:root {
  color-scheme: light;
  --bg: #f6f7fb;
  --ink: #0b1120;
  --muted: #5b6472;
  --line: #e2e6f0;
  --brand: #7b8cff;
  --brand-ink: #5a63ff;
  --ok: #12855e;
  --err: #c0392b;
  --card: #ffffff;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font: 15px/1.6 -apple-system, BlinkMacSystemFont, "PingFang SC",
        "Segoe UI", "Microsoft YaHei", sans-serif;
  min-height: 100vh;
}
.page { max-width: 420px; margin: 0 auto; padding: 48px 20px; }
.brand {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--ink); text-decoration: none; font-weight: 700; font-size: 18px;
}
.brand .dot { width: 10px; height: 10px; border-radius: 50%; background: var(--brand); }
h1 { font-size: 24px; margin: 28px 0 4px; }
.sub { color: var(--muted); margin: 0 0 24px; }
.field-hint { margin: -6px 0 14px; font-size: 13px; color: var(--muted); }
.card {
  background: var(--card); border: 1px solid var(--line); border-radius: 14px;
  padding: 22px;
  box-shadow: 0 8px 24px rgba(11, 17, 32, .05);
}
label { display: block; margin-bottom: 14px; }
label span { display: block; font-size: 13px; color: var(--muted); margin-bottom: 6px; }
input {
  width: 100%; padding: 10px 12px; font-size: 15px;
  border: 1px solid var(--line); border-radius: 10px; background: #fff;
  color: var(--ink);
}
input:focus { outline: none; border-color: var(--brand); box-shadow: 0 0 0 3px rgba(123,140,255,.18); }
.code-row { display: flex; gap: 10px; }
.code-row input { flex: 1; }
.code-send {
  flex: none; padding: 0 14px; font-size: 14px; white-space: nowrap;
  color: var(--brand-ink); background: none;
  border: 1px solid var(--brand); border-radius: 10px; cursor: pointer;
}
.code-send:disabled { opacity: .55; cursor: default; border-color: var(--line); color: var(--muted); }
.cta {
  width: 100%; margin-top: 6px; padding: 12px; font-size: 15px; font-weight: 600;
  color: #fff; background: var(--brand); border: 0; border-radius: 10px; cursor: pointer;
}
.cta:hover { background: var(--brand-ink); }
.cta:disabled { opacity: .55; cursor: default; }
.link {
  display: block; margin: 12px auto 0; padding: 4px; background: none; border: 0;
  color: var(--brand-ink); cursor: pointer; font-size: 14px;
}
.hint { color: var(--muted); font-size: 13px; margin: 8px 0 0; }
.result .ok { color: var(--ok); font-weight: 600; }
.err {
  margin-top: 14px; padding: 12px 14px; border-radius: 10px;
  background: #fdf0ee; color: var(--err); border: 1px solid #f2d2cc;
}
/* 平台登录 row: a divider + the configured provider buttons. */
.divider {
  display: flex; align-items: center; gap: 12px; margin: 22px 0 14px;
  color: var(--muted); font-size: 13px; text-align: center;
}
.divider::before, .divider::after {
  content: ""; flex: 1; height: 1px; background: var(--line);
}
.oauth { display: flex; flex-wrap: wrap; gap: 10px; }
.oauth-btn {
  flex: 1; min-width: 120px; padding: 11px 14px; text-align: center;
  border: 1px solid var(--line); border-radius: 10px; background: var(--card);
  color: var(--ink); font-size: 14px; font-weight: 600; text-decoration: none;
  transition: border-color .12s ease, box-shadow .12s ease;
}
.oauth-btn:hover { border-color: var(--brand); box-shadow: 0 0 0 3px rgba(123,140,255,.14); }
.foot { margin-top: 20px; color: var(--muted); font-size: 13px; text-align: center; }
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1420; --ink: #e8ecf5; --muted: #98a0b3;
    --line: #262e40; --card: #171e2e; --brand: #7b8cff; --brand-ink: #9aa8ff;
    --err: #ff8a80;
  }
  input { background: #0f1420; color: var(--ink); }
}