:root {
  --bg: #f4f5fb;
  --bg-gradient: radial-gradient(circle at top left, #eef0ff 0%, #f4f5fb 45%, #f4f5fb 100%);
  --surface: #ffffff;
  --surface-2: #f8f9ff;
  --border: #e3e5f5;
  --text: #1b1d2b;
  --text-muted: #6b6f8d;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --primary-soft: #eef0ff;
  --danger: #ef4444;
  --danger-soft: #fef2f2;
  --success: #22c55e;
  --shadow: 0 10px 30px -12px rgba(30, 32, 60, 0.15);
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
}

:root[data-theme='dark'] {
  --bg: #0f1117;
  --bg-gradient: radial-gradient(circle at top left, #191c2b 0%, #0f1117 55%, #0f1117 100%);
  --surface: #171a26;
  --surface-2: #1d2030;
  --border: #2a2e42;
  --text: #eef0fb;
  --text-muted: #9498b8;
  --primary: #818cf8;
  --primary-hover: #6366f1;
  --primary-soft: #232744;
  --danger: #f87171;
  --danger-soft: #2a1a1c;
  --success: #4ade80;
  --shadow: 0 10px 30px -12px rgba(0, 0, 0, 0.5);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  background: var(--bg-gradient);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
  transition: background 0.25s ease, color 0.25s ease;
}

.wrapper {
  max-width: 880px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 36px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text);
  text-decoration: none;
}

.brand img {
  width: 32px;
  height: 32px;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px 14px;
  border-radius: 999px;
  cursor: pointer;
  font-size: 0.85rem;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease;
}

.theme-toggle:hover {
  transform: translateY(-1px);
}

.icon-sun, .icon-moon {
  display: none;
}

:root[data-theme='light'] .icon-sun { display: inline; }
:root[data-theme='dark'] .icon-moon { display: inline; }

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

.card + .card {
  margin-top: 24px;
}

h1.title {
  font-size: 1.6rem;
  margin: 0 0 4px;
}

.subtitle {
  color: var(--text-muted);
  margin: 0 0 24px;
  font-size: 0.95rem;
}

label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

textarea {
  width: 100%;
  resize: vertical;
  min-height: 140px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  font-size: 0.9rem;
  line-height: 1.5;
}

textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.hint {
  margin: 8px 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.form-actions {
  display: flex;
  gap: 12px;
  margin-top: 18px;
}

.btn {
  border: none;
  border-radius: 999px;
  padding: 11px 22px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: transform 0.15s ease, background 0.15s ease;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
}

.btn-ghost:hover {
  color: var(--text);
  border-color: var(--text-muted);
}

.results-section {
  margin-top: 28px;
}

.results-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 14px;
}

.results-heading h2 {
  font-size: 1rem;
  margin: 0;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}

.otp-card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px 18px;
}

.otp-card-error {
  background: var(--danger-soft);
  border-color: var(--danger);
}

.otp-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.otp-label {
  font-weight: 600;
  font-size: 0.9rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 65%;
}

.otp-countdown {
  font-size: 0.78rem;
  color: var(--primary);
  background: var(--primary-soft);
  padding: 2px 10px;
  border-radius: 999px;
  font-variant-numeric: tabular-nums;
}

.otp-code-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.otp-code {
  font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;
  font-size: 1.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

.btn-copy {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  padding: 8px;
  cursor: pointer;
  display: inline-flex;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.btn-copy:hover {
  color: var(--primary);
  border-color: var(--primary);
}

.btn-copy.copied {
  color: var(--success);
  border-color: var(--success);
}

.otp-secret {
  margin-top: 10px;
  font-size: 0.72rem;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.otp-error {
  font-size: 0.85rem;
  color: var(--danger);
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 8px;
  padding: 40px 20px;
  color: var(--text-muted);
}

.empty-state svg {
  opacity: 0.5;
  margin-bottom: 8px;
}

.instructions-card {
  margin-top: 24px;
}

.instructions-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.1rem;
  margin: 0 0 14px;
  color: var(--primary);
}

.instructions-text {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
  margin: 0 0 10px;
}

.instructions-subheading {
  color: var(--text);
  font-weight: 600;
  margin-bottom: 6px;
}

.instructions-list {
  margin: 0 0 14px;
  padding-left: 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.8;
}

.instructions-tip {
  font-size: 0.85rem;
  color: var(--text);
  background: var(--primary-soft);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  margin: 0;
}

footer.page-footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.78rem;
  margin-top: 32px;
}

@media (max-width: 560px) {
  .wrapper {
    padding: 20px 14px 60px;
  }
  .card {
    padding: 20px;
  }
}