:root {
  --iu-crimson: #990000;
  --iu-crimson-dark: #710000;
  --ink: #171a20;
  --muted: #626a76;
  --line: #e4e6ea;
  --paper: #ffffff;
  --wash: #f6f5f2;
  --student: #1261a0;
  --shadow: 0 18px 45px rgba(21, 24, 31, .08);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Outfit", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 17px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; }
.skip-link {
  position: fixed; top: 10px; left: 10px; z-index: 1000; padding: 10px 14px;
  color: #fff; background: var(--iu-crimson); border-radius: 7px; transform: translateY(-150%);
}
.skip-link:focus { transform: translateY(0); }
:focus-visible { outline: 3px solid #e8b44f; outline-offset: 3px; }
.site-header {
  position: sticky; top: 0; z-index: 100; border-bottom: 1px solid rgba(228, 230, 234, .9);
  background: rgba(255, 255, 255, .92); backdrop-filter: blur(18px);
}
.nav-shell {
  width: min(1180px, calc(100% - 40px)); min-height: 72px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between; gap: 28px;
}
.site-brand {
  display: flex; align-items: center; gap: 18px; font-weight: 800;
  letter-spacing: -.02em; text-decoration: none;
}
.site-brand img { width: auto; height: 40px; }
nav { display: flex; gap: 28px; }
nav a { color: #3f4651; font-size: .9rem; font-weight: 600; text-decoration: none; }
nav a:hover { color: var(--iu-crimson); }
.hero {
  overflow: hidden; border-bottom: 1px solid var(--line);
  background: radial-gradient(circle at 78% 20%, rgba(153, 0, 0, .10), transparent 27rem),
    linear-gradient(135deg, #fff 0%, #fff 58%, #f8f4f2 100%);
}
.hero-grid {
  width: min(1180px, calc(100% - 40px)); min-height: 510px; margin: 0 auto; padding: 84px 0 76px;
  display: grid; grid-template-columns: 1.08fr .92fr; align-items: center; gap: 90px;
}
.eyebrow { color: var(--iu-crimson); font-size: .76rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.course-code {
  margin: 18px 0 -4px; color: var(--iu-crimson); font-size: clamp(3rem, 7vw, 5.4rem);
  font-weight: 800; letter-spacing: -.07em; line-height: 1;
}
h1 { margin: 0; font-size: clamp(2.7rem, 6vw, 5.2rem); font-weight: 800; letter-spacing: -.06em; line-height: .98; }
.hero-copy { max-width: 670px; margin: 28px 0 0; color: var(--muted); font-size: 1.15rem; line-height: 1.65; }
.hero-actions { margin-top: 34px; display: flex; flex-wrap: wrap; gap: 12px; }
.button {
  display: inline-flex; min-height: 48px; padding: 0 22px; align-items: center; justify-content: center;
  border: 1px solid var(--ink); border-radius: 999px; font-weight: 700; text-decoration: none;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.button:hover { transform: translateY(-2px); }
.button-primary { color: #fff; background: var(--ink); box-shadow: 0 8px 22px rgba(17, 24, 39, .16); }
.button-primary:hover { background: var(--iu-crimson); border-color: var(--iu-crimson); }
.button-secondary { border-color: var(--line); background: #fff; }
.process-card {
  padding: 32px; display: grid; grid-template-columns: 1fr auto 1fr auto 1fr;
  align-items: center; gap: 12px; border: 1px solid rgba(153, 0, 0, .12); border-radius: 24px;
  background: rgba(255, 255, 255, .9); box-shadow: var(--shadow);
}
.process-step { text-align: center; }
.process-step span {
  width: 40px; height: 40px; margin: 0 auto 14px; display: grid; place-items: center;
  border-radius: 50%; color: #fff; background: var(--iu-crimson); font-size: .76rem; font-weight: 800;
}
.process-step strong, .process-step small { display: block; }
.process-step strong { font-size: 1.05rem; }
.process-step small { margin-top: 5px; color: var(--muted); font-size: .78rem; line-height: 1.3; }
.process-arrow { color: #a4aab3; font-size: 1.3rem; }
.catalog { width: min(1040px, calc(100% - 40px)); margin: 0 auto; padding: 76px 0 90px; }
.catalog-heading { display: flex; align-items: end; justify-content: space-between; gap: 40px; }
h2 { margin: 8px 0 4px; font-size: clamp(2rem, 4vw, 3.15rem); letter-spacing: -.045em; line-height: 1.1; }
