:root {
  --bg: #f4f4f2;
  --fg: #1b1b1b;
  --muted: #6b6b6b;
  --line: #d8d8d4;
  --card: #ffffff;
  --accent: #1b1b1b;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  padding: 2rem 1rem 4rem;
  background: var(--bg);
  color: var(--fg);
  font: 15px/1.5 -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

.app {
  max-width: 640px;
  margin: 0 auto;
  display: grid;
  gap: 1.25rem;
}

h1 { font-size: 1.5rem; margin: 0 0 .35rem; }
header p { margin: 0; color: var(--muted); }

.panel, .result {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 1rem;
}

.tabs { display: flex; gap: .5rem; margin-bottom: 1rem; }

.tab {
  flex: 1;
  padding: .55rem;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: transparent;
  font: inherit;
  color: var(--muted);
  cursor: pointer;
}
.tab.is-active { background: var(--accent); border-color: var(--accent); color: #fff; }

.pane { display: grid; gap: .75rem; }

label { display: grid; gap: .3rem; }
label > span { font-size: .8rem; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; }

select, input[type=number] {
  padding: .5rem;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: #fff;
  font: inherit;
  color: inherit;
}

.result {
  display: flex;
  gap: 1.25rem;
  align-items: center;
  flex-wrap: wrap;
}

.preview svg {
  display: block;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: #fff;
}

.readout { margin: 0; display: grid; grid-template-columns: auto; gap: .1rem; min-width: 12rem; }
.readout dt { font-size: .75rem; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; }
.readout dd { margin: 0 0 .6rem; }
.mono { font-family: ui-monospace, Consolas, monospace; letter-spacing: .12em; word-break: break-all; }

.print-controls { display: grid; gap: .75rem; }
.print-controls label { max-width: 8rem; }

button.primary, #download {
  padding: .6rem 1rem;
  border-radius: 7px;
  border: 1px solid var(--line);
  background: #fff;
  font: inherit;
  cursor: pointer;
}
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }

.hint { margin: 0; font-size: .8rem; color: var(--muted); }
footer { font-size: .8rem; color: var(--muted); }