:root {
  --bg: #050816;
  --bg-elevated: #0f172a;
  --accent: #38bdf8;
  --accent-soft: rgba(56, 189, 248, 0.18);
  --text: #e5e7eb;
  --text-muted: #9ca3af;
  --danger: #f97373;
  --success: #4ade80;
  --card-radius: 18px;
  --shadow-soft: 0 22px 45px rgba(15, 23, 42, 0.85);
  --transition-fast: 0.2s ease-out;
}

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

html,
body {
  height: 100%;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 0 0, #1d4ed8 0, transparent 50%),
    radial-gradient(circle at 100% 0, #22c55e 0, transparent 50%),
    radial-gradient(circle at 50% 100%, #0f172a 0, #020617 60%);
}

body {
  display: flex;
  align-items: stretch;
  justify-content: center;
}

.app {
  width: 100%;
  max-width: 960px;
  padding: 20px 18px 24px;
}

/* Header */

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 14px;
}

.title-group h1 {
  margin: 0;
  font-size: 1.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.subtitle {
  margin: 4px 0 0;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Buttons */

.primary-btn {
  border: none;
  outline: none;
  cursor: pointer;
  padding: 10px 18px;
  border-radius: 999px;
  background: linear-gradient(135deg, #0ea5e9, #22c55e);
  color: #0b1120;
  font-weight: 600;
  font-size: 0.9rem;
  box-shadow: 0 12px 25px rgba(56, 189, 248, 0.4);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition:
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    opacity var(--transition-fast);
}

.primary-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 16px 32px rgba(56, 189, 248, 0.5);
}

.primary-btn:active {
  transform: translateY(0);
  box-shadow: 0 8px 18px rgba(56, 189, 248, 0.35);
}

/* Status bar */

.status-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 18px;
}

.status-pill {
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid rgba(148, 163, 184, 0.25);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.status-pill span {
  color: var(--text);
}

.status-label {
  font-weight: 600;
}

.status-disconnected {
  color: var(--danger);
}

.status-connected {
  color: var(--success);
}

/* Layout principale */

.grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
}

@media (max-width: 900px) {
  .grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 640px) {
  .app {
    padding-inline: 14px;
  }

  .app-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .grid {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* Cards */

.card {
  background:
    radial-gradient(circle at 0 0, rgba(56, 189, 248, 0.08), transparent 55%),
    radial-gradient(circle at 100% 100%, rgba(56, 189, 248, 0.06), transparent 45%),
    rgba(15, 23, 42, 0.92);
  border-radius: var(--card-radius);
  padding: 16px 16px 18px;
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(148, 163, 184, 0.22);
  position: relative;
  overflow: hidden;
}

.card::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 0 0, rgba(148, 163, 184, 0.15), transparent 55%);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
}

.card:hover::after {
  opacity: 1;
}

.card h2 {
  margin: 0 0 10px;
  font-size: 1rem;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

/* SoC gauge */

.soc-card {
  grid-column: span 2;
}

@media (max-width: 900px) {
  .soc-card {
    grid-column: span 2;
  }
}

@media (max-width: 640px) {
  .soc-card {
    grid-column: span 1;
  }
}

.soc-gauge {
  display: flex;
  align-items: center;
  justify-content: center;
  padding-top: 6px;
}

.circular-chart {
  max-width: 140px;
  max-height: 140px;
}

.circle-bg {
  fill: none;
  stroke: #1e293b;
  stroke-width: 3.4;
}

.circle {
  fill: none;
  stroke-width: 3.4;
  stroke-linecap: round;
  stroke: url(#grad) #38bdf8;
  transform: rotate(-90deg);
  transform-origin: center;
  transition:
    stroke-dasharray 0.4s ease-out,
    stroke 0.3s ease-out;
}

.percentage {
  fill: var(--text);
  font-size: 0.66rem;
  font-weight: 600;
  text-anchor: middle;
}

/* Valori numerici */

.value-row {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin-top: 6px;
}

.big-value {
  font-size: 2.45rem;
  font-weight: 600;
}

.unit {
  font-size: 1.1rem;
  color: var(--text-muted);
}

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

/* Footer */

.app-footer {
  margin-top: 18px;
  font-size: 0.75rem;
  color: var(--text-muted);
  opacity: 0.8;
}