:root {
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --bg: #f3f4f6;
  --card: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --border: #e5e7eb;
}

* { box-sizing: border-box; }

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

.app-header {
  background: var(--blue);
  color: #fff;
  padding: 24px 20px 20px;
  padding-top: calc(24px + env(safe-area-inset-top));
}

.app-header h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
}

.summary {
  margin: 6px 0 0;
  opacity: 0.92;
  font-size: 14px;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px 16px 40px;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  margin-bottom: 16px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.04);
}

.card h2 {
  margin: 0 0 12px;
  font-size: 16px;
}

.field {
  display: block;
  margin-bottom: 12px;
}

.field span {
  display: block;
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 5px;
}

.field input {
  width: 100%;
  padding: 11px 12px;
  font-size: 16px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #f9fafb;
}

.field input:focus {
  outline: 2px solid var(--blue);
  outline-offset: -1px;
  background: #fff;
}

.btn-primary,
.btn-secondary {
  border: 0;
  border-radius: 10px;
  padding: 12px 16px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}

.btn-primary {
  width: 100%;
  background: var(--blue);
  color: #fff;
}

.btn-primary:active { background: var(--blue-dark); }

.btn-secondary {
  flex: 1;
  background: #eef2ff;
  color: var(--blue);
  border: 1px solid #dbeafe;
}

.form-message {
  min-height: 18px;
  margin: 10px 0 0;
  font-size: 13px;
  color: var(--muted);
}

.form-message.ok { color: #059669; }
.form-message.err { color: #dc2626; }

.tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.tab {
  flex: 1;
  padding: 10px 0;
  font-size: 14px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--muted);
  border-radius: 10px;
  cursor: pointer;
}

.tab.active {
  background: var(--blue);
  color: #fff;
  border-color: var(--blue);
}

.chart-wrap {
  position: relative;
  height: 320px;
}

.chart-empty {
  color: var(--muted);
  font-size: 14px;
  text-align: center;
  padding: 40px 0;
}

.hidden { display: none; }

.stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.stats li {
  background: #f9fafb;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 14px;
}

.stats .label {
  display: block;
  color: var(--muted);
  font-size: 12px;
  margin-bottom: 3px;
}

.data-actions {
  display: flex;
  gap: 10px;
  margin-bottom: 10px;
}

.hint {
  margin: 0;
  font-size: 12px;
  color: var(--muted);
}

code {
  background: #f3f4f6;
  padding: 1px 5px;
  border-radius: 4px;
}