/* KD/TF Biomechanics review — styled after the Colorlib "Tutor" template */
:root{
  --primary:#0779e4; --primary-dark:#0561b8; --ink:#1a1a1a; --text:#555; --muted:#a6a6a6;
  --bg:#f8f9fa; --white:#fff; --line:#e9e9e9; --grf:#e4572e; --good:#1f9d63; --bad:#d64541; --warn:#e0a100;
  --shadow:0 10px 30px rgba(0,0,0,.08);
  --font:"Raleway",-apple-system,"Segoe UI",Arial,sans-serif; --mono:"IBM Plex Mono",Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:70px}
body{margin:0;font-family:var(--font);color:var(--text);background:var(--white);font-size:16px;line-height:1.7}
img{max-width:100%;display:block}
a{color:var(--primary);text-decoration:none}
a:hover{color:var(--primary-dark)}
h1,h2,h3,h4{color:var(--ink);font-family:var(--font);line-height:1.25;margin:0 0 .5em}
.container{max-width:1140px;margin:0 auto;padding:0 16px}

/* ---------- navbar ---------- */
.site-navbar{position:absolute;top:0;left:0;right:0;z-index:20;padding:22px 0}
.site-navbar.fixed{position:fixed;background:rgba(255,255,255,.97);box-shadow:0 2px 12px rgba(0,0,0,.08);padding:12px 0}
.nav-row{display:flex;align-items:center;justify-content:space-between;gap:16px}
.site-logo{font-size:22px;font-weight:700;color:#fff;letter-spacing:.02em}
.site-logo span{font-weight:400;opacity:.85}
.site-navbar.fixed .site-logo{color:var(--ink)}
.site-menu{display:flex;gap:26px;list-style:none;margin:0;padding:0}
.site-menu a{color:#fff;font-size:15px;font-weight:700;position:relative;padding:4px 0}
.site-menu a:after{content:"";position:absolute;left:0;right:100%;bottom:-2px;height:2px;background:currentColor;transition:right .25s}
.site-menu a:hover:after,.site-menu a.active:after{right:0}
.site-navbar.fixed .site-menu a{color:var(--ink)}
.site-navbar.fixed .site-menu a.active{color:var(--primary)}
.menu-toggle{display:none;background:none;border:0;color:#fff;font-size:28px;cursor:pointer;padding:4px 8px;line-height:1}
.site-navbar.fixed .menu-toggle{color:var(--ink)}
@media (max-width:991px){
  .menu-toggle{display:block}
  .site-menu{display:none;position:absolute;top:100%;left:0;right:0;flex-direction:column;gap:0;background:#fff;box-shadow:var(--shadow);padding:8px 0}
  .site-menu.open{display:flex}
  .site-menu a{color:var(--ink);display:block;padding:10px 20px}
  .site-menu a:after{display:none}
}

/* ---------- hero (site-section-cover) ---------- */
.site-section-cover{position:relative;background-size:cover;background-position:center 35%;min-height:640px;height:calc(100vh - 120px);max-height:780px;display:flex;align-items:center}
.site-section-cover:before{content:"";position:absolute;inset:0;background:rgba(0,0,0,.42)}
.site-section-cover .container{position:relative;z-index:2;text-align:center;width:100%;padding-bottom:120px}
.site-section-cover h1{color:#fff;font-size:clamp(34px,6vw,58px);font-weight:400;line-height:1.1;margin-bottom:14px}
.site-section-cover h1 strong{font-weight:900}
.site-section-cover p{color:#fff;font-size:18px;max-width:640px;margin:0 auto}
.hero-meta{display:inline-block;margin-top:22px;color:#fff;border:1px solid rgba(255,255,255,.5);border-radius:30px;padding:6px 18px;font-size:14px;font-weight:700}
.hero-credit{margin-top:14px;font-size:11px;color:rgba(255,255,255,.75)}
.hero-credit a{color:#fff;text-decoration:underline}
@media (max-width:991px){.site-section-cover{min-height:480px;height:auto;padding:130px 0 60px}.site-section-cover .container{padding-bottom:100px}}

/* ---------- overlap cards ---------- */
.overlap{position:relative;z-index:3;margin-top:-150px}
.feature-row{display:grid;grid-template-columns:1.35fr 1fr;gap:30px}
@media (max-width:991px){.feature-row{grid-template-columns:1fr}}
.post-entry-big{background:#fff;box-shadow:var(--shadow);display:grid;grid-template-columns:1fr 1fr}
.post-entry-big img{width:100%;height:100%;object-fit:cover;min-height:320px}
.post-entry-big .contents{padding:28px}
@media (max-width:640px){.post-entry-big{grid-template-columns:1fr}.post-entry-big img{min-height:220px;max-height:260px}}
.caption{font-size:12px;text-transform:uppercase;font-weight:700;letter-spacing:.2rem;color:var(--primary)}
.post-entry-big h2{font-size:30px;margin:8px 0 14px}
.post-list{background:#fff;box-shadow:var(--shadow);padding:10px 24px}
.post-sm{display:grid;grid-template-columns:96px 1fr;gap:16px;align-items:center;padding:14px 0;border-bottom:1px solid var(--line)}
.post-sm:last-child{border-bottom:0}
.post-sm img{width:96px;height:72px;object-fit:cover}
.post-sm h3{font-size:17px;margin:2px 0 0}
.post-sm h3 a{color:var(--ink)}
.post-sm h3 a:hover{color:var(--primary)}
.btn{display:inline-block;background:var(--primary);color:#fff;border:0;border-radius:30px;padding:10px 26px;font-family:var(--font);font-weight:700;font-size:15px;cursor:pointer;transition:background .2s}
.btn:hover{background:var(--primary-dark);color:#fff}
.btn-outline{background:transparent;color:var(--primary);border:2px solid var(--primary);padding:8px 22px}
.btn-outline:hover{background:var(--primary);color:#fff}

/* ---------- sections ---------- */
.site-section{padding:80px 0}
.site-section.alt{background:var(--bg)}
@media (max-width:991px){.site-section{padding:50px 0}}
.heading{text-align:center;max-width:760px;margin:0 auto 44px}
.heading h2{font-size:34px;font-weight:700;color:var(--primary);margin:6px 0 10px}
.heading p{margin:0}
.split{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:30px;align-items:start}
.split.wide-left{grid-template-columns:minmax(0,1.1fr) minmax(0,.9fr)}
@media (max-width:860px){.split,.split.wide-left{grid-template-columns:1fr}}
.panel{background:#fff;box-shadow:var(--shadow);padding:26px}
.panel h3{font-size:20px}

/* figures with citation */
figure{margin:0;background:#fff;box-shadow:var(--shadow)}
figure img{width:100%;height:auto;max-height:400px;object-fit:contain;background:#f7f7f7}
figure.cover img{height:280px;object-fit:cover}
figcaption{padding:12px 16px 14px;font-size:14px;color:var(--text);line-height:1.5}
figcaption .cite{display:block;margin-top:4px;font-size:12px;color:var(--muted)}
figcaption .cite a{color:var(--muted);text-decoration:underline}
.fig-row{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-bottom:34px}
@media (max-width:640px){.fig-row{grid-template-columns:1fr}}

/* flashcards */
.cards{display:grid;gap:22px;grid-template-columns:repeat(auto-fill,minmax(200px,1fr))}
.card{perspective:1000px;height:220px;cursor:pointer;background:none;border:0;padding:0;text-align:left;font:inherit;color:inherit}
.card .in{position:relative;width:100%;height:100%;transition:transform .5s;transform-style:preserve-3d}
.card.flip .in{transform:rotateY(180deg)}
.card .face{position:absolute;inset:0;backface-visibility:hidden;padding:22px;display:flex;flex-direction:column;gap:8px;box-shadow:var(--shadow)}
.card .front{background:#fff;border-top:4px solid var(--primary)}
.card .back{background:var(--primary);color:#fff;transform:rotateY(180deg);font-size:15px;line-height:1.55}
.card .back .caption{color:rgba(255,255,255,.8)}
.card .q{font-size:19px;font-weight:700;color:var(--ink);line-height:1.3}
.card .hint{margin-top:auto;font-size:13px;color:var(--muted)}
.card .back .hint{color:rgba(255,255,255,.75)}
.card:focus-visible{outline:3px solid var(--grf);outline-offset:4px}

/* controls + readouts */
.ctl{display:grid;gap:16px}
.ctl label{display:grid;grid-template-columns:1fr auto;gap:4px 10px;align-items:center;font-size:15px;color:var(--ink);font-weight:700}
.ctl .v{font-family:var(--mono);font-size:14px;color:var(--primary);font-weight:500}
.ctl input[type=range]{grid-column:1/-1;width:100%;accent-color:var(--primary)}
.readout{display:grid;gap:12px;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));margin-top:18px}
.big{background:var(--bg);padding:14px;border-left:3px solid var(--primary)}
.big .k{font-size:11px;text-transform:uppercase;letter-spacing:.15em;font-weight:700;color:var(--muted)}
.big .n{font-family:var(--mono);font-size:24px;color:var(--ink)}
.pill{display:inline-block;font-weight:700;padding:3px 12px;border-radius:30px;font-size:13px;color:#fff;margin-right:4px}
.pill.good{background:var(--good)}.pill.bad{background:var(--bad)}.pill.warn{background:var(--warn);color:#1a1a1a}
.eq{font-family:var(--mono);background:var(--ink);color:#fff;padding:10px 18px;display:inline-block;margin:0 0 18px;font-size:16px}
svg.model{width:100%;height:auto;display:block;background:var(--bg)}
.note{font-size:13px;color:var(--muted);margin-top:12px;line-height:1.5}
.msg{margin:14px 0 0;font-size:15px}

/* quiz */
.quiz{display:grid;gap:18px;max-width:820px;margin:0 auto}
.qq{background:#fff;box-shadow:var(--shadow);padding:22px}
.qq h3{font-size:18px;margin:0 0 12px}
.opts{display:grid;gap:8px}
.opts button{text-align:left;font:inherit;font-size:15px;background:var(--bg);border:1px solid var(--line);color:var(--ink);padding:10px 14px;cursor:pointer;transition:border-color .2s}
.opts button:hover{border-color:var(--primary)}
.opts button.right{border-color:var(--good);background:#e6f6ee}
.opts button.wrong{border-color:var(--bad);background:#fbeaea}
.fb{margin-top:12px;font-size:15px}
.score{position:sticky;top:62px;z-index:5;background:var(--primary);color:#fff;font-weight:700;font-size:18px;padding:10px 20px;max-width:820px;margin:0 auto 18px;display:flex;justify-content:space-between;align-items:center;gap:10px}
.score .btn{background:#fff;color:var(--primary);padding:6px 16px;font-size:13px}

/* readings + credits */
.readings{display:grid;gap:22px;grid-template-columns:repeat(auto-fill,minmax(300px,1fr))}
.reading{background:#fff;box-shadow:var(--shadow);padding:24px;border-top:4px solid var(--primary)}
.reading h3{font-size:17px;margin:6px 0 8px}
.reading p{font-size:14px;margin:0 0 8px}
.reading .ref{font-size:13px;color:var(--muted)}
.credits{font-size:13px;line-height:1.6;columns:2 360px;column-gap:40px;padding-left:18px}
.credits li{break-inside:avoid;margin-bottom:6px}

footer.site-footer{background:#1a1a1a;color:#aaa;padding:50px 0 30px;font-size:14px}
footer.site-footer h3{color:#fff;font-size:17px}
footer.site-footer a{color:#fff}
.foot-row{display:grid;grid-template-columns:2fr 1fr;gap:30px}
@media (max-width:760px){.foot-row{grid-template-columns:1fr}}
.copy{border-top:1px solid #333;margin-top:30px;padding-top:20px;font-size:12px}

/* reveal on scroll (Tutor uses AOS) */
.reveal{opacity:0;transform:translateY(24px);transition:opacity .6s,transform .6s}
.reveal.in-view{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1;transform:none;transition:none}.card .in{transition:none}html{scroll-behavior:auto}}