/* ===== Premium layer: depth, motion, micro-interactions ===== */
html{scroll-behavior:auto}
::selection{background:rgba(41,100,253,.18)}
body{text-rendering:optimizeLegibility}
h1,h2,h3{font-feature-settings:"ss01","cv11"}
.num,.hstats b,.kpi b,.kpi3 b{font-variant-numeric:tabular-nums}

/* header: glass on scroll + reading progress */
.top{transition:box-shadow .25s ease,background-color .25s ease}
body.scrolled .top{background:rgba(20,40,67,.86);-webkit-backdrop-filter:saturate(160%) blur(14px);backdrop-filter:saturate(160%) blur(14px);box-shadow:0 10px 30px -18px rgba(8,18,34,.8)}
#readbar{position:fixed;left:0;top:0;height:3px;width:100%;transform-origin:0 50%;transform:scaleX(0);background-image:linear-gradient(90deg,#2964fd,#6f6bf2,#ee7878);z-index:80;pointer-events:none;transition:opacity .3s}
.theme-btn{display:inline-flex;align-items:center;justify-content:center;width:36px;height:36px;padding:0!important;border-radius:10px!important;transition:background .2s,border-color .2s,transform .2s}
.theme-btn:hover{background:#1b3355;border-color:#c8d8e8;transform:rotate(-12deg)}

/* soft aurora behind every inner page */
main{position:relative;isolation:isolate}
main::before{content:"";position:absolute;left:0;right:0;top:0;height:420px;z-index:-1;pointer-events:none;
  background:radial-gradient(640px 260px at 12% -40px,rgba(41,100,253,.10),transparent 70%),radial-gradient(520px 240px at 92% -30px,rgba(238,120,120,.10),transparent 70%),radial-gradient(400px 200px at 55% -60px,rgba(111,107,242,.08),transparent 70%)}
body.flush main::before{display:none}
.qc-dark main::before{opacity:.6}

/* page enter */
.pg-in{animation:pgIn .45s cubic-bezier(.2,.7,.2,1) both}
@keyframes pgIn{from{opacity:.001;transform:translateY(10px)}to{opacity:1;transform:none}}

/* headings on inner pages */
main h1{font-size:clamp(32px,4.2vw,48px);letter-spacing:-.025em;line-height:1.08}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font:600 12px var(--sans);letter-spacing:.14em;text-transform:uppercase;color:var(--accent);margin-bottom:10px}
.eyebrow::before{content:"";width:18px;height:2px;border-radius:2px;background-image:linear-gradient(90deg,#2964fd,#ee7878)}
.h2s{font-size:24px!important;letter-spacing:-.01em}

/* scroll reveal */
.js-rv .rvl{opacity:.001;transform:translateY(18px);transition:opacity .6s cubic-bezier(.2,.7,.2,1),transform .6s cubic-bezier(.2,.7,.2,1);transition-delay:var(--d,0ms)}
.js-rv .rvl.in{opacity:1;transform:none}

/* buttons: shine + arrow */
.btn.pri{position:relative;overflow:hidden;isolation:isolate}
.btn.pri::after{content:"";