/* Member site. Audience: retired professionals, many with reduced vision or hearing, on phones.
   Large type and high contrast, in a plain university register: serif headings, thin rules,
   restrained buttons. One column. No motion. */
:root {
  --ink: #161616;
  --paper: #fdfcf9;
  --muted: #5b5b5b;
  --accent: #1f4e8c;
  --line: #cfcbc2;
  --soft: #f2efe8;
  --err-bg: #f7e6e6;
  --err: #7a1d1d;
  --info-bg: #e9eff7;
  --focus: #e0a800;
  --serif: Georgia, "Times New Roman", Times, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
html { font-size: 21px; }
@media (max-width: 480px) { html { font-size: 19px; } }
html.bigger { font-size: 26px; }
[hidden] { display: none !important; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
}
main { max-width: 40rem; margin: 0 auto; padding: 0.5rem 1.2rem 4rem; }
h1, h2 { font-family: var(--serif); font-weight: 400; letter-spacing: -0.01em; }
h1 { font-size: 2.1rem; line-height: 1.15; margin: 0.6rem 0 0.4rem; }
h2 { font-size: 1.45rem; line-height: 1.2; margin: 2rem 0 0.5rem; }
p { margin: 0.6rem 0; }
.lead { font-size: 1.1rem; }
ul { padding-left: 1.2rem; }
li { margin: 0.35rem 0; }
a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
.muted { color: var(--muted); }
.full { width: 100%; }

.topbar { display: flex; justify-content: space-between; align-items: center; gap: 1rem; padding: 0.7rem 0 0.2rem; border-bottom: 1px solid var(--line); }
.topbar a, .topbar span { font-size: 0.9rem; }

.weeks { list-style: none; padding: 0; margin: 0; border-top: 1px solid var(--line); }
.weeks a {
  display: block;
  border-bottom: 1px solid var(--line);
  padding: 0.9rem 0.2rem;
  text-decoration: none;
  color: var(--ink);
}
.weeks a:active { background: var(--soft); }
.weeks .when { display: block; font-size: 0.85rem; color: var(--muted); }
.weeks .name { display: block; font-family: var(--serif); font-size: 1.35rem; }
.weeks .now { border-left: 4px solid var(--accent); padding-left: 0.8rem; }
.weeks .now .when::before { content: "This week \00a0\00b7\00a0 "; color: var(--accent); font-weight: 600; }
.weeks .past .name { color: var(--muted); }

button, a.btn {
  font: inherit;
  font-size: 1rem;
  font-weight: 600;
  min-height: 2.8rem;
  padding: 0.45rem 1.1rem;
  border-radius: 6px;
  border: 2px solid var(--accent);
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
  box-sizing: border-box;
}
button.secondary { background: transparent; color: var(--accent); }
button.small { font-size: 0.85rem; min-height: 2.2rem; padding: 0.15rem 0.7rem; }
button:disabled { opacity: 0.45; cursor: default; }
button:focus-visible, a:focus-visible, input:focus-visible, textarea:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

label { display: block; font-weight: 600; margin: 1.1rem 0 0.3rem; }
input, textarea {
  font: inherit;
  width: 100%;
  box-sizing: border-box;
  padding: 0.55rem 0.7rem;
  border: 2px solid #8a8a8a;
  border-radius: 6px;
  background: #fff;
  color: var(--ink);
}
textarea { min-height: 5.5rem; resize: vertical; }
.row { display: flex; flex-wrap: wrap; gap: 0.6rem; margin: 0.8rem 0; align-items: center; }

.try { border-top: 3px solid var(--accent); padding: 0.2rem 0 1rem; margin: 2rem 0; }
.try h2 { margin-top: 0.8rem; }
.you, .reply { padding: 0.7rem 0 0.7rem 1rem; margin: 1rem 0; white-space: pre-wrap; overflow-wrap: anywhere; border-left: 3px solid var(--line); }
.you { color: var(--muted); }
.reply { border-left-color: var(--accent); min-height: 2rem; }
.you::before, .reply::before { display: block; font-size: 0.8rem; color: var(--muted); font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; margin-bottom: 0.2rem; }
.you::before { content: "Request"; }
.reply::before { content: "Reply"; }
.msg { padding: 0.7rem 0.9rem; border-radius: 6px; margin: 0.8rem 0; }
.msg.err { background: var(--err-bg); color: var(--err); }
.msg.info { background: var(--info-bg); color: var(--accent); }

