*{box-sizing:border-box}
:root{--ink:#111827;--muted:#5b6472;--line:#e6e2d9;--paper:#f7f5f0;--card:#fff;--saffron:#ea580c;--saffron-soft:#fff7ed;--navy:#1e3a5f;--deep:#0f2440;--teal:#0f766e;--mint:#ecfdf5;--good:#15803d;--bad:#b91c1c}
html{-webkit-text-size-adjust:100%}
body{font-family:system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;margin:0;color:var(--ink);line-height:1.65;background:var(--paper);font-size:17px}
a{color:var(--navy)}
a:hover{color:var(--saffron)}
img{max-width:100%;height:auto}
h1,h2,h3{font-family:Georgia,"Times New Roman",serif;line-height:1.2;color:var(--ink)}
.skip{position:absolute;left:-999px}.skip:focus{left:1rem;top:1rem;background:#fff;padding:.5rem 1rem;z-index:10}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}
.small{font-size:.88rem;color:var(--muted)}
.kicker{font-size:.78rem;text-transform:uppercase;letter-spacing:.12em;color:var(--teal);font-weight:700;margin:0 0 .4rem}
.kicker a{color:inherit;text-decoration:none}.kicker a:hover{text-decoration:underline}
.meta{color:var(--muted);font-size:.88rem}

/* header */
.top{background:#fffdf8;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:5}
.top-inner{max-width:1100px;margin:0 auto;padding:.5rem 1rem;display:flex;align-items:center;gap:1rem;flex-wrap:wrap}
.brand img{display:block;height:48px;width:auto}
.sitenav{display:flex;gap:.25rem;margin-left:auto;flex-wrap:wrap}
.sitenav a{text-decoration:none;color:var(--navy);font-weight:600;font-size:.92rem;padding:.4rem .65rem;border-radius:8px}
.sitenav a:hover,.sitenav a[aria-current]{background:var(--saffron-soft);color:var(--saffron)}
.menu-btn{display:none;margin-left:auto;background:none;border:1px solid var(--line);border-radius:8px;padding:.4rem .8rem;font:inherit;color:var(--navy)}
@media (max-width:820px){
  .menu-btn{display:block}
  .sitenav{display:none;width:100%;flex-direction:column;margin:0 0 .5rem}
  .sitenav.open{display:flex}
  .sitenav a{padding:.6rem .5rem;border-bottom:1px solid var(--line);border-radius:0}
  .brand img{height:40px}
}

main{margin:0 auto;padding:1.5rem 1rem 3rem}
main.narrow{max-width:760px}
main.wide{max-width:1100px}
.crumbs{font-size:.85rem;color:var(--muted);margin-bottom:1rem}
.crumbs a{color:var(--muted)}

/* hero (home) */
.hero{background:linear-gradient(135deg,#0f2440 0%,#1e3a5f 55%,#0f766e 130%);color:#fff;border-radius:22px;padding:3rem 1.5rem;margin:0 0 1.5rem}
.hero-inner{max-width:820px}
.eyebrow{text-transform:uppercase;letter-spacing:.18em;font-size:.75rem;color:#fbbf24;font-weight:700;margin:0 0 .75rem}
.hero h1{color:#fff;font-size:clamp(2.1rem,6vw,3.2rem);line-height:1.05;margin:0 0 .75rem}
.hero p{color:#dbe7f3;font-size:1.12rem;margin:0}
.meta-line{margin-top:1.5rem;display:flex;flex-wrap:wrap;gap:.5rem}
.pill{background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.25);padding:.35rem .8rem;border-radius:999px;font-size:.85rem}
.feature{background:linear-gradient(135deg,#fff7ed,#ecfdf5);border:2px solid #f97316;border-radius:18px;padding:1.5rem;margin-bottom:1.5rem}
.feature h2{margin:.2rem 0 .5rem}
.purpose{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem;margin-bottom:1rem}
.purpose div{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:1.2rem}
.purpose h2{font-size:1.1rem;margin:0 0 .4rem;color:var(--navy)}
.purpose p{margin:0;color:#374151;font-size:.95rem}
@media (max-width:760px){.purpose{grid-template-columns:1fr}.hero{padding:2rem 1.25rem;border-radius:16px}}

