:root {
  color-scheme: light;
  --bg: #f6f7f9;
  --card: #ffffff;
  --border: #e2e5ea;
  --text: #1a1d23;
  --muted: #6b7280;
  --accent: #2563eb;
  --danger: #dc2626;
  --danger-bg: #fef2f2;
  --success: #16a34a;
}

* {
  box-sizing: border-box;
}

/* .center-screen's `display: flex` otherwise overrides the browser's
   default `[hidden] { display: none }` rule (author CSS always beats
   user-agent defaults, regardless of specificity), so an element with
   both `hidden` and a display-setting class stays visible. */
[hidden] {
  display: none !important;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.muted {
  color: var(--muted);
}

.center-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 32px;
  width: 320px;
  text-align: center;
}

button {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 600;
  background: var(--accent);
  color: white;
}

button.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
  font-weight: 500;
}

button:disabled {
  opacity: 0.5;
  cursor: default;
}

.error {
  color: var(--danger);
  font-size: 13px;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  background: var(--card);
  border-bottom: 1px solid var(--border);
}

header h1 {
  font-size: 18px;
  margin: 0;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.stats {
  display: flex;
  gap: 16px;
  padding: 20px 24px 0;
}

.stat-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 20px;
  min-width: 140px;
}

.stat-card-warn .stat-value {
  color: var(--danger);
}

.stat-value {
  font-size: 26px;
  font-weight: 700;
}

.stat-label {
  font-size: 12px;
  color: var(--muted);
  margin-top: 4px;
}

.tabs {
  display: flex;
  gap: 4px;
  padding: 20px 24px 0;
}

.tab-btn {
  background: transparent;
  color: var(--muted);
  border-radius: 8px 8px 0 0;
  border: 1px solid transparent;
}

.tab-btn.active {
  background: var(--card);
  color: var(--text);
  border-color: var(--border);
  border-bottom-color: var(--card);
}

.tab-panel {
  background: var(--card);
  margin: 0 24px 24px;
  border: 1px solid var(--border);
  border-radius: 0 10px 10px 10px;
  padding: 16px;
}

.panel-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

th, td {
  text-align: left;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
}

th {
  color: var(--muted);
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}

.badge-sent {
  background: #ecfdf5;
  color: var(--success);
}

.badge-failed {
  background: var(--danger-bg);
  color: var(--danger);
}

.error-cell {
  color: var(--danger);
  max-width: 260px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text);
  color: white;
  padding: 10px 18px;
  border-radius: 8px;
  font-size: 13px;
}

.toast.error {
  background: var(--danger);
}