*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0f172a;
  --surface: #1e293b;
  --border: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --green: #22c55e;
  --red: #ef4444;
  --yellow: #eab308;
  --night: #6366f1;
  --offpeak: #3b82f6;
  --peak: #f59e0b;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  display: flex;
  justify-content: center;
  padding: 1rem;
}

#app {
  width: 100%;
  max-width: 480px;
}

/* ── Header ─────────────────────────────────────────────── */
header {
  text-align: center;
  padding: 1.5rem 0 1rem;
}
header h1 {
  font-size: 1.4rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}
header .bolt { font-size: 1.6rem; }
.subtitle {
  color: var(--muted);
  font-size: 0.8rem;
  margin-top: 0.15rem;
}

/* ── Cards ──────────────────────────────────────────────── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem;
  margin-bottom: 1rem;
}
.card h2 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin-bottom: 0.75rem;
}

/* ── Summary card ───────────────────────────────────────── */
.summary-value {
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1;
}
.summary-unit { font-size: 1rem; color: var(--muted); font-weight: 400; }
.summary-compare {
  margin-top: 0.5rem;
  font-size: 0.95rem;
  color: var(--muted);
}
.summary-compare .up { color: var(--red); font-weight: 600; }
.summary-compare .down { color: var(--green); font-weight: 600; }
.summary-compare .flat { color: var(--yellow); font-weight: 600; }
.data-lag {
  font-size: 0.8rem;
  opacity: 0.6;
}

/* ── Breakdown rows ─────────────────────────────────────── */
.breakdown {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.breakdown-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
}
.breakdown-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}
.breakdown-dot.night { background: var(--night); }
.breakdown-dot.offpeak { background: var(--offpeak); }
.breakdown-dot.peak { background: var(--peak); }
.breakdown-label { flex: 1; color: var(--muted); }
.breakdown-value { font-weight: 600; }

/* ── Chart ──────────────────────────────────────────────── */
.chart-container {
  position: relative;
  height: 220px;
  width: 100%;
}
.chart-toggle {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 0.75rem;
}
.toggle-btn {
  flex: 1;
  padding: 0.35rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: transparent;
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s;
}
.toggle-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

/* ── Forms ──────────────────────────────────────────────── */
.form-group {
  margin-bottom: 1rem;
}
.form-group label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.3rem;
}
.form-group input {
  width: 100%;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 1rem;
}
.form-group input:focus {
  outline: none;
  border-color: var(--primary);
}
.optional {
  font-weight: 400;
  font-size: 0.75rem;
  color: var(--muted);
  opacity: 0.7;
}

.btn {
  width: 100%;
  padding: 0.7rem;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  background: var(--primary);
  color: #fff;
  transition: background 0.15s;
}
.btn:hover { background: var(--primary-hover); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }

.btn-sm {
  width: auto;
  padding: 0.45rem 1rem;
  font-size: 0.85rem;
}

.error {
  color: var(--red);
  font-size: 0.85rem;
  margin-top: 0.5rem;
}
.success {
  color: var(--green);
  font-size: 0.85rem;
  margin-top: 0.5rem;
}

.link-btn {
  background: none;
  border: none;
  color: var(--primary);
  cursor: pointer;
  font-size: 0.9rem;
  margin-top: 0.5rem;
}
.muted-text {
  color: var(--muted);
  font-size: 0.9rem;
}
.help-text {
  color: var(--muted);
  font-size: 0.85rem;
  margin-bottom: 0.75rem;
}

/* ── Actions row ────────────────────────────────────────── */
.actions {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}
.actions .btn { flex: 1; }

/* ── Install banner ─────────────────────────────────────── */
#install-banner {
  text-align: center;
  border-color: var(--primary);
  border-style: dashed;
}
.install-text {
  color: var(--muted);
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

/* ── Utilities ──────────────────────────────────────────── */
.hidden { display: none !important; }
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mb-1 { margin-bottom: 0.5rem; }

/* ── Loading spinner ────────────────────────────────────── */
.spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  vertical-align: middle;
  margin-right: 0.4rem;
}
@keyframes spin { to { transform: rotate(360deg); } }