:root {
  --ink: #1f2328;
  --muted: #59636e;
  --line: #d1d9e0;
  --bg: #ffffff;
  --panel: #f6f8fa;
  --accent: #0969da;
  --pass: #1a7f37;
  --fail: #cf222e;
}

* { box-sizing: border-box; }

body {
  margin: 0 auto;
  max-width: 68rem;
  padding: 1.5rem 1rem 4rem;
  font: 15px/1.55 system-ui, -apple-system, "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
}

header h1 { margin: 0 0 .25rem; font-size: 1.6rem; }
.tagline { margin: 0 0 1.5rem; color: var(--muted); }

h2 { margin: 0 0 .75rem; font-size: 1.15rem; }
h3 { margin: 1.25rem 0 .5rem; font-size: 1rem; }
a { color: var(--accent); }
code { font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: .9em; }

.panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1rem 1.25rem 1.25rem;
  margin-bottom: 1rem;
  background: var(--panel);
}
.panel.error { border-color: var(--fail); background: #fff5f5; }

.dropzone {
  border: 2px dashed var(--line);
  border-radius: 8px;
  padding: .75rem 1rem;
  background: var(--bg);
  text-align: center;
}
.dropzone.over { border-color: var(--accent); background: #f0f6ff; }
.dropzone p { margin: .25rem 0; }

.row { display: flex; flex-wrap: wrap; gap: .5rem; align-items: center; margin-top: .75rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); gap: .75rem; }

.field { display: flex; flex-direction: column; gap: .25rem; margin-top: .75rem; }
.field > span { font-size: .85rem; color: var(--muted); }
input, select, textarea {
  font: inherit;
  color: inherit;
  padding: .4rem .5rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg);
}
textarea, pre { font-family: ui-monospace, SFMono-Regular, Consolas, monospace; font-size: .82rem; }
textarea { width: 100%; resize: vertical; }

button {
  font: inherit;
  padding: .4rem .8rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg);
  cursor: pointer;
}
button:hover { border-color: var(--accent); color: var(--accent); }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
button.primary:hover { color: #fff; opacity: .9; }
.link { color: var(--accent); cursor: pointer; text-decoration: underline; }

.hint, .report { color: var(--muted); font-size: .85rem; }
.report { margin: .5rem 0 0; font-family: ui-monospace, SFMono-Regular, Consolas, monospace; }

.badge { font-weight: 600; margin: 0 0 .5rem; }
.badge.pass { color: var(--pass); }
.badge.fail { color: var(--fail); }

.warnings { color: #9a6700; font-size: .9rem; }
.warnings p { margin: .25rem 0; }

pre {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: .75rem;
  overflow-x: auto;
  margin: 0;
}

table.coefficients { border-collapse: collapse; width: 100%; background: var(--bg); }
table.coefficients td, table.coefficients th {
  border: 1px solid var(--line);
  padding: .25rem .5rem;
  text-align: right;
  font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
  font-size: .85rem;
}
table.coefficients th { background: var(--panel); }

details { margin-top: .75rem; }
summary { cursor: pointer; color: var(--muted); }

footer { margin-top: 2rem; color: var(--muted); font-size: .85rem; }

svg.plot { background: var(--bg); border: 1px solid var(--line); border-radius: 6px; }