.section-title{font-size:1.5rem;margin:2.25rem 0 1rem}
.page-head{margin-bottom:1.5rem}
.page-head h1{font-size:clamp(1.9rem,5vw,2.6rem);margin:.2rem 0 .6rem}
.lede{font-size:1.1rem;color:#374151;max-width:760px}

/* cards & grids */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:1.2rem;box-shadow:0 6px 18px rgba(15,36,64,.05)}
.card h3{font-size:1.15rem;margin:.1rem 0 .5rem}
.card h3 a{text-decoration:none}
.card h3 a:hover{text-decoration:underline}
.card p{margin:.3rem 0}
.theme-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:.85rem}
.theme-card{display:flex;flex-direction:column;gap:.3rem;text-decoration:none;color:var(--ink);transition:transform .15s,border-color .15s}
.theme-card:hover{transform:translateY(-2px);border-color:#f97316;color:var(--ink)}
.theme-card .icon{font-size:1.6rem}
.theme-card strong{font-family:Georgia,serif;font-size:1.1rem}
.theme-list{list-style:none;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:1rem}
.start-list{columns:2;column-gap:2rem;padding-left:1.2rem}
.start-list li{margin:.35rem 0;break-inside:avoid}
.start-list a{text-decoration:none}.start-list a:hover{text-decoration:underline}
.start-list span{color:var(--teal);font-weight:700;font-size:.85rem;margin-right:.3rem}
@media (max-width:640px){.start-list{columns:1}}
.two{display:grid;grid-template-columns:1fr 1fr;gap:1rem}
@media (max-width:700px){.two{grid-template-columns:1fr}}
.spaced{margin-top:2rem}

/* buttons */
.btn{display:inline-block;font:inherit;font-size:.92rem;font-weight:600;padding:.5rem .9rem;border-radius:10px;border:1px solid var(--line);background:#fff;color:var(--navy);text-decoration:none;cursor:pointer;margin:.15rem .1rem}
.btn:hover{border-color:var(--navy);color:var(--navy)}
.btn-primary{background:var(--navy);color:#fff;border-color:var(--navy)}
.btn-primary:hover{background:var(--deep);color:#fff}

/* filters */
.filters{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:1rem;margin-bottom:1rem}
.search input{width:100%;font:inherit;padding:.65rem .9rem;border:1px solid var(--line);border-radius:10px;background:#fff}
.chips{display:flex;flex-wrap:wrap;gap:.4rem;margin-top:.75rem}
.chip{font:inherit;font-size:.85rem;padding:.35rem .7rem;border-radius:999px;border:1px solid var(--line);background:#fff;cursor:pointer;color:var(--ink)}
.chip.active{background:var(--navy);color:#fff;border-color:var(--navy)}

/* note page */
.note h1{font-size:clamp(1.8rem,5vw,2.3rem);margin:.2rem 0 .4rem}
.progress{height:4px;background:var(--line);border-radius:4px;margin:.6rem 0 1.5rem;overflow:hidden}
.progress span{display:block;height:100%;background:linear-gradient(90deg,var(--teal),#f97316)}
.prose p{margin:.9rem 0}
.prose h2{font-size:1.4rem;margin-top:2.2rem;color:var(--navy)}
.prose figure{margin:2rem 0}
.prose figure img{width:100%;border-radius:14px;border:1px solid var(--line);box-shadow:0 12px 28px rgba(15,36,64,.12)}
.prose figcaption,.note figcaption{color:var(--muted);font-size:.88rem;margin-top:.5rem;overflow-wrap:anywhere}
.prose a{overflow-wrap:anywhere}
.pic-note{background:var(--saffron-soft);border:1px solid #fed7aa;border-radius:12px;padding:1rem;font-size:.95rem}
.takeaways{background:#fff;border:1px solid var(--line);border-left:4px solid var(--teal);border-radius:14px;padding:.4rem 1.25rem;margin-top:1.5rem}
.takeaways h2{margin-top:.8rem !important;font-size:1.25rem}
.prose table{width:100%;border-collapse:collapse;margin:1rem 0;font-size:.95rem}
.prose th,.prose td{border:1px solid var(--line);padding:.55rem;text-align:left;vertical-align:top}
.prose th{background:#eef2f7}
.prose blockquote{border-left:4px solid #f97316;padding-left:1rem;color:#374151;font-style:italic;margin-left:0}
.prose hr{border:none;border-top:1px solid var(--line);margin:2rem 0}
.prose .cols{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}
.prose .cols>div{background:#fff;border:1px solid var(--line);border-radius:14px;padding:0 1rem}
@media (max-width:700px){.prose .cols{grid-template-columns:1fr}}
.prose .intro{font-size:1.1rem}
.table-wrap{overflow-x:auto}

