:root {
  --bg: #f4f4f5;
  --card: #ffffff;
  --border: #d4d4d8;
  --border-soft: #e4e4e7;
  --ink: #18181b;
  --ink-soft: #52525b;
  --ink-faint: #a1a1aa;
  --white: #ffffff;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: 'Inter', -apple-system, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--ink);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

.wrap { max-width: 640px; margin: 0 auto; padding: 24px 16px 48px; }

/* Topbar */
.topbar { margin-bottom: 24px; }
.logo { font-size: 20px; font-weight: 700; letter-spacing: -0.02em; }
.logo-mark {
  display: inline-block; background: var(--ink); color: var(--white);
  padding: 2px 8px; border-radius: 6px; margin-right: 6px; font-size: 15px;
}

/* Cards */
.card {
  background: var(--card); border: 1px solid var(--border-soft);
  border-radius: 12px; padding: 24px; margin-bottom: 16px;
}
.card h2 { font-size: 17px; font-weight: 600; letter-spacing: -0.01em; }
.card-head {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; margin-bottom: 16px;
}

/* Form elements */
input[type="text"] {
  width: 100%; font: inherit; font-size: 14px; color: var(--ink);
  background: var(--card); border: 1px solid var(--border);
  border-radius: 8px; padding: 12px 14px; margin-top: 12px;
  transition: border-color 0.15s;
}
input[type="text"]:focus { outline: none; border-color: var(--ink); }
input::placeholder { color: var(--ink-faint); }

.check-row { display: flex; gap: 8px; align-items: stretch; }
.check-row input { flex: 1; }

.btn {
  font: inherit; font-weight: 600; font-size: 14px;
  padding: 10px 18px; border-radius: 8px; cursor: pointer;
  border: 1px solid transparent; transition: background 0.15s, border-color 0.15s, opacity 0.15s;
  display: inline-flex; align-items: center; justify-content: center; white-space: nowrap;
}
.btn-primary { background: var(--ink); color: var(--white); }
.btn-primary:hover { background: #000; }
.btn-ghost { background: var(--card); color: var(--ink); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--ink); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }
.btn-small { padding: 6px 12px; font-size: 13px; font-weight: 500; margin-top: 0; }

.status { font-size: 13px; margin-top: 12px; min-height: 18px; color: var(--ink-soft); }
.status.err { color: #b91c1c; }

/* Result */
.code-box {
  background: var(--bg); border: 1px solid var(--border-soft);
  border-radius: 10px; padding: 24px; text-align: center;
}
.sms-text { font-size: 15px; color: var(--ink); }
.sms-text.empty { color: var(--ink-faint); font-size: 15px; font-weight: 500; }
.sms-code {
  font-size: 40px; font-weight: 700; letter-spacing: 0.08em;
  font-variant-numeric: tabular-nums; word-break: break-all;
}
.sms-time { font-size: 13px; color: var(--ink-soft); margin-top: 6px; }
.sms-expiry { font-size: 12px; color: var(--ink-faint); margin-top: 10px; }

.turnstile { display: flex; justify-content: center; margin-top: 14px; min-height: 65px; }

.foot { text-align: center; font-size: 12px; color: var(--ink-faint); margin-top: 24px; }

@media (max-width: 520px) {
  .check-row { flex-wrap: wrap; }
  .check-row input { flex-basis: 100%; }
  .check-row .btn { flex: 1; }
  .sms-code { font-size: 32px; }
}