/* Layout: controls column on the left, map and results on the right; one column on phones. */
:root {
  --paper: #f3f5f8;
  --surface: #ffffff;
  --ink: #18202c;
  --ink-muted: #5b6676;
  --rule: #e1e6ee;
  --rule-strong: #b9c2cf;
  --accent: #0b6e99;
  --zero: #16a34a;
  --invalid: #d13b3b;
  --charge-1: #ef4b4b;
  --charge-2: #3b8bff;

  --font-ui: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-data: "JetBrains Mono", ui-monospace, "SFMono-Regular", Consolas, monospace;
  --radius: 10px;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0f1218;
    --surface: #171b23;
    --ink: #e6e9ef;
    --ink-muted: #98a2b3;
    --rule: #262c38;
    --rule-strong: #3a4352;
    --accent: #4cc3f0;
    --zero: #5ee08a;
    --invalid: #ff6b6b;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --paper: #0f1218;
  --surface: #171b23;
  --ink: #e6e9ef;
  --ink-muted: #98a2b3;
  --rule: #262c38;
  --rule-strong: #3a4352;
  --accent: #4cc3f0;
  --zero: #5ee08a;
  --invalid: #ff6b6b;
  color-scheme: dark;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 14px/1.45 var(--font-ui);
  padding-block: 20px 32px;
  padding-left: max(16px, env(safe-area-inset-left, 0px));
  padding-right: max(16px, env(safe-area-inset-right, 0px));
}

h1,
h2 {
  margin: 0;
  text-wrap: balance;
}

h1 {
  font-size: 1.5rem;
  font-weight: 600;
}

h2 {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.page-header {
  max-width: 1280px;
  margin: 0 auto 18px;
}

.page-header p {
  margin: 4px 0 0;
  color: var(--ink-muted);
  max-width: 70ch;
}

/* ---------- Layout ---------- */

.layout {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.controls,
.results {
  display: grid;
  gap: 14px;
  min-width: 0;
}

@media (max-width: 860px) {
  .layout {
    grid-template-columns: minmax(0, 1fr);
  }
}

.panel,
.map-card {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  padding: 14px;
  display: grid;
  gap: 10px;
}

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

/* ---------- Form controls ---------- */

input[type="number"],
select,
button {
  font: inherit;
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  border-radius: 6px;
  padding: 4px 6px;
}

input[type="number"] {
  width: 7.5em;
  font-family: var(--font-data);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

input.is-invalid {
  border-color: var(--invalid);
  outline: 1px solid var(--invalid);
}

button {
  cursor: pointer;
  padding: 4px 10px;
}

button:hover {
  border-color: var(--accent);
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  flex-wrap: wrap;
}

.charge {
  border: 1px solid var(--rule);
  border-radius: 8px;
  margin: 0;
  padding: 8px 10px 10px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.charge legend {
  padding: 0 4px;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 6px;
}

.charge label {
  display: flex;
  align-items: center;
  gap: 4px;
  font-family: var(--font-data);
}

.charge label input {
  width: 100%;
  min-width: 0;
}

.charge .charge-q {
  grid-column: 1 / -1;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.dot-1 {
  background: var(--charge-1);
}

.dot-2 {
  background: var(--charge-2);
}

.layers {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px 10px;
}

.layers label {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
}

.layers input {
  accent-color: var(--accent);
}

/* ---------- Map ---------- */

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}

.toolbar-buttons {
  display: flex;
  gap: 6px;
}

#zoom-in,
#zoom-out {
  width: 32px;
  padding: 4px 0;
  font-weight: 600;
}

.colorbar {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-data);
  font-size: 12px;
  color: var(--ink-muted);
}

.colorbar-gradient {
  width: 140px;
  height: 10px;
  border-radius: 3px;
  background: linear-gradient(90deg, #000004, #420a68, #932667, #dd513a, #fca50a, #fcffa4);
}

.map {
  display: block;
  width: min(100%, 82vh);
  margin-inline: auto;
  max-width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: 6px;
  cursor: grab;
  touch-action: none;
}

.map.is-over-charge {
  cursor: pointer;
}

.map.is-panning,
.map.is-dragging-charge {
  cursor: grabbing;
}

.readout,
.zero-table {
  margin: 0;
  display: grid;
  gap: 6px 16px;
}

.readout {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.readout div,
.zero-table div {
  min-width: 0;
}

dt {
  font-size: 12px;
  color: var(--ink-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

dd {
  margin: 0;
  font-family: var(--font-data);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  overflow-wrap: anywhere;
}

.notes {
  margin: 0;
  color: var(--invalid);
  font-size: 13px;
}

/* ---------- E = 0 and plot ---------- */

.zero-table {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

@media (max-width: 640px) {
  .zero-table {
    grid-template-columns: minmax(0, 1fr);
  }
}

.mark {
  width: 12px;
  height: 12px;
  display: inline-block;
}

.mark-ring {
  border: 2px solid var(--zero);
  border-radius: 50%;
}

.mark-cross {
  background:
    linear-gradient(45deg, transparent 42%, var(--zero) 42%, var(--zero) 58%, transparent 58%),
    linear-gradient(-45deg, transparent 42%, var(--zero) 42%, var(--zero) 58%, transparent 58%);
}

.axis-plot {
  display: block;
  width: 100%;
  height: 240px;
}