.share{display:flex;flex-wrap:wrap;align-items:center;gap:.3rem;margin:2rem 0 1rem;padding:1rem;background:#fff;border:1px solid var(--line);border-radius:14px}
.share-label{font-weight:700;margin-right:.4rem;font-size:.92rem}
.share-native{display:none}
.has-share .share-native{display:inline-block}
.pager{margin:1.5rem 0}
.next-big{display:block;background:var(--navy);color:#fff;text-decoration:none;border-radius:14px;padding:1rem 1.25rem}
.next-big:hover{background:var(--deep);color:#fff}
.next-big span{display:block;font-size:.8rem;text-transform:uppercase;letter-spacing:.12em;color:#fbbf24;font-weight:700}
.next-big strong{font-family:Georgia,serif;font-size:1.15rem}
.pager-row{display:flex;flex-wrap:wrap;gap:1rem;margin-top:.75rem;font-size:.92rem}
.related ul{padding-left:1.2rem}
.related h2{font-size:1.2rem}
.signup{background:linear-gradient(135deg,#fff7ed,#ecfdf5);border:1px solid #fed7aa;border-radius:16px;padding:1.25rem 1.4rem;margin-top:2.5rem}
.signup h2{margin:.1rem 0 .4rem;font-size:1.3rem}
.signup p{margin:.4rem 0}

/* quiz */
.quiz{padding-left:0;list-style:none}
.q{background:#fff;border:1px solid var(--line);border-radius:14px;padding:1rem 1.2rem;margin-bottom:1rem}
.q-text{margin:.2rem 0 .7rem}
.opts{list-style:none;padding:0;margin:0;display:grid;gap:.4rem}
.opt{width:100%;text-align:left;font:inherit;padding:.6rem .8rem;border:1px solid var(--line);border-radius:10px;background:#fafaf7;cursor:pointer;color:var(--ink)}
.opt:hover:not([disabled]){border-color:var(--navy)}
.opt.right{background:#dcfce7;border-color:var(--good)}
.opt.wrong{background:#fee2e2;border-color:var(--bad)}
.opt[disabled]{cursor:default}
.explain{margin:.7rem 0 0;font-size:.95rem;color:#374151}
.quiz-score{background:#fff;border:2px solid var(--teal);border-radius:14px;padding:1rem 1.2rem}

/* glossary & syllabus */
.az a{display:inline-block;padding:.15rem .45rem;text-decoration:none;font-weight:700}
.glossary{margin:0}
.letter{font-size:1.6rem;border-bottom:1px solid var(--line);padding-bottom:.2rem;margin-top:2rem}
.term{padding:.6rem 0;border-bottom:1px dashed var(--line)}
.term dt{font-weight:700;font-family:Georgia,serif;font-size:1.08rem}
.term dd{margin:.2rem 0 0}
.term:target{background:var(--saffron-soft)}
.syllabus{width:100%;border-collapse:collapse;background:#fff;border-radius:14px;overflow:hidden;font-size:.95rem}
.syllabus th,.syllabus td{border:1px solid var(--line);padding:.6rem .75rem;vertical-align:top;text-align:left}
.syllabus thead th{background:var(--navy);color:#fff}
.syllabus tbody th{width:38%;font-weight:600}
.syllabus ul{margin:0;padding-left:1.1rem}
@media (max-width:640px){.syllabus,.syllabus tbody,.syllabus tr,.syllabus th,.syllabus td{display:block;width:100%}.syllabus thead{display:none}.syllabus tbody th{background:#eef2f7;width:100%}}

.foot{border-top:1px solid var(--line);background:#fffdf8}
.foot-inner{max-width:1100px;margin:0 auto;padding:1.5rem 1rem;display:grid;gap:.6rem;font-size:.92rem}
.foot-links{display:flex;flex-wrap:wrap;gap:.9rem}

@media print{.top,.foot,.share,.signup,.pager,.related{display:none}body{background:#fff}}