:root {
  --paper: #f5f5f0;
  --ink: #20231f;
  --muted: #62665d;
  --line: #ced1c7;
  --accent: #d6f45b;
  --mono: 'SFMono-Regular', Consolas, 'Liberation Mono', monospace;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 30px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 1rem;
  line-height: 1.65;
}
a { color: inherit; text-underline-offset: 4px; }
a:hover { text-decoration-thickness: 2px; }
::selection { background: var(--accent); color: var(--ink); }
:focus-visible { outline: 3px solid #527200; outline-offset: 5px; }
.wrap { width: min(960px, calc(100% - 80px)); margin-inline: auto; }
.skip { position: fixed; top: -100px; left: 20px; padding: 12px; background: var(--accent); color: var(--ink); z-index: 10; }
.skip:focus { top: 12px; }
.header { display: grid; grid-template-columns: 1fr auto auto; align-items: center; gap: 24px; padding-block: 10px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 12px; font-size: 1.375rem; font-weight: 600; text-decoration: none; letter-spacing: -.5px; }
/* Official micro mark: about 26px visible height. Its internal margins plus
   20px padding exceed one M-width of clear space on all sides. */
.mit-home { display: block; padding: 20px; }
.mit-home img { display: block; width: 64px; height: auto; }
nav { display: flex; gap: 28px; font-size: .875rem; }
nav a { padding-block: 8px; text-decoration: none; }
nav a:hover { text-decoration: underline; }
.intro { padding-block: 52px 56px; }
.eyebrow { font: .75rem/1.5 var(--mono); letter-spacing: 1px; text-transform: uppercase; color: var(--muted); }
.intro > .eyebrow { display: inline-block; background: var(--accent); color: var(--ink); padding: 4px 8px; }
h1 { font-size: clamp(2.25rem, 4.8vw, 3.5rem); line-height: 1.12; letter-spacing: -1.8px; font-weight: 500; margin: 25px 0; }
h1 em { font-family: Georgia, 'Times New Roman', serif; font-weight: 400; }
.about-copy { margin-top: 32px; }
.about-copy h2 { display: flex; align-items: center; gap: 16px; font-size: 1.0625rem; font-weight: 600; line-height: 1.5; letter-spacing: 0; color: var(--ink); }
.about-copy h2::after { content: ''; flex: 0 1 64px; height: 1px; background: var(--line); }
.lead { color: var(--muted); font-size: 1rem; line-height: 1.75; max-width: 82ch; margin: 16px 0 0; }
h2 { font-size: 1.5rem; font-weight: 500; letter-spacing: -.6px; margin: 0; }
.section-heading { display: flex; justify-content: space-between; align-items: center; padding-bottom: 20px; }
.work { padding-bottom: 42px; }
.week { border-top: 1px solid var(--line); }
.week:last-of-type { border-bottom: 1px solid var(--line); }
summary { display: grid; grid-template-columns: 45px 1fr 75px 20px; gap: 20px; align-items: baseline; padding-block: 24px; cursor: pointer; list-style: none; }
summary::-webkit-details-marker { display: none; }
summary:hover .week-title { text-decoration: underline; text-underline-offset: 5px; }
.number { font: 1.125rem var(--mono); color: var(--muted); }
.week-info { min-width: 0; }
.week-title { display: block; font-size: 1.125rem; }
.week-status { display: block; margin-top: 4px; color: var(--muted); font-size: .875rem; line-height: 1.5; }
.date { font: .75rem var(--mono); color: var(--muted); text-align: right; }
.toggle { font: 1.25rem var(--mono); text-align: center; transition: transform .15s; }
details[open] .toggle { transform: rotate(45deg); }
.entry { padding: 0 40px 22px 65px; max-width: 800px; color: var(--muted); }
.entry p { margin: 0 0 12px; }
.entry p:last-child { margin-bottom: 0; }
.entry a { color: var(--ink); }
.media-card { margin: 18px 0 22px; }
.media-card img { display: block; width: 100%; height: auto; border: 1px solid var(--line); background: #fff; }
.media-card figcaption { margin-top: 8px; color: var(--muted); font-size: .8125rem; line-height: 1.55; }
.media-card figcaption strong { color: var(--ink); font-weight: 600; }
.photo-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; margin: 18px 0 22px; align-items: start; }
.photo-grid .media-card { margin: 0; }
.small-note { font-size: .875rem; color: var(--muted); margin-top: 20px; }
.project { display: grid; grid-template-columns: 1fr 1fr; gap: 35px; padding: 30px; background: #e9eddf; border-left: 2px solid #7e9250; }
.project h2 { margin-top: 8px; font-size: 2rem; }
.project p { color: var(--muted); margin: 0; align-self: center; }
.footer { display: flex; flex-wrap: wrap; align-items: baseline; justify-content: space-between; gap: 10px 24px; border-top: 1px solid var(--line); margin-top: 48px; padding-block: 24px 30px; color: var(--muted); font: .75rem/1.65 var(--mono); }
@media (max-width: 640px) {
  .wrap { width: calc(100% - 40px); }
  .header { grid-template-columns: 1fr auto; padding-block: 0 16px; gap: 0 18px; }
  .mit-home { grid-column: 2; grid-row: 1; }
  .brand { font-size: 1.25rem; gap: 8px; }
  nav { grid-column: 1 / -1; gap: 24px; }
  .intro { padding-block: 44px; }
  h1 { letter-spacing: -1.8px; font-size: clamp(2.6rem, 8.5vw, 3.5rem); }
  .lead { font-size: 1rem; }
  summary { grid-template-columns: 28px 1fr 18px; gap: 13px; padding-block: 21px; }
  .week-title { font-size: 1rem; }
  .date { display: none; }
  .entry { padding: 0 0 22px 41px; }
  .photo-grid { grid-template-columns: 1fr; gap: 18px; }
  .project { display: block; padding: 25px; }
  .project p { margin-top: 18px; }
}
@media (max-width: 360px) {
  nav { width: 100%; justify-content: space-between; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .toggle { transition: none; }
}
@media print {
  nav, .skip { display: none; }
  .wrap { width: 100%; }
  .intro { padding-block: 24px; }
}

