:root {
  color: #1d2740;
  background: #f5f7ff;
  font-family: Inter, "PingFang SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
  background:
    radial-gradient(circle at 48% 8%, rgba(206, 207, 255, .65), transparent 31rem),
    radial-gradient(circle at 8% 96%, rgba(195, 231, 255, .56), transparent 28rem),
    linear-gradient(150deg, #fbfcff 0%, #f2f3ff 48%, #f7fbff 100%);
}

.login-layout {
  width: min(100%, 640px);
  padding: 32px 22px;
}

.login-card {
  position: relative;
  overflow: hidden;
  padding: clamp(42px, 8vw, 72px) clamp(28px, 8vw, 68px) 38px;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, .95);
  border-radius: 28px;
  background: rgba(255, 255, 255, .92);
  box-shadow: 0 28px 80px rgba(50, 58, 132, .15), 0 2px 7px rgba(42, 51, 109, .06);
}

.login-card::before, .login-card::after {
  content: "";
  position: absolute;
  z-index: -1;
  width: 190px;
  height: 190px;
  border-radius: 999px;
  filter: blur(4px);
  opacity: .28;
}
.login-card::before { top: -115px; left: -85px; background: #b7d4ff; }
.login-card::after { right: -100px; bottom: -125px; background: #dfc7ff; }

.brand-mark {
  width: 106px;
  height: 72px;
  margin: 0 auto 17px;
  display: flex;
  align-items: end;
  justify-content: center;
  gap: 3px;
  transform: skewX(-8deg);
}

.mark-piece {
  display: block;
  width: 22px;
  border-radius: 4px 4px 2px 2px;
  clip-path: polygon(0 0, 78% 0, 100% 100%, 22% 100%);
}
.mark-blue { height: 58px; background: linear-gradient(145deg, #36a7ff, #1353be); }
.mark-pink { height: 48px; background: linear-gradient(145deg, #ff4a80, #bb0e69); }
.mark-orange { height: 41px; background: linear-gradient(145deg, #ff7a2d, #ec3f1d); }
.mark-yellow { height: 52px; background: linear-gradient(145deg, #ffe33c, #f49a00); }

.brand-eyebrow {
  margin: 0 0 10px;
  color: #8490ad;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .16em;
}

h1 { margin: 0; font-size: clamp(32px, 6vw, 42px); letter-spacing: .06em; }
.login-intro { max-width: 410px; margin: 18px auto 28px; color: #6d7892; line-height: 1.75; font-size: 15px; }

.feishu-login-button {
  min-height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 11px;
  padding: 0 22px;
  border-radius: 14px;
  color: #fff;
  background: linear-gradient(120deg, #4955d8, #6573ef);
  box-shadow: 0 13px 24px rgba(76, 86, 219, .28);
  font-size: 17px;
  font-weight: 700;
  text-decoration: none;
  transition: transform .18s ease, box-shadow .18s ease;
}
.feishu-login-button:hover { transform: translateY(-2px); box-shadow: 0 17px 30px rgba(76, 86, 219, .34); }
.feishu-login-button:focus-visible { outline: 3px solid #a9b1ff; outline-offset: 4px; }
.feishu-symbol { width: 25px; height: 25px; display: grid; place-items: center; border-radius: 8px; background: #fff; color: #5665e3; font-size: 13px; }
.button-arrow { margin-left: auto; opacity: .82; }
.login-error { margin: 18px 0 0; padding: 10px 13px; border-radius: 10px; background: #fff1f1; color: #c6464d; line-height: 1.5; font-size: 13px; }
.login-note { margin: 23px 0 0; color: #9aa4b9; font-size: 12px; line-height: 1.6; }

@media (max-width: 480px) {
  .login-layout { padding: 18px 14px; }
  .login-card { border-radius: 22px; }
}