:root {
  --bg: #eef2f8;
  --card: #ffffff;
  --border: #c9d2e0;
  --text: #15202e;
  --muted: #54607a;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-soft: #e7eefc;
  --accent-deep: #1e3a8a;
  --danger: #b91c1c;
  --danger-hover: #991b1b;
  --warning-bg: #fef6dc;
  --warning-border: #d4a017;
  --warning-text: #5b3d00;
  --good: #15803d;
  --good-soft: #e6f6ec;
  --bad: #b91c1c;
  --bad-soft: #fdecec;
  --tile-bg: #f4f7fc;
}

* { box-sizing: border-box; }

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

.app-header {
  background: linear-gradient(135deg, var(--accent-deep) 0%, var(--accent) 100%);
  color: #fff;
  border-bottom: 1px solid var(--accent-deep);
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  position: sticky;
  top: 0;
  z-index: 5;
  box-shadow: 0 2px 6px rgba(15, 30, 60, 0.18);
}
.app-header h1 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: 0.01em;
}
.controls {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

main {
  max-width: 80rem;
  margin: 0 auto;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.row-2col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  align-items: start;
}
.row-2col .span-2 {
  grid-row: span 2;
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-top: 3px solid var(--accent);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  box-shadow: 0 1px 2px rgba(15, 30, 60, 0.05);
}
.card h2 {
  margin: 0 0 0.75rem;
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent-deep);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
/* A second heading inside a card acts as a sub-section divider. */
.card h2:not(:first-child) {
  margin-top: 1.5rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--border);
}

.state-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(11rem, 1fr));
  gap: 0.5rem 1rem;
}
.state-grid.small {
  grid-template-columns: repeat(3, 1fr);
  margin-top: 0.75rem;
}
.state-grid.compact {
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 0.4rem 0.6rem;
}
.state-grid.compact > div {
  padding: 0.35rem 0.55rem;
}
.state-grid.compact .label {
  font-size: 0.7rem;
}
.state-grid.compact .value {
  font-size: 0.9rem;
}
.state-grid.compact .grid-last {
  grid-column: 5;
}
.state-grid > div {
  display: flex;
  flex-direction: column;
  padding: 0.5rem 0.75rem;
  background: var(--tile-bg);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 6px;
}
.state-grid .label {
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.state-grid .value {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 1rem;
  font-weight: 600;
  margin-top: 0.15rem;
  color: var(--text);
}
.value.good { color: var(--good); }
.value.bad { color: var(--bad); }

.field-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: 0.75rem 1rem;
}
.field-grid label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.85rem;
}
.field-grid label span:first-child {
  font-weight: 600;
  color: var(--text);
}
.field-grid small {
  color: var(--muted);
  font-size: 0.75rem;
}
.field-grid input,
.field-grid select {
  font: inherit;
  padding: 0.4rem 0.55rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: #fff;
  color: var(--text);
  transition: border-color 0.12s ease, box-shadow 0.12s ease;
}
.field-grid input:focus,
.field-grid select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
.field-grid input.dirty,
.field-grid select.dirty {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.action-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

/* ---------- Voltage Limits bar graph ---------- */
.vlimit-graph {
  margin-top: 1rem;
}
.vlimit-bar {
  display: flex;
  width: 100%;
  height: 1.5rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
  background: var(--tile-bg);
}
.vlimit-zone {
  height: 100%;
  transition: width 0.15s ease;
}
.vlimit-zone.uv,
.vlimit-zone.ov { background: #ef4444; }
.vlimit-zone.ok { background: #22c55e; }
.vlimit-zone.warn { background: #facc15; }
.vlimit-zone.info { background: #7dd3fc; }
.vlimit-scale {
  position: relative;
  height: 1.6rem;
  margin-top: 0.15rem;
}
/* Minor tick marks every 0.2 V (60 intervals across the 6-18 V span). */
.vlimit-scale::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background-image: repeating-linear-gradient(
    to right,
    var(--muted) 0,
    var(--muted) 1px,
    transparent 1px,
    transparent calc(100% / 60)
  );
}
.vlimit-scale span {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
  padding-top: 9px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  white-space: nowrap;
}
.vlimit-scale span::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  width: 1px;
  height: 6px;
  background: var(--muted);
}
.vlimit-scale span:first-child { transform: translateX(0); }
.vlimit-scale span:first-child::before { left: 0; }
.vlimit-scale span:last-child { transform: translateX(-100%); }
.vlimit-scale span:last-child::before { left: auto; right: 0; }
.vlimit-caption {
  text-align: center;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted);
  margin-top: 0.25rem;
}

button {
  font: inherit;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 4px;
  cursor: pointer;
}
button:hover:not(:disabled) { background: #f1f3f5; }
button:disabled { opacity: 0.5; cursor: not-allowed; }
button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
button.primary:hover:not(:disabled) { background: var(--accent-hover); }
button.danger {
  background: var(--danger);
  border-color: var(--danger);
  color: #fff;
}
button.danger:hover:not(:disabled) { background: var(--danger-hover); }
button.link {
  border: none;
  background: transparent;
  color: var(--accent);
  padding: 0;
  font-size: 0.85rem;
  text-decoration: underline;
}

