:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --border: #e2e5ea;
  --text: #1a1d23;
  --muted: #6b7280;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --error-bg: #fef2f2;
  --error-border: #fca5a5;
  --error-text: #dc2626;
  --success: #16a34a;
  --radius: 10px;
  --shadow: 0 1px 4px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);

  /* brand colours */
  --visa: #1a1f71;
  --mastercard: #eb001b;
  --amex: #007bc1;
  --discover: #e67621;
  --default-brand: #374151;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 3rem 1rem 4rem;
}

.container {
  width: 100%;
  max-width: 540px;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

header { text-align: center; }
h1 { font-size: 2rem; font-weight: 700; letter-spacing: -.5px; }
.subtitle { margin-top: .4rem; color: var(--muted); font-size: .95rem; }

/* Form */
#lookup-form { display: flex; flex-direction: column; gap: .75rem; }

.input-row {
  display: flex;
  gap: .5rem;
}

input[type="text"] {
  flex: 1;
  padding: .7rem 1rem;
  font-size: 1.05rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  outline: none;
  transition: border-color .15s;
  letter-spacing: .08em;
}
input[type="text"]:focus { border-color: var(--accent); }

button[type="submit"] {
  padding: .7rem 1.4rem;
  font-size: 1rem;
  font-weight: 600;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  white-space: nowrap;
  transition: background .15s, opacity .15s;
}
button[type="submit"]:hover { background: var(--accent-hover); }
button[type="submit"]:disabled { opacity: .6; cursor: not-allowed; }

.error {
  padding: .6rem .9rem;
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  border-radius: calc(var(--radius) - 2px);
  color: var(--error-text);
  font-size: .9rem;
}

/* Result card */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  animation: fadeUp .25s ease;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.card-header {
  padding: 1rem 1.25rem;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: .75rem;
}

.brand-badge {
  display: inline-block;
  padding: .25rem .7rem;
  border-radius: 6px;
  font-size: .85rem;
  font-weight: 700;
  letter-spacing: .04em;
  color: #fff;
  background: var(--default-brand);
}
.brand-badge.visa        { background: var(--visa); }
.brand-badge.mastercard  { background: var(--mastercard); }
.brand-badge.amex        { background: var(--amex); }
.brand-badge.discover    { background: var(--discover); }

.bin-label {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: .12em;
  color: var(--text);
}

.result-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  padding: .5rem 0;
}

.field {
  padding: .65rem 1.25rem;
  border-bottom: 1px solid var(--border);
}
.field:nth-last-child(-n+2) { border-bottom: none; }

.field dt {
  font-size: .75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--muted);
  margin-bottom: .2rem;
}
.field dd {
  font-size: .95rem;
  color: var(--text);
  word-break: break-word;
}
.field dd a {
  color: var(--accent);
  text-decoration: none;
}
.field dd a:hover { text-decoration: underline; }

.source-badge {
  display: inline-block;
  padding: .15rem .5rem;
  border-radius: 4px;
  font-size: .78rem;
  font-weight: 600;
  background: #e0f2fe;
  color: #0369a1;
}
.source-badge.db    { background: #d1fae5; color: #065f46; }
.source-badge.cache { background: #fef3c7; color: #92400e; }

@media (max-width: 480px) {
  .result-grid { grid-template-columns: 1fr; }
  .field { border-bottom: 1px solid var(--border) !important; }
  .field:last-child { border-bottom: none !important; }
}

/* ── API Docs ─────────────────────────────────────────────── */
.api-docs {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  padding-top: .5rem;
}

.docs-heading {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: .07em;
  padding-bottom: .75rem;
  border-bottom: 1px solid var(--border);
}

.endpoint {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: .85rem;
}

.ep-title {
  display: flex;
  align-items: center;
  gap: .6rem;
}

.method {
  display: inline-block;
  padding: .2rem .55rem;
  border-radius: 5px;
  font-size: .75rem;
  font-weight: 700;
  letter-spacing: .05em;
}
.method.get { background: #dcfce7; color: #15803d; }

.ep-path {
  font-size: .95rem;
  font-weight: 600;
  color: var(--text);
  background: var(--bg);
  padding: .2rem .5rem;
  border-radius: 5px;
  border: 1px solid var(--border);
}

.ep-desc {
  font-size: .88rem;
  color: var(--muted);
  line-height: 1.5;
}

.ep-label {
  font-size: .73rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--muted);
  margin-bottom: -.4rem;
}

.params-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .85rem;
}
.params-table th {
  text-align: left;
  font-size: .72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .05em;
  color: var(--muted);
  padding: .35rem .5rem;
  border-bottom: 1px solid var(--border);
}
.params-table td {
  padding: .4rem .5rem;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  vertical-align: top;
}
.params-table tr:last-child td { border-bottom: none; }
.params-table code {
  font-size: .82rem;
  background: var(--bg);
  padding: .1rem .35rem;
  border-radius: 4px;
  border: 1px solid var(--border);
}

.req-badge {
  display: inline-block;
  font-size: .68rem;
  font-weight: 600;
  padding: .05rem .35rem;
  border-radius: 4px;
  background: #fef2f2;
  color: var(--error-text);
  border: 1px solid var(--error-border);
  vertical-align: middle;
  margin-left: .25rem;
}

.code-block {
  background: #f1f3f7;
  border: 1px solid var(--border);
  border-radius: calc(var(--radius) - 2px);
  padding: .75rem 1rem;
  font-size: .8rem;
  font-family: "SF Mono", "Fira Code", "Cascadia Code", monospace;
  color: #1e293b;
  overflow-x: auto;
  white-space: pre;
  line-height: 1.6;
}

.status-table { margin-top: -.2rem; }

.tiers-block {
  display: flex;
  flex-direction: column;
  gap: .6rem;
}