:root {
  --bg: #f4f5f7;
  --surface: #ffffff;
  --text: #16181d;
  --text-dim: #6b7280;
  --border: #e5e7eb;
  --accent: #2563eb;
  --accent-dim: #dbeafe;
  --danger: #dc2626;
  --ok: #16a34a;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(16,24,40,.04), 0 1px 3px rgba(16,24,40,.06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --surface: #1a1d24;
    --text: #f1f2f4;
    --text-dim: #9aa1ac;
    --border: #2a2e37;
    --accent: #5b8def;
    --accent-dim: #1b2942;
    --danger: #f87171;
    --ok: #4ade80;
    --shadow: 0 1px 2px rgba(0,0,0,.3), 0 2px 8px rgba(0,0,0,.25);
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 16px;
  padding-top: max(14px, env(safe-area-inset-top));
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}

.topbar h1 {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  font-weight: 700;
  margin: 0;
}

.icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  color: var(--accent);
}

.topbar nav {
  display: flex;
  gap: 8px;
}

.topbar nav a, .topbar nav button {
  font-size: 13px;
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-dim);
  text-decoration: none;
  cursor: pointer;
}

.topbar nav a:hover, .topbar nav button:hover {
  background: var(--accent-dim);
  color: var(--accent);
}

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 16px;
  padding-bottom: 48px;
}

.hero-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 12px;
  margin-bottom: 20px;
}

.hero-card {
  background: linear-gradient(135deg, var(--accent), #7c3aed);
  border: none;
  color: #fff;
}

.hero-label {
  font-size: 13px;
  opacity: .85;
  margin-bottom: 8px;
}

.hero-value {
  font-size: 34px;
  font-weight: 800;
  line-height: 1.1;
}

.hero-value .unit {
  font-size: 16px;
  font-weight: 600;
  opacity: .85;
  margin-left: 4px;
}

.hero-cost {
  margin-top: 10px;
  font-size: 18px;
  font-weight: 700;
  opacity: .95;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
  margin-bottom: 24px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 16px;
}

.stat-card .label {
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.stat-card .value {
  font-size: 26px;
  font-weight: 700;
  line-height: 1.1;
}

.stat-card .value .unit {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-dim);
  margin-left: 2px;
}

.stat-card .meta {
  margin-top: 8px;
  font-size: 11px;
  color: var(--text-dim);
}

.stat-card.stale .value { color: var(--text-dim); }
.stat-card .meta.err { color: var(--danger); }

.section-title {
  font-size: 14px;
  font-weight: 700;
  margin: 0 0 12px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: .04em;
}

.chart-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

select, input, button {
  font-family: inherit;
  font-size: 14px;
}

select, input[type=text], input[type=number], input[type=password] {
  padding: 9px 10px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
}

.range-btns { display: flex; gap: 6px; }

.range-btns button {
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-dim);
  cursor: pointer;
}

.range-btns button.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.chart-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 16px;
  height: 280px;
}

/* login page */
.login-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}

.login-card {
  width: 100%;
  max-width: 340px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px 24px;
}

.login-card h1 {
  font-size: 18px;
  margin: 0 0 4px;
}

.login-card p.sub {
  font-size: 13px;
  color: var(--text-dim);
  margin: 0 0 20px;
}

.field {
  margin-bottom: 14px;
}

.field label {
  display: block;
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 6px;
}

.field input {
  width: 100%;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-dim);
  margin-bottom: 16px;
  cursor: pointer;
}

.checkbox-row input {
  width: 16px;
  height: 16px;
  accent-color: var(--accent);
}

.btn-primary {
  width: 100%;
  padding: 11px;
  border-radius: 10px;
  border: none;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

.btn-primary:active { opacity: .85; }

.error-msg {
  color: var(--danger);
  font-size: 13px;
  margin: 10px 0 0;
  min-height: 16px;
}

/* settings */
.pin-row {
  display: grid;
  grid-template-columns: 70px 1fr 70px 36px;
  gap: 8px;
  margin-bottom: 8px;
  align-items: center;
}

.pin-row input { width: 100%; }

.btn-ghost {
  padding: 9px 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  cursor: pointer;
}

.btn-icon {
  background: transparent;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 16px;
}

.row-actions {
  display: flex;
  gap: 10px;
  margin-top: 16px;
}

.hint {
  font-size: 12px;
  color: var(--text-dim);
  margin: 6px 0 16px;
}

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--text);
  color: var(--bg);
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 13px;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s;
}

.toast.show { opacity: 1; }