:root {
  color-scheme: light;
  --brand: #4fa8aa;
  --brand-deep: #3d8f91;
  --brand-light: #f0f9fa;
  --border: #b8e0e3;
  --ink: #0e2e30;
  --muted: #3a6668;
  --serif: "Noto Serif SC", "Songti SC", "STSong", serif;
  --body: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { background: #fff; min-width: 280px; }
body { margin: 0; color: var(--ink); font-family: var(--body); -webkit-font-smoothing: antialiased; }
button, input { font: inherit; }
button { cursor: pointer; touch-action: manipulation; }
button:disabled { cursor: default; }
.site-header, .auth-layout, .site-footer { width: min(1040px, calc(100% - 96px)); margin-inline: auto; }
.site-header { display: flex; align-items: center; justify-content: space-between; padding-top: max(36px, env(safe-area-inset-top)); }
.wordmark { display: inline-flex; align-items: baseline; gap: 12px; }
.wordmark-cn { font-family: var(--serif); font-size: 27px; font-weight: 600; letter-spacing: .09em; }
.wordmark-en { color: var(--brand-deep); font-size: 11px; font-weight: 650; letter-spacing: .16em; }
.header-caption { font-size: 12px; color: var(--muted); letter-spacing: .1em; }
.auth-layout { min-height: calc(100svh - 162px); display: grid; grid-template-columns: 1fr 400px; align-items: center; column-gap: 112px; padding-block: 64px; }
.auth-story { position: relative; padding-left: 28px; }
.story-rule { width: 2px; height: 38px; background: var(--brand); position: absolute; top: 0; left: 0; }
.eyebrow { margin: 0 0 26px; color: var(--muted); font-size: 10px; letter-spacing: .18em; }
.auth-story h2 { font-family: var(--serif); font-weight: 500; font-size: clamp(46px, 4.8vw, 62px); line-height: 1.48; letter-spacing: .04em; margin: 0 0 25px; }
.story-copy { color: var(--muted); font-size: 14px; line-height: 2; margin: 0; }
.notebook-lines { width: 180px; display: grid; gap: 12px; margin-top: 40px; }
.notebook-lines i { display: block; height: 1px; background: var(--border); }
.notebook-lines i:nth-child(2) { width: 82%; }
.notebook-lines i:nth-child(3) { width: 57%; }
.auth-panel { min-width: 0; border: 1px solid var(--border); padding: 36px 32px 28px; background: #fff; border-radius: 6px; box-shadow: 0 10px 36px #0e2e3005; }
.panel-label { color: var(--brand-deep); display: flex; align-items: center; gap: 7px; font-size: 11px; letter-spacing: .06em; margin: 0 0 22px; }
.private-dot { width: 5px; height: 5px; border-radius: 50%; background: var(--brand); }
h1 { font-family: var(--serif); font-weight: 600; font-size: 25px; line-height: 1.5; letter-spacing: .025em; margin: 0 0 9px; }
.auth-description { color: var(--muted); font-size: 13px; line-height: 1.85; min-height: 24px; margin: 0 0 28px; }
.field { margin-bottom: 20px; }
.field label { display: block; font-size: 13px; font-weight: 550; margin-bottom: 9px; }
.field input { display: block; width: 100%; min-width: 0; min-height: 48px; padding: 11px 13px; border: 1px solid var(--border); border-radius: 4px; color: var(--ink); background: #fff; outline: none; font-size: 16px; line-height: 1.5; transition: border-color .15s, box-shadow .15s; }
.field input:focus { border-color: var(--brand-deep); box-shadow: 0 0 0 3px var(--brand-light); }
.field input[aria-invalid="true"] { border-color: var(--brand-deep); box-shadow: inset 3px 0 var(--brand-deep); }
.field input:disabled { opacity: .7; background: #fafcfc; }
.field-hint { margin: 8px 0 0; color: var(--muted); font-size: 11px; line-height: 1.7; }
.primary-button { display: flex; align-items: center; justify-content: center; gap: 13px; width: 100%; min-height: 48px; border: 1px solid var(--brand-deep); border-radius: 4px; background: var(--brand-deep); color: #fff; font-size: 14px; font-weight: 550; padding: 11px 14px; transition: opacity .15s, background .15s; }
.primary-button svg { width: 18px; height: 18px; }
.primary-button:hover:not(:disabled) { background: var(--ink); border-color: var(--ink); }
.primary-button:focus-visible, .retry-button:focus-visible { outline: 2px solid var(--brand-deep); outline-offset: 4px; }
.primary-button:disabled { opacity: .55; }
form[aria-busy="true"] .primary-button svg { display: none; }
.feedback { color: var(--muted); font-size: 12px; line-height: 1.85; min-height: 23px; margin-top: 16px; overflow-wrap: anywhere; }
.feedback.is-error { color: var(--ink); border-left: 2px solid var(--brand-deep); padding-left: 10px; }
.retry-button { border: 0; border-bottom: 1px solid var(--border); background: transparent; color: var(--brand-deep); font-size: 13px; min-height: 44px; padding: 7px 0; }
.owner-note { font-size: 10px; color: var(--muted); line-height: 1.9; margin: 23px 0 0; border-top: 1px solid var(--brand-light); padding-top: 17px; }
.site-footer { display: flex; align-items: center; gap: 14px; color: var(--muted); font-size: 10px; letter-spacing: .04em; padding-bottom: max(25px, env(safe-area-inset-bottom)); }
.footer-rule { width: 22px; height: 1px; background: var(--border); }
@media (max-width: 900px) {
  .auth-layout { column-gap: 48px; grid-template-columns: 1fr 360px; }
  .auth-panel { padding-inline: 26px; }
}
@media (max-width: 720px) {
  .site-header, .auth-layout, .site-footer { width: calc(100% - 40px); }
  .site-header { padding-top: max(25px, env(safe-area-inset-top)); }
  .wordmark-cn { font-size: 25px; }
  .wordmark-en { font-size: 10px; }
  .header-caption { font-size: 11px; }
  .auth-layout { display: block; min-height: calc(100svh - 142px); padding-top: 54px; padding-bottom: 38px; }
  .auth-story { display: none; }
  .auth-panel { max-width: 420px; margin-inline: auto; padding: 30px 24px 25px; }
  .auth-description { margin-bottom: 25px; }
  h1 { font-size: 24px; }
  .site-footer { justify-content: center; font-size: 9px; flex-wrap: wrap; gap: 10px; }
  .owner-note { margin-top: 20px; }
}
@media (max-width: 350px) {
  .site-header, .auth-layout, .site-footer { width: calc(100% - 28px); }
  .auth-panel { padding-inline: 20px; }
  .wordmark { gap: 8px; }
}
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { transition: none !important; } }