.slide { padding: 0.4rem 0 0.8rem; margin: 0.4rem 0 1rem; }
.slide h1 { font-size: 2rem; margin: 0.2rem 0 0.5rem; }
.slide .sub { color: var(--accent); font-weight: 600; font-size: 0.95rem; margin: 0.2rem 0 0; }
.slide .lines { font-size: 1.2rem; padding-left: 1.2rem; }
.slide .lines li { margin: 0.6rem 0; }
.slide .demo { border-left: 3px solid var(--accent); padding: 0.4rem 0 0.4rem 0.9rem; color: var(--accent); }
.slide .note { border-left: 3px solid var(--line); padding: 0.4rem 0 0.4rem 0.9rem; font-size: 0.95rem; color: var(--muted); }
.slide .note strong { color: var(--ink); }
.slide .small { color: var(--muted); margin: 0.2rem 0 0.6rem; }
.slide .caption { color: var(--muted); font-size: 0.95rem; margin: 0.6rem 0 0; }
.slide .hero, .slide .media { display: block; width: 100%; height: auto; margin: 0.8rem 0; border-radius: 4px; background: #000; }
.slide .grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.8rem; margin: 0.8rem 0; }
@media (min-width: 640px) { .slide .grid { grid-template-columns: repeat(3, 1fr); } }
.slide .cell img { width: 100%; height: auto; aspect-ratio: 16 / 9; object-fit: cover; border-radius: 4px; display: block; }
.slide .cell .ct { font-family: var(--serif); font-size: 1.1rem; margin-top: 0.3rem; }
.slide .cell .cd { font-size: 0.85rem; color: var(--muted); }
.slide .bignum { font-family: var(--serif); font-size: 4rem; line-height: 1; margin: 0.6rem 0 0.2rem; color: var(--accent); }
.slide .bigt { font-family: var(--serif); font-size: 1.5rem; margin-bottom: 0.6rem; }
.slide blockquote { font-family: var(--serif); font-size: 1.5rem; line-height: 1.3; margin: 1rem 0; padding-left: 1rem; border-left: 3px solid var(--accent); }
.slide blockquote footer { font-family: var(--sans); font-size: 0.85rem; color: var(--muted); margin-top: 0.5rem; border: 0; padding: 0; }
.slide .cols { display: grid; gap: 1rem; margin: 0.8rem 0; }
@media (min-width: 640px) { .slide .cols2 { grid-template-columns: 1fr 1fr; } .slide .cols3 { grid-template-columns: 1fr 1fr 1fr; } }
.slide .col h3 { font-family: var(--serif); font-weight: 400; font-size: 1.15rem; margin: 0 0 0.3rem; color: var(--accent); }
.slide .col .lines { font-size: 1rem; }
.slide .coltext { white-space: pre-wrap; font-size: 0.95rem; margin: 0; }
.slide .timeline { list-style: none; padding: 0; margin: 0.8rem 0; border-left: 3px solid var(--line); }
.slide .timeline li { display: grid; grid-template-columns: 6rem 1fr; gap: 0.6rem; padding: 0.35rem 0 0.35rem 0.8rem; }
.slide .timeline .y { font-weight: 700; color: var(--accent); }
.slide .diagram svg { width: 100%; height: auto; display: block; margin: 0.8rem 0; }
.slide .split .side { display: block; width: 100%; height: auto; margin: 0.8rem 0 0.4rem; border-radius: 4px; }
.viewer { padding-bottom: 6rem; }
#pos { margin: 0.8rem 0 0; font-size: 0.9rem; }
.slidenav {
  position: fixed; left: 0; right: 0; bottom: 0;
  display: flex; gap: 0.6rem; padding: 0.6rem 1.2rem;
  background: var(--paper); border-top: 1px solid var(--line);
}
.slidenav button { flex: 1; min-height: 3.2rem; font-size: 1.1rem; }

footer { margin-top: 3rem; padding-top: 1rem; border-top: 1px solid var(--line); font-size: 0.85rem; color: var(--muted); }
@media (prefers-reduced-motion: no-preference) { html { scroll-behavior: smooth; } }