/* Multi-page notebook, September 2026. */
.week-link { display: grid; grid-template-columns: 45px 1fr 75px 20px; gap: 20px; align-items: baseline; border-top: 1px solid var(--line); padding-block: 24px; text-decoration: none; }
.week-link:last-child { border-bottom: 1px solid var(--line); }
.week-link:hover .week-title { text-decoration: underline; }
.notebook { padding-top: 32px; }
.back { font-size: .875rem; color: var(--muted); }
.page-title { padding: 26px 0 32px; border-bottom: 1px solid var(--line); }
.page-title h1 { max-width: 18ch; }
.status { color: var(--muted); margin-bottom: 0; }
.notebook article { max-width: 780px; }
.notebook article > section { margin-block: 38px; }
.notebook article p, .notebook dd { color: var(--muted); }
.notebook h3 { font-size: 1rem; margin-top: 28px; }
.notebook dt { margin-top: 18px; font-weight: 600; }
.notebook dd { margin: 6px 0 0; }
pre { padding: 18px; background: #e9eddf; overflow-x: auto; font-size: .85rem; }
code { overflow-wrap: anywhere; }
.page-nav { border-top: 1px solid var(--line); padding-top: 24px; justify-content: space-between; flex-wrap: wrap; }
@media (max-width: 640px) { .week-link { grid-template-columns: 28px 1fr 18px; gap: 13px; } .page-title h1 { font-size: 2.6rem; overflow-wrap: anywhere; } }

/* Week 01 CAD comparison. */
.table-scroll { overflow-x: auto; margin-block: 22px; }
.cad-table { width: 100%; border-collapse: collapse; font-size: .875rem; }
.cad-table caption { text-align: left; margin-bottom: 12px; color: var(--muted); }
.cad-table th, .cad-table td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); }
.cad-table thead { background: #e9eddf; }

.notebook article details > summary { display: block; padding: 14px 0; border-block: 1px solid var(--line); font-weight: 600; }
.notebook article details > summary::before { content: '+ '; font-family: var(--mono); }
.notebook article details[open] > summary::before { content: '− '; }