/* discopt-doe browser app. Light/dark aware, no external assets. */

:root {
  --bg: #fbfbfa;
  --surface: #ffffff;
  --border: #e3e1dc;
  --text: #1f1e1c;
  --muted: #6b6862;
  --accent: #b8563c;
  --accent-fg: #ffffff;
  --ok: #2f6f4e;
  --err-bg: #fdf0ed;
  --err-fg: #8c3520;
  --code-bg: #f3f1ed;
  --radius: 10px;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #191817;
    --surface: #222120;
    --border: #38352f;
    --text: #eceae5;
    --muted: #9d988e;
    --accent: #d9765a;
    --accent-fg: #1a0f0c;
    --ok: #6fbf94;
    --err-bg: #3a201a;
    --err-fg: #f0a894;
    --code-bg: #2a2825;
  }
}

* { box-sizing: border-box; }

/* The `hidden` attribute is honoured by a UA-stylesheet rule, which any author
   rule setting `display` outranks — `.boot { display: flex }` alone was enough
   to leave a hidden status line (and its spinner) on screen forever. Author
   rules do not get to lose this argument. */
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-text-size-adjust: 100%;
}

.wrap { max-width: 60rem; margin: 0 auto; padding: 0 1.25rem; }

/* ── masthead ─────────────────────────────────────────────── */

.masthead {
  border-bottom: 1px solid var(--border);
  padding: 2.5rem 0 1.75rem;
  margin-bottom: 2rem;
}
.masthead h1 {
  margin: 0 0 .35rem;
  font-size: clamp(1.75rem, 4vw, 2.4rem);
  letter-spacing: -.02em;
}
.tagline { margin: 0; color: var(--muted); max-width: 46rem; }

.boot {
  display: flex; align-items: center; gap: .6rem;
  margin: 1.1rem 0 0; font-size: .9rem; color: var(--muted);
}
.boot.done { color: var(--ok); }
.boot.failed { color: var(--err-fg); }

.spinner {
  width: 1em; height: 1em; flex: none;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}
.boot.done .spinner, .boot.failed .spinner { display: none; }
@keyframes spin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .spinner { animation-duration: 3s; } }

/* ── cards ────────────────────────────────────────────────── */

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.75rem;
}
.card h2 {
  margin: 0 0 1.25rem;
  font-size: 1.15rem;
  display: flex; align-items: center; gap: .6rem;
}
.step {
  display: inline-grid; place-items: center;
  width: 1.6rem; height: 1.6rem;
  background: var(--accent); color: var(--accent-fg);
  border-radius: 50%; font-size: .85rem; font-weight: 600;
}

.field { margin-bottom: 1.35rem; }
.field > label {
  display: block; margin-bottom: .4rem;
  font-weight: 600; font-size: .9rem;
}
.row-between { display: flex; justify-content: space-between; align-items: baseline; gap: 1rem; }

.hint { margin: .45rem 0 0; color: var(--muted); font-size: .85rem; }
.hint.next-step { margin-top: .9rem; }

/* ── controls ─────────────────────────────────────────────── */

select, input[type="text"], input[type="number"] {
  font: inherit;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: .45rem .6rem;
  width: 100%;
  min-width: 0;
}
select { max-width: 30rem; }
input:focus-visible, select:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

button {
  font: inherit; font-weight: 500;
  border-radius: 7px;
  padding: .5rem 1rem;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}
button:hover:not(:disabled) { border-color: var(--accent); }
button:disabled { opacity: .45; cursor: not-allowed; }
button.primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
button.ghost { padding: .2rem .55rem; font-size: .85rem; }

.actions { display: flex; flex-wrap: wrap; gap: .6rem; align-items: center; }

.opts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(11rem, 1fr));
  gap: .85rem;
}
.opt label { display: block; font-size: .82rem; color: var(--muted); margin-bottom: .25rem; }
.opt.check { display: flex; align-items: center; gap: .45rem; align-self: end; }
.opt.check input { width: auto; }
.opt.check label { margin: 0; }

/* ── tables ───────────────────────────────────────────────── */

.grid { width: 100%; border-collapse: collapse; }
.grid th, .grid td {
  text-align: left;
  padding: .4rem .5rem;
  border-bottom: 1px solid var(--border);
  font-size: .9rem;
}
.grid th { font-weight: 600; font-size: .8rem; color: var(--muted); }
.grid td input { padding: .3rem .45rem; }
.grid .drop-col { width: 2.5rem; }