#status {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color: rgba(255, 255, 255, 0.92);
  font-size: 0.9rem;
}

.header-sep {
  color: rgba(255, 255, 255, 0.55);
  font-size: 0.9rem;
}
#header-fwver {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color: rgba(255, 255, 255, 0.92);
  font-size: 0.9rem;
}
#header-fwver .header-fwlabel {
  color: rgba(255, 255, 255, 0.7);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

.card h2 .header-note {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--muted);
  margin-left: 0.5rem;
}

.app-header .controls button {
  background: rgba(255, 255, 255, 0.95);
  color: var(--accent-deep);
  border-color: rgba(255, 255, 255, 0.95);
  font-weight: 600;
}
.app-header .controls button:hover:not(:disabled) {
  background: #fff;
}
.app-header .controls button:disabled {
  background: rgba(255, 255, 255, 0.35);
  color: rgba(255, 255, 255, 0.85);
  border-color: transparent;
}

.muted { color: var(--muted); font-size: 0.85rem; }

.warning-banner {
  background: var(--warning-bg);
  border: 1px solid var(--warning-border);
  color: var(--warning-text);
  padding: 0.6rem 0.8rem;
  border-radius: 6px;
  font-size: 0.85rem;
  margin: 0 0 0.75rem;
}

.calset-card {
  border-color: var(--warning-border);
  border-top-color: var(--warning-border);
}
.calset-card h2 { color: var(--warning-text); }

.log {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.8rem;
  background: #111;
  color: #ddd;
  padding: 0.6rem 0.75rem;
  border-radius: 4px;
  height: 14rem;
  overflow-y: auto;
  white-space: pre-wrap;
}
.log[hidden] { display: none; }

.modal {
  position: fixed;
  inset: 0;
  background: rgba(20, 25, 35, 0.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 1rem;
}
.modal[hidden] { display: none; }
.modal-card {
  background: #fff;
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  min-width: 22rem;
  max-width: 36rem;
  width: 100%;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.25);
}
.modal-card.warning { border-top: 4px solid var(--danger); }
.modal-card h2 { margin-top: 0; }
.modal-card ul { padding-left: 1.2rem; }
.modal-card pre {
  background: #f4f5f7;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.5rem 0.75rem;
  font-size: 0.8rem;
  white-space: pre-wrap;
}
.modal-actions {
  display: flex;
  gap: 0.6rem;
  justify-content: flex-end;
  margin-top: 1rem;
}

/* Firmware update modal */
.fwupdate-card {
  max-width: 40rem;
  border-top: 4px solid var(--accent);
}
.fwupdate-card ol {
  padding-left: 1.2rem;
  margin: 0.5rem 0 0.75rem;
}
.fwupdate-card ol li { margin-bottom: 0.25rem; }
.fwupdate-card code {
  background: #f4f5f7;
  padding: 0.05rem 0.3rem;
  border-radius: 3px;
  font-size: 0.85em;
}
.fwupdate-phase[hidden] { display: none; }
.fwupdate-file-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin: 0.5rem 0 0.25rem;
}
.fwupdate-file-row input[type="file"] {
  flex: 1;
  padding: 0.4rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: #fff;
}
#fwupdate-progress {
  width: 100%;
  height: 1.25rem;
  margin: 0.5rem 0;
  appearance: none;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
  background: #f4f5f7;
}
#fwupdate-progress::-webkit-progress-bar { background: #f4f5f7; }
#fwupdate-progress::-webkit-progress-value {
  background: linear-gradient(90deg, var(--accent), var(--accent-deep));
  transition: width 0.15s ease-out;
}
#fwupdate-progress::-moz-progress-bar {
  background: var(--accent);
}
#fwupdate-status {
  font-weight: 600;
  margin-bottom: 0.25rem;
}
#fwupdate-result {
  background: #f4f5f7;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.75rem 1rem;
  margin: 0.5rem 0;
  white-space: normal;
}
#fwupdate-result code {
  background: #fff;
  border: 1px solid var(--border);
  padding: 0.1rem 0.35rem;
  border-radius: 3px;
  font-size: 0.85em;
  word-break: break-all;
}