.catalog-heading p { margin: 10px 0 0; color: var(--muted); }
.search {
  width: min(330px, 100%); min-width: 270px; height: 50px; padding: 0 16px;
  display: flex; align-items: center; gap: 10px; border: 1px solid var(--line);
  border-radius: 12px; background: #fff; box-shadow: 0 5px 16px rgba(21, 24, 31, .04);
}
.search:focus-within { border-color: rgba(153, 0, 0, .55); box-shadow: 0 0 0 4px rgba(153, 0, 0, .08); }
.search svg { width: 20px; fill: none; stroke: #777f8a; stroke-width: 2; }
.search input { width: 100%; height: 100%; border: 0; outline: 0; color: var(--ink); background: transparent; font: inherit; }
.legend { margin: 30px 0 18px; display: flex; justify-content: flex-end; gap: 22px; color: var(--muted); font-size: .82rem; }
.legend span { display: inline-flex; align-items: center; gap: 7px; }
.dot { width: 8px; height: 8px; display: inline-block; border-radius: 50%; }
.dot-student { background: var(--student); }
.dot-instructor { background: var(--iu-crimson); }
.lecture-grid { border-top: 1px solid var(--line); }
.lecture-card {
  min-height: 102px; padding: 20px 4px; display: grid; grid-template-columns: 64px 1fr auto;
  align-items: center; gap: 22px; border-bottom: 1px solid var(--line); transition: background .18s ease, padding .18s ease;
}
.lecture-card:hover { padding-left: 14px; padding-right: 14px; background: #fafafa; }
.lecture-number { color: var(--iu-crimson); font-size: 1.15rem; font-weight: 800; font-variant-numeric: tabular-nums; }
.phase { color: var(--muted); font-size: .69rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.lecture-copy h3 { margin: 4px 0 0; font-size: 1.08rem; letter-spacing: -.015em; line-height: 1.3; }
.lecture-links { display: flex; gap: 9px; }
.lecture-links a {
  min-width: 96px; padding: 9px 14px; border: 1px solid currentColor; border-radius: 999px;
  font-size: .82rem; font-weight: 700; text-align: center; text-decoration: none;
  transition: color .16s ease, background .16s ease, transform .16s ease;
}
.lecture-links a:hover { transform: translateY(-1px); color: #fff; }
.lecture-links .student { color: var(--student); }
.lecture-links .student:hover { background: var(--student); }
.lecture-links .instructor { color: var(--iu-crimson); }
.lecture-links .instructor:hover { background: var(--iu-crimson); }
.lecture-card[hidden] { display: none; }
.empty-state { padding: 48px 0; color: var(--muted); text-align: center; }
footer {
  min-height: 130px; padding: 30px max(20px, calc((100vw - 1180px) / 2)); display: flex;
  align-items: center; justify-content: space-between; gap: 24px; color: #fff; background: var(--ink);
}
footer strong, footer span { display: block; }
footer span { margin-top: 4px; color: #b9bec7; font-size: .86rem; }
footer a { color: #fff; font-weight: 600; text-decoration-thickness: 1px; text-underline-offset: 4px; }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}
@media (max-width: 900px) {
  .hero-grid { min-height: auto; grid-template-columns: 1fr; gap: 50px; padding: 64px 0; }
  .process-card { max-width: 640px; }
  .catalog-heading { align-items: stretch; flex-direction: column; gap: 26px; }
  .search { width: 100%; }
}
@media (max-width: 680px) {
  .nav-shell { width: min(100% - 28px, 1180px); }
  .site-brand span { display: none; }
  .site-brand img { height: 34px; }
  nav { gap: 16px; }
  nav a { font-size: .8rem; }
  .hero-grid, .catalog { width: min(100% - 30px, 1180px); }
  .hero-grid { padding: 50px 0; }
  .process-card { padding: 24px 14px; gap: 6px; }
  .process-step small { display: none; }
  .process-arrow { font-size: 1rem; }
  .lecture-card { grid-template-columns: 40px 1fr; gap: 10px 14px; padding: 20px 0; }
  .lecture-links { grid-column: 2; flex-wrap: wrap; }
  .lecture-links a { min-width: 104px; }
  .legend { justify-content: flex-start; }
  footer { align-items: flex-start; flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; }
}