.data { font-variant-numeric: tabular-nums; }
.data td { font-family: var(--mono); font-size: .82rem; }
.data th { position: sticky; top: 0; background: var(--surface); }

.scroll { overflow-x: auto; max-height: 22rem; overflow-y: auto; margin-top: .75rem; }

.summary { margin: .9rem 0 0; font-size: .9rem; }
.summary strong { font-family: var(--mono); }

/* ── upload ───────────────────────────────────────────────── */

.drop {
  border: 1.5px dashed var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: border-color .15s, background .15s;
}
.drop.over { border-color: var(--accent); background: var(--code-bg); }
.drop input[type="file"] { font-size: .9rem; max-width: 100%; }

/* ── results ──────────────────────────────────────────────── */

.alert {
  background: var(--err-bg); color: var(--err-fg);
  border-radius: 7px; padding: .75rem .9rem;
  margin-top: 1rem; font-size: .9rem;
}
.alert pre {
  margin: .5rem 0 0; white-space: pre-wrap;
  font-family: var(--mono); font-size: .78rem; opacity: .8;
}
.alert p { margin: 0; }
.alert-title { font-weight: 600; }
.alert p.alert-why { margin-top: .35rem; font-family: var(--mono); font-size: .82rem; }
.alert ul { margin: .55rem 0 0; padding-left: 1.1rem; }
.alert li + li { margin-top: .3rem; }

#design-source { margin-bottom: 1.35rem; }
#design-source .note { margin-top: 0; }

/* A caveat that qualifies a result rather than replacing it. */
.note {
  border-left: 3px solid var(--border);
  padding: .1rem 0 .1rem .8rem;
  margin: .9rem 0;
  color: var(--muted); font-size: .85rem;
}
.note p { margin: 0; }
.note p + p { margin-top: .3rem; }
.note-title { font-weight: 600; color: var(--text); }

#analyze-status { margin: 1rem 0 0; }
/* No margin while the download button is still hidden, so the card does not
   end in a band of empty space before a workbook has been analyzed. */
.analyzed-actions:has(button:not([hidden])) { margin-top: 1.25rem; }

/* The model written out. Long equations scroll rather than wrapping mid-term. */
.equation {
  background: var(--code-bg);
  border-radius: 7px;
  padding: .6rem .75rem;
  margin: .75rem 0;
  overflow-x: auto;
}
.equation p {
  margin: 0;
  font-family: var(--mono); font-size: .85rem;
  white-space: nowrap;
}
.equation p + p { margin-top: .3rem; color: var(--muted); }

/* ANOVA verdicts. The ✓/✗ carries the meaning; colour only reinforces it. */
.data td.yes { color: var(--ok); font-weight: 600; }
.data td.no { color: var(--err-fg); }

.result-block { margin-top: 1.5rem; }
.result-block h3 { margin: 0 0 .25rem; font-size: .95rem; }
.result-block h4 { margin: 1.5rem 0 .25rem; font-size: .9rem; }
.result-block .hint { margin-bottom: .6rem; }

.stats { display: flex; flex-wrap: wrap; gap: 1.5rem; margin: .75rem 0; }
.stat .k { display: block; font-size: .75rem; color: var(--muted); }
.stat .v { font-family: var(--mono); font-size: 1.05rem; }

code { background: var(--code-bg); padding: .1em .35em; border-radius: 4px; font-size: .88em; }

footer { padding: 1rem 0 3rem; }
footer a { color: var(--accent); }

@media (max-width: 34rem) {
  .card { padding: 1.1rem; }
  .actions button { flex: 1 1 auto; }
}

/* ── model editor ─────────────────────────────────────────── */

textarea {
  font-family: var(--mono);
  font-size: .9rem;
  width: 100%;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: .5rem .6rem;
  resize: vertical;
}
textarea:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

.feedback { margin-top: .6rem; font-size: .85rem; }
.feedback:empty { display: none; }
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--err-fg); }
.feedback .derivs {
  margin: .4rem 0 0;
  padding: .5rem .65rem;
  background: var(--code-bg);
  border-radius: 6px;
  font-family: var(--mono);
  font-size: .78rem;
  color: var(--text);
  overflow-x: auto;
  white-space: pre;
}