@font-face { font-family: 'Greed'; src: url('/fonts/GreedStandard-Regular.woff2') format('woff2');
             font-weight: 400; font-style: normal; font-display: swap; }
@font-face { font-family: 'Greed'; src: url('/fonts/GreedStandard-RegularItalic.woff2') format('woff2');
             font-weight: 400; font-style: italic; font-display: swap; }
@font-face { font-family: 'Greed'; src: url('/fonts/GreedStandard-Medium.woff2') format('woff2');
             font-weight: 500; font-style: normal; font-display: swap; }
@font-face { font-family: 'Greed'; src: url('/fonts/GreedStandard-SemiBold.woff2') format('woff2');
             font-weight: 600; font-style: normal; font-display: swap; }
@font-face { font-family: 'Greed Wide'; src: url('/fonts/GreedWide-SemiBold.woff2') format('woff2');
             font-weight: 600; font-style: normal; font-display: swap; }

:root {
  --paper: #FBF9F4; --ink: #16213A; --blue: #2C4E87; --blue-deep: #223E6C;
  --muted: #6A7280; --body: #414B5E; --card: #FFFFFF; --hairline: rgba(22, 33, 58, .1);
}
* { box-sizing: border-box; margin: 0; }
body {
  background: radial-gradient(900px 480px at 78% -140px, rgba(44, 78, 135, .06), transparent 68%), var(--paper);
  color: var(--ink);
  font: 400 1.05rem/1.7 'Greed', Georgia, 'Times New Roman', serif;
  -webkit-font-smoothing: antialiased;
}
.wrap { max-width: 760px; margin: 0 auto; padding: 0 24px; }
header { padding: 26px 0 0; }
.bar { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.wordmark { font-family: 'Greed Wide', 'Greed', Georgia, serif; font-weight: 600;
            font-size: 1.25rem; color: var(--ink); text-decoration: none; }
nav a { color: var(--muted); text-decoration: none; margin-left: 20px; font-size: .93rem; }
nav a:hover { color: var(--blue); }

main { padding: 44px 0 40px; }
.crumbs { font-size: .9rem; color: var(--muted); margin-bottom: 20px; }
.crumbs a { color: var(--blue); text-decoration: none; }
h1 { font-weight: 600; font-size: clamp(1.9rem, 4.5vw, 2.7rem); line-height: 1.12;
     letter-spacing: -.01em; margin-bottom: 18px; }
h2 { font-weight: 600; font-size: 1.35rem; margin: 0 0 14px; }
.lede { font-size: 1.1rem; color: var(--body); max-width: 58ch; }
.meta { margin-top: 12px; color: var(--muted); font-size: .95rem; font-style: italic; }

.problems { margin-top: 40px; display: flex; flex-direction: column; gap: 18px; }
.problem { background: var(--card); border: 1px solid var(--hairline); border-radius: 16px;
           padding: 22px 24px; box-shadow: 0 14px 36px -26px rgba(22, 33, 58, .3); }
.phead { display: flex; align-items: baseline; gap: 10px; margin-bottom: 8px; }
.pnum { font-style: italic; color: var(--blue); font-size: 1.15rem; font-weight: 500; }
.chip { font-size: .74rem; font-weight: 500; letter-spacing: .05em; color: var(--blue);
        border: 1px solid rgba(44, 78, 135, .28); border-radius: 999px; padding: 2px 10px;
        background: rgba(44, 78, 135, .05); }
.statement { color: var(--ink); }
details { margin-top: 14px; }
summary { cursor: pointer; color: var(--blue); font-weight: 500; font-size: .97rem;
          list-style-position: inside; }
summary:hover { color: var(--blue-deep); }
.answer { border-top: 1px solid var(--hairline); margin-top: 12px; padding-top: 14px;
          color: var(--body); font-size: .99rem; }
.answer .final { color: var(--ink); font-weight: 500; margin-bottom: 8px; }
.answer p { margin: 8px 0; }
.math-block { margin: 10px 0; padding: 4px 0; overflow-x: auto; }
.katex { font-size: 1.06em; }

.cta { margin: 52px 0 8px; background: var(--card); border: 1px solid var(--hairline);
       border-radius: 18px; padding: 28px; box-shadow: 0 18px 44px -30px rgba(22, 33, 58, .32); }
.cta-line { color: var(--body); max-width: 52ch; }
.waitlist { margin-top: 18px; max-width: 460px; }
.waitlist form { display: flex; gap: 10px; }
.waitlist input { flex: 1; font: inherit; font-size: .98rem; color: var(--ink);
  background: var(--paper); border: 1px solid var(--hairline); border-radius: 999px;
  padding: 12px 20px; outline: none; min-width: 0; }
.waitlist input:focus { border-color: rgba(44, 78, 135, .5); }
.waitlist button { font: inherit; font-weight: 500; font-size: .98rem; color: #fff;
  background: var(--blue); border: 0; border-radius: 999px; padding: 12px 24px; cursor: pointer; }
.waitlist button:hover { background: var(--blue-deep); }
.waitlist button:disabled { opacity: .6; cursor: default; }
.waitlist .note { margin-top: 10px; font-size: .9rem; color: var(--muted); font-style: italic; }
.waitlist .ok { color: var(--blue); font-style: normal; font-weight: 500; }
@media (max-width: 560px) { .waitlist form { flex-direction: column; } .waitlist button { width: 100%; } }

.more { margin-top: 48px; }
.linklist, .hublist { list-style: none; padding: 0; }
.linklist li { margin: 8px 0; }
.linklist a, .hublist a { color: var(--blue); text-decoration: none; }
.linklist a:hover, .hublist a:hover { text-decoration: underline; }
.hublist { margin-top: 30px; display: flex; flex-direction: column; gap: 4px; }
.hublist li { display: flex; justify-content: space-between; align-items: baseline; gap: 14px;
              padding: 13px 4px; border-bottom: 1px solid var(--hairline); }
.hublist .count { color: var(--muted); font-size: .9rem; font-style: italic; white-space: nowrap; }

footer { border-top: 1px solid var(--hairline); padding: 34px 0 54px; font-size: .93rem;
         color: var(--muted); margin-top: 60px; }
footer .cols { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
footer a { color: var(--blue); text-decoration: none; }
footer a:hover { text-decoration: underline; }
footer .legal { margin-top: 12px; font-size: .86rem; }
.inkline { color: var(--ink); }