height: auto; aspect-ratio: 1.75; object-fit: cover; border-radius: 3px; }
.feature-copy { padding-top: 2px; }
.feature-copy .section-number { color: var(--muted); font-size: 10px; letter-spacing: .04em; margin-bottom: 12px; }
.feature-copy h2 { font-size: clamp(20px, 2.05vw, 29px); line-height: 1.4; font-weight: 650; letter-spacing: -.035em; }
.feature-copy > p:not(.section-number) { margin-top: 16px; font-size: 13px; line-height: 1.85; color: var(--muted); }
.feature-copy > .feature-note { font-size: 11px !important; margin-top: 14px !important; }
.practical-section { padding: 52px 0 60px; background: var(--soft); transition: background-color 420ms ease; }
.section-heading { text-align: center; margin-bottom: 32px; }
.section-heading h2 { font-size: clamp(24px, 2.6vw, 36px); line-height: 1.4; font-weight: 650; letter-spacing: -.03em; }
.section-heading > p { margin-top: 10px; color: var(--muted); font-size: 13px; line-height: 1.8; }
.practical-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; }
.practical-card img { display: block; width: 100%; height: auto; aspect-ratio: 1.75; object-fit: cover; border-radius: 3px; }
.practical-card h3 { font-size: 19px; line-height: 1.5; margin-top: 20px; font-weight: 600; }
.practical-card > p { color: var(--muted); font-size: 13px; line-height: 1.9; margin-top: 8px; }
.text-link { display: inline-block; margin-top: 16px; font-size: 12px; text-underline-offset: 4px; }
.before-start { padding-block: 62px 72px; scroll-margin-top: 24px; }
.faq-list { max-width: 720px; margin: auto; }
.faq-list details { border-bottom: 1px solid var(--rule); scroll-margin-top: 30px; }
.faq-list summary { padding: 21px 8px 21px 0; font-size: 14px; line-height: 1.6; cursor: pointer; }
.faq-list details > p { font-size: 13px; line-height: 1.9; color: var(--muted); padding: 0 22px 20px 0; }
.faq-list .download-link { color: var(--foreground); text-underline-offset: 4px; }
.shipping-footer { background: #000; color: #fff; text-align: center; padding: 54px 24px 28px; }
.shipping-footer .footer-wordmark { font-size: 12px; letter-spacing: .1em; margin-bottom: 21px; color: #aaa; }
.shipping-footer h2 { font-size: 24px; line-height: 1.5; }
.shipping-footer > p:not(.footer-wordmark):not(.footer-credit) { font-size: 13px; line-height: 1.8; margin-top: 12px; color: #aaa; }
.shipping-footer .pill { border-color: #444; color: #fff; margin-top: 24px; }
.shipping-footer .footer-credit { font-size: 10px; color: #888; margin-top: 38px; }
.shipping-main [data-reveal] { opacity: 1; transform: none; }
.shipping-main.motion-ready [data-reveal]:not(.is-visible) { opacity: 0; transform: translateY(16px); }
.shipping-main [data-reveal] { transition: opacity 650ms ease, transform 650ms cubic-bezier(.22, 1, .36, 1); }
@media (max-width: 900px) {
  .page-width { width: calc(100% - 64px); max-width: 760px; }
  .feature-row { gap: 24px; }
}
@media (max-width: 600px) {
  .page-width { width: calc(100% - 40px); }
  .shipping-hero { padding: 48px 20px 60px; }
  .shipping-hero h1 { margin-top: 28px; font-size: 40px; }
  .shipping-hero .hero-description { font-size: 14px; }
  .pill { min-height: 44px; }
  .feature-list { padding-top: 0; padding-bottom: 30px; }
  .feature-row { grid-template-columns: 1fr; gap: 24px; margin-bottom: 48px; }
  .feature-copy h2 { font-size: 25px; }
  .feature-copy > p:not(.section-number) { font-size: 14px; margin-top: 12px; }
  .feature-copy > .feature-note { font-size: 12px !important; }
  .practical-section { padding-block: 40px 44px; }
  .practical-grid { grid-template-columns: 1fr; gap: 36px; }
  .section-heading > p { font-size: 13px; }
  .before-start { padding-block: 44px 52px; }
  .faq-list summary { min-height: 60px; }
}
/* A screen per chapter on computers and landscape tablets; phones keep the compact flow. */
@media (min-width: 1200px) and (min-height: 500px), (min-width: 768px) and (min-height: 500px) and (orientation: landscape) {
  .shipping-hero {
    min-height: calc(100svh - var(--header-height));
    display: grid;
    place-items: center;
    padding: 48px 32px;
  }
  .shipping-hero h1 { font-size: clamp(58px, 6vw, 88px); }
  .shipping-hero .hero-description { font-size: clamp(15px, 1.3vw, 18px); margin-top: 24px; }
  .page-actions { margin-top: 32px; }
  .feature-list { width: 100%; max-width: none; padding: 0; scroll-margin-top: 0; }
  .feature-row {
    min-height: calc(100svh - var(--header-height));
    margin: 0;
    padding: 64px max(40px, calc((100vw - 1200px) / 2));
    grid-template-columns: 1.35fr 1fr;
    gap: clamp(32px, 5vw, 88px);
    align-items: center;
  }
  .feature-copy h2 { font-size: clamp(28px, 3vw, 43px); }
  .feature-copy > p:not(.section-number) { font-size: clamp(14px, 1.15vw, 17px); margin-top: 24px; }
  .feature-copy .section-number { font-size: 12px; margin-bottom: 18px; }
  .feature-copy > .feature-note { font-size: 12px !important; margin-top: 20px !important; }
  .practical-section { min-height: calc(100svh - var(--header-height)); display: grid; align-items: center; padding-block: 64px; }
  .practical-section > .page-width { width: min(1100px, calc(100% - 80px)); max-width: none; }
  .practical-grid { gap: 40px; }
  .practical-card h3 { font-size: clamp(19px, 1.65vw, 24px); }
  .practical-card > p { font-size: 14px; }
  .before-start { min-height: calc(100svh - var(--header-height)); display: flex; flex-direction: column; justify-content: center; }
  .before-start .faq-list { width: 100%; margin: 0 auto; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .shipping-main [data-reveal], .shipping-main p, .shipping-main h1, .shipping-main h2, .shipping-main h3, .shipping-hero-art, .practical-section, .pill { transition: none; }
  .shipping-main.motion-ready [data-reveal]:not(.is-visible) { opacity: 1; transform: none; }
}