:root { font: 100%/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif; color: #1d1d1f; background: #f5f5f7; font-optical-sizing: auto; }
* { box-sizing: border-box; }
body { margin: 0; }
a { color: #0066cc; text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible { outline: 3px solid #0071e3; outline-offset: 5px; }
.skip { position: absolute; left: 16px; top: -80px; z-index: 3; background: white; padding: 10px; }
.skip:focus { top: 10px; }
header { position: sticky; top: 0; z-index: 2; background: rgba(255,255,255,.9); backdrop-filter: blur(20px) saturate(150%); }
nav { max-width: 1100px; margin: auto; padding: 18px 28px; display: flex; align-items: center; gap: 28px; font-size: .85rem; }
.brand { color: #1d1d1f; font-weight: 650; font-size: 1rem; }
nav > span { color: #616166; }
.back { margin-left: auto; }
main { max-width: 1100px; margin: auto; padding: 0 28px; }
.hero { text-align: center; padding: 88px 0 80px; }
.eyebrow { color: #626268; font-size: .85rem; font-weight: 600; letter-spacing: .04em; margin: 0 0 16px; }
h1 { font-size: clamp(2.4rem, 5.6vw, 4.5rem); line-height: 1.12; letter-spacing: -.035em; margin: 0 0 28px; font-weight: 700; }
.intro { color: #626268; font-size: clamp(1rem, 2vw, 1.3rem); margin: 0 0 24px; line-height: 1.8; }
.text-link { font-size: 1rem; }
h2 { font-size: clamp(1.8rem, 3.6vw, 2.8rem); line-height: 1.2; letter-spacing: -.025em; margin: 0 0 24px; font-weight: 650; }
h3 { font-size: 1.15rem; line-height: 1.4; margin: 0 0 12px; }
p { margin: 0 0 20px; }
.flow { background: #fff; border-radius: 28px; padding: 40px; }
.steps { list-style: none; padding: 0; margin: 36px 0 0; display: grid; grid-template-columns: repeat(4,1fr); gap: 30px; }
.number { display: block; font-size: 1.9rem; font-weight: 600; color: #0071e3; margin-bottom: 24px; letter-spacing: -.03em; }
.steps p { font-size: .9rem; color: #626268; margin: 0; }
.session { scroll-margin-top: 100px; display: grid; grid-template-columns: 1.1fr 1fr; gap: 54px; align-items: center; padding: 96px 0; }
.session-copy > p:not(.eyebrow) { color: #626268; }
strong { color: #1d1d1f; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.button { display: inline-flex; align-items: center; gap: 10px; min-height: 44px; padding: 11px 20px; border: 1px solid #0071e3; border-radius: 999px; background: #0071e3; color: white; font-size: .9rem; line-height: 1.5; }
.button:hover { background: #0077ed; text-decoration: none; }
.button:active { transform: scale(.98); }
.secondary { background: transparent; color: #0066cc; }
.secondary:hover { background: #e8f1fb; }
.caption { font-size: .75rem; margin: 16px 0 0; }
.copy-card { background: white; padding: 34px; border-radius: 26px; }
.copy-card > p { color: #626268; font-size: .9rem; }
.shortcut { border-top: 1px solid #e7e7eb; padding: 20px 0; }
.shortcut > span { display: block; font-size: .8rem; font-weight: 600; margin-bottom: 12px; }
.shortcut > div { display: flex; align-items: center; gap: 7px; font-size: .8rem; flex-wrap: wrap; }
kbd { font: inherit; min-width: 30px; text-align: center; padding: 5px 9px; background: #f5f5f7; border: 1px solid #dddde2; border-radius: 7px; box-shadow: 0 2px 0 #dddde2; }
.then { padding: 0 4px; color: #626268; }
.copy-card .mobile-tip { margin: 0; padding-top: 16px; border-top: 1px solid #e7e7eb; font-size: .8rem; }
.example { display: grid; grid-template-columns: 1fr 1.1fr; gap: 50px; align-items: center; }
.example p:not(.eyebrow) { color: #626268; }
.code-window { min-width: 0; background: #1d1d1f; border-radius: 22px; overflow: hidden; color: #e4e4e9; }
.code-caption { padding: 16px 22px; display: flex; flex-wrap: wrap; gap: 8px; justify-content: space-between; border-bottom: 1px solid #3e3e43; font-size: .7rem; color: #bdbdc5; }
pre { margin: 0; padding: 26px; overflow: auto; font: .85rem/1.8 ui-monospace, "SFMono-Regular", Consolas, monospace; }
.privacy { display: flex; gap: 16px; padding: 26px 30px; margin: 44px 0 0; border: 1px solid #dedee4; border-radius: 18px; }
.privacy > span { color: #626268; font-size: 1.3rem; }
.privacy h3 { font-size: .95rem; margin-bottom: 5px; }
.privacy p { font-size: .85rem; color: #626268; margin: 0; }
.start { text-align: center; padding: 88px 0; }
.start p { color: #626268; }
.start .actions { justify-content: center; }
footer { max-width: 1100px; padding: 24px 28px; margin: auto; border-top: 1px solid #dedee4; display: flex; justify-content: space-between; font-size: .75rem; color: #626268; }
@media (max-width: 800px) { .steps { grid-template-columns: 1fr 1fr; gap: 32px; } .session, .example { grid-template-columns: 1fr; gap: 28px; } .session { padding: 64px 0; } }
@media (max-width: 480px) { nav { gap: 12px; padding: 16px 20px; flex-wrap: wrap; } nav > span { font-size: .75rem; } main { padding: 0 20px; } .hero { padding: 60px 0; } .flow { padding: 28px; } .steps { grid-template-columns: 1fr; gap: 26px; } .number { margin-bottom: 8px; } .copy-card { padding: 26px; } .privacy { padding: 22px; } .start { padding: 64px 0; } }
@media (prefers-reduced-motion: reduce) { .button:active { transform: none; } }
@media (prefers-reduced-transparency: reduce), (prefers-contrast: more) { header { background: #fff; backdrop-filter: none; } }