/* 3d-research — notebook stylesheet
   Warm-paper study notebook: single readable column, serif prose,
   interactive figures in cards. No build step, no webfonts. */

:root {
  --paper:  #f7f2e7;
  --card:   #fffdf6;
  --ink:    #26241f;
  --muted:  #7d766a;
  --line:   #e4dbc6;
  --accent: #b0532c;   /* terracotta */
  --blue:   #315b7d;
  --olive:  #6b7a3a;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  font-size: 17px;
  line-height: 1.68;
}

main { max-width: 780px; margin: 0 auto; padding: 1.25rem 1.25rem 6rem; }

/* ---- header / nav ---- */
header.nb {
  border-bottom: 1px solid var(--line);
  background: var(--card);
}
header.nb .inner {
  max-width: 780px; margin: 0 auto; padding: .65rem 1.25rem;
  display: flex; align-items: baseline; gap: .75rem;
  font-family: ui-sans-serif, system-ui, sans-serif; font-size: .85rem;
}
header.nb a { color: var(--muted); text-decoration: none; }
header.nb a:hover { color: var(--accent); }
header.nb .brand { font-weight: 700; color: var(--ink); letter-spacing: .02em; }
header.nb .lang { margin-left: auto; white-space: nowrap; }
header.nb .lang .cur { font-weight: 700; color: var(--accent); }

h1 { font-size: 1.85rem; line-height: 1.25; margin: 1.6rem 0 .4rem; }
h2 { font-size: 1.3rem; margin-top: 2.2rem; }
h3 { font-size: 1.05rem; margin-top: 1.6rem; }
.kicker {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: .78rem; letter-spacing: .14em; text-transform: uppercase;
  color: var(--accent); font-weight: 700;
}
.subtitle { color: var(--muted); margin-top: 0; }

a { color: var(--blue); }
strong { color: var(--ink); }
hr { border: 0; border-top: 1px solid var(--line); margin: 2.5rem 0; }

code, pre {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: .86em;
  background: #efe8d8; border-radius: 4px;
}
code { padding: .1em .35em; }
pre { padding: .8rem 1rem; overflow-x: auto; line-height: 1.5; }
pre code { background: none; padding: 0; }

/* ---- callouts ---- */
.callout {
  border-left: 3px solid var(--accent);
  background: #f2e9d6;
  padding: .7rem 1rem; margin: 1.25rem 0;
  border-radius: 0 8px 8px 0;
}
.callout.blue { border-left-color: var(--blue); background: #e9edf2; }
.callout .tag { font-weight: 700; font-family: ui-sans-serif, system-ui, sans-serif; font-size: .8rem; }

/* ---- interactive figure cards ---- */
figure.demo {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 1rem;
  margin: 1.8rem 0;
  box-shadow: 0 1px 3px rgba(60,50,30,.06);
}
figure.demo canvas { display: block; width: 100%; border-radius: 8px; background: #f3eddd; }
figure.demo figcaption {
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: .82rem; color: var(--muted); margin-top: .7rem;
}
figure.demo figcaption b { color: var(--accent); }

.controls {
  display: flex; flex-wrap: wrap; gap: .5rem 1.4rem; align-items: center;
  margin-top: .8rem;
  font-family: ui-sans-serif, system-ui, sans-serif; font-size: .82rem;
}
.controls label { display: flex; align-items: center; gap: .45rem; color: var(--muted); }
.controls input[type="range"] { width: 110px; accent-color: var(--accent); }
.controls input[type="checkbox"], .controls input[type="radio"] { accent-color: var(--accent); }
.controls .val { font-variant-numeric: tabular-nums; color: var(--ink); min-width: 2.6em; }
.controls button {
  font: inherit; padding: .3rem .8rem; border-radius: 6px; cursor: pointer;
  border: 1px solid var(--line); background: var(--paper); color: var(--ink);
}
.controls button:hover { border-color: var(--accent); color: var(--accent); }
.controls button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.controls button.primary:hover { filter: brightness(1.08); color: #fff; }

.readout {
  font-family: ui-monospace, Consolas, monospace; font-size: .78rem;
  color: var(--muted); margin-top: .5rem; white-space: pre-wrap;
}

/* ---- tables ---- */
table { border-collapse: collapse; width: 100%; margin: 1.25rem 0; font-size: .95em; }
th, td { border: 1px solid var(--line); padding: .45rem .65rem; text-align: left; vertical-align: top; }
th { background: #efe8d8; font-family: ui-sans-serif, system-ui, sans-serif; font-size: .82rem; }

/* ---- index cards ---- */
ul.toc { list-style: none; padding: 0; margin: 1.5rem 0; display: grid; gap: .8rem; }
ul.toc li a {
  display: flex; gap: 1rem; align-items: baseline;
  background: var(--card); border: 1px solid var(--line); border-radius: 10px;
  padding: .85rem 1.1rem; text-decoration: none; color: var(--ink);
  transition: border-color .15s;
}
ul.toc li a:hover { border-color: var(--accent); }
ul.toc .num {
  font-family: ui-sans-serif, system-ui, sans-serif; font-weight: 800;
  color: var(--accent); font-size: 1.05rem; min-width: 2em;
}
ul.toc .t { font-weight: 650; }
ul.toc .d { color: var(--muted); font-size: .88em; display: block; }
ul.toc li.soon a { opacity: .5; pointer-events: none; }

/* ---- experiment logbook (experiments/) ---- */
.callout.abbandonata { border-left-color: #8a8577; background: #eee9dc; }
.callout.abbandonata .tag { color: #8a8577; }
.callout.sorpresa { border-left-color: var(--olive); background: #edf0e2; }
.callout.sorpresa .tag { color: var(--olive); }
figure.demo img { display: block; width: 100%; border-radius: 8px; border: 1px solid var(--line); }
.scheda dt {
  font-weight: 700; font-family: ui-sans-serif, system-ui, sans-serif; font-size: .8rem;
  color: var(--muted); text-transform: uppercase; letter-spacing: .08em; margin-top: .6rem;
}
.scheda dd { margin: 0; }
.data {
  font-family: ui-sans-serif, system-ui, sans-serif; font-size: .78rem; font-weight: 700;
  color: var(--accent); letter-spacing: .06em;
}

/* ---- prev/next footer ---- */
nav.pn {
  display: flex; justify-content: space-between; gap: 1rem;
  margin-top: 3.5rem; padding-top: 1.25rem; border-top: 1px solid var(--line);
  font-family: ui-sans-serif, system-ui, sans-serif; font-size: .85rem;
}
nav.pn a { text-decoration: none; }

/* KaTeX display spacing */
.katex-display { margin: 1.1rem 0; }