:root {
  color-scheme: light;
  --bg: #eef2f6;
  --panel: #ffffff;
  --text: #18202f;
  --muted: #667085;
  --line: #d8dee8;
  --accent: #0f766e;
  --accent-dark: #115e59;
  --accent-soft: #d9f4ef;
  --warning: #b45309;
  --danger: #b42318;
  --shadow: 0 22px 60px rgba(18, 28, 45, 0.14);
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
}

body {
  margin: 0;
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "Microsoft YaHei", sans-serif;
  background:
    linear-gradient(135deg, rgba(15, 118, 110, 0.12), transparent 34%),
    linear-gradient(315deg, rgba(37, 99, 235, 0.1), transparent 42%),
    var(--bg);
  color: var(--text);
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 32px 16px;
}

.tool-panel {
  width: min(720px, 100%);
  background: rgba(255, 255, 255, 0.95);
  border: 1px solid rgba(216, 222, 232, 0.9);
  border-radius: 8px;
  box-shadow: var(--shadow);
  padding: clamp(22px, 5vw, 44px);
}

.panel-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 30px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 6vw, 3.5rem);
  line-height: 1.02;
  letter-spacing: 0;
}

.status-pill {
  flex: 0 0 auto;
  border: 1px solid var(--accent-soft);
  background: var(--accent-soft);
  color: var(--accent-dark);
  border-radius: 999px;
  padding: 8px 12px;
  font-size: 0.85rem;
  font-weight: 700;
  white-space: nowrap;
}

.secret-form {
  display: grid;
  gap: 10px;
}

label,
.code-label {
  color: var(--muted);
  font-size: 0.92rem;
  font-weight: 700;
}

.secret-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 48px;
  gap: 10px;
}

input {
  min-width: 0;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 15px 16px;
  background: #fbfcfe;
  color: var(--text);
  outline: none;
  transition:
    border-color 0.18s ease,
    box-shadow 0.18s ease,
    background 0.18s ease;
}

input:focus {
  border-color: var(--accent);
  background: #ffffff;
  box-shadow: 0 0 0 4px rgba(15, 118, 110, 0.14);
}

.icon-button,
.primary-button,
.secondary-button {
  min-height: 48px;
  border-radius: 8px;
  border: 1px solid transparent;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 800;
}

.icon-button {
  background: #f7f9fc;
  border-color: var(--line);
  color: var(--muted);
}

button svg {
  width: 20px;
  height: 20px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.field-help {
  margin: 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.code-area {
  display: grid;
  grid-template-columns: 168px minmax(0, 1fr);
  align-items: center;
  gap: clamp(22px, 5vw, 42px);
  margin: 36px 0 24px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
}

.countdown-ring {
  position: relative;
  width: 168px;
  aspect-ratio: 1;
}

.countdown-ring svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.ring-track,
.ring-progress {
  fill: none;
  stroke-width: 10;
}

.ring-track {
  stroke: #e1e7ef;
}

.ring-progress {
  stroke: var(--accent);
  stroke-linecap: round;
  stroke-dasharray: 326.73;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.2s linear;
}

.time-left {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  align-content: center;
  gap: 2px;
  color: var(--muted);
}

.time-left strong {
  color: var(--text);
  font-size: 3rem;
  line-height: 1;
  letter-spacing: 0;
}

.time-left span {
  font-weight: 700;
}

.code-box {
  min-width: 0;
}

.code-label {
  margin: 0 0 10px;
}

.code-value {
  min-height: 76px;
  display: flex;
  align-items: center;
  color: var(--text);
  font-size: clamp(3rem, 11vw, 5.25rem);
  font-weight: 900;
  letter-spacing: 0;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  word-break: break-word;
}

.code-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 18px;
}

.primary-button,
.secondary-button {
  padding: 0 18px;
}

.primary-button {
  background: var(--accent);
  color: #ffffff;
}

.primary-button:hover:not(:disabled) {
  background: var(--accent-dark);
}

.primary-button:disabled {
  cursor: not-allowed;
  opacity: 0.48;
}

.secondary-button {
  background: #ffffff;
  border-color: var(--line);
  color: var(--text);
}

.message {
  min-height: 24px;
  color: var(--muted);
  font-weight: 650;
}

.message.error {
  color: var(--danger);
}

.message.warn {
  color: var(--warning);
}

@media (max-width: 640px) {
  .panel-head,
  .code-area {
    grid-template-columns: 1fr;
  }

  .panel-head {
    display: grid;
  }

  .code-area {
    justify-items: center;
    padding: 22px 16px;
  }

  .code-box {
    width: 100%;
    text-align: center;
  }

  .code-value {
    justify-content: center;
  }

  .code-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .primary-button,
  .secondary-button {
    width: 100%;
  }
}