:root {
  --bg-a: #F3F4EF;
  --bg-b: #E4ECE7;
  --surface: #FFFFFF;
  --ink: #1C2420;
  --ink-soft: #5B655F;
  --ink-faint: #8A928B;
  --accent: #2E6E5C;
  --accent-strong: #1F4F41;
  --accent-soft: #DCEAE4;
  --border: #DBDCD2;
  --danger: #B3432F;
  --danger-soft: #F7E7E2;
  --shadow: 0 1px 2px rgba(28,36,32,0.05), 0 20px 48px rgba(28,36,32,0.10);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-a: #141815;
    --bg-b: #1B221C;
    --surface: #1B211D;
    --ink: #E9E7DE;
    --ink-soft: #A2ABA3;
    --ink-faint: #6C756E;
    --accent: #5FBFA0;
    --accent-strong: #8AD6BC;
    --accent-soft: #22352E;
    --border: #2B332E;
    --danger: #E28B78;
    --danger-soft: #34221D;
    --shadow: 0 1px 2px rgba(0,0,0,0.4), 0 20px 48px rgba(0,0,0,0.45);
  }
}
:root[data-theme="dark"] {
  --bg-a: #141815;
  --bg-b: #1B221C;
  --surface: #1B211D;
  --ink: #E9E7DE;
  --ink-soft: #A2ABA3;
  --ink-faint: #6C756E;
  --accent: #5FBFA0;
  --accent-strong: #8AD6BC;
  --accent-soft: #22352E;
  --border: #2B332E;
  --danger: #E28B78;
  --danger-soft: #34221D;
  --shadow: 0 1px 2px rgba(0,0,0,0.4), 0 20px 48px rgba(0,0,0,0.45);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  background:
    repeating-linear-gradient(
      135deg,
      rgba(46,110,92,0.045) 0px, rgba(46,110,92,0.045) 1px,
      transparent 1px, transparent 34px
    ),
    radial-gradient(circle at 18% 12%, var(--bg-b), transparent 55%),
    radial-gradient(circle at 85% 85%, var(--bg-b), transparent 45%),
    var(--bg-a);
  color: var(--ink);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
}

.wrap { width: 100%; max-width: 380px; }

.brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 28px;
}

.mark {
  width: 44px;
  height: 44px;
  border-radius: 11px;
  background: linear-gradient(155deg, var(--accent), var(--accent-strong));
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  flex: none;
  box-shadow: 0 4px 10px rgba(31,79,65,0.28);
}
.mark span { display: block; height: 3px; border-radius: 2px; background: rgba(255,255,255,0.92); }
.mark span:nth-child(1) { width: 20px; }
.mark span:nth-child(2) { width: 14px; }
.mark span:nth-child(3) { width: 17px; }

.brand-text { font-weight: 700; font-size: 1.55rem; letter-spacing: -0.01em; }
.brand-text small {
  display: block;
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--ink-faint);
  letter-spacing: 0.02em;
  margin-top: 2px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  padding: 32px 30px 28px;
}

.card h1 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 8px;
}

.card .sub {
  font-size: 0.85rem;
  color: var(--ink-soft);
  margin: 0 0 22px;
}

label {
  display: block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--ink-faint);
  margin: 0 0 6px;
}
.field { margin-bottom: 16px; }

input[type=text], input[type=password] {
  width: 100%;
  padding: 11px 13px;
  border: 1px solid var(--border);
  border-radius: 9px;
  font-size: 0.96rem;
  background: var(--bg-a);
  color: var(--ink);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
input[type=text]:focus, input[type=password]:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

input.code-input {
  letter-spacing: 0.5em;
  font-variant-numeric: tabular-nums;
  text-align: center;
  font-size: 1.2rem;
}

button {
  width: 100%;
  margin-top: 6px;
  padding: 16px 16px;
  border: none;
  border-radius: 9px;
  background: var(--accent);
  color: #fff;
  font-size: 0.96rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.05s ease;
}
button:hover { background: var(--accent-strong); }
button:active { transform: translateY(1px); }

.error {
  background: var(--danger-soft);
  color: var(--danger);
  border: 1px solid var(--danger);
  border-radius: 9px;
  padding: 10px 13px;
  font-size: 0.85rem;
  margin-bottom: 18px;
}

.credit {
  text-align: center;
  margin: 6px 0 0;
  font-size: 0.72rem;
  color: var(--ink-faint);
}

.foot {
  text-align: center;
  margin-top: 22px;
  font-size: 0.76rem;
  color: var(--ink-faint);
}

.qr-box {
  display: flex;
  justify-content: center;
  margin-bottom: 18px;
}
.qr-box img {
  width: 190px;
  height: 190px;
  border-radius: 10px;
  border: 1px solid var(--border);
  padding: 10px;
  background: #fff;
}

.manual-key {
  text-align: center;
  margin-bottom: 22px;
}
.manual-key .key {
  display: inline-block;
  margin-top: 6px;
  font-family: "Cascadia Code", "SF Mono", Consolas, monospace;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  background: var(--bg-a);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 12px;
  color: var(--ink);
  word-break: break-all;
}

.steps {
  font-size: 0.86rem;
  color: var(--ink-soft);
  margin: 0 0 20px;
  padding-left: 20px;
}
.steps li { margin-bottom: 4px; }

@media (prefers-reduced-motion: reduce) {
  input, button { transition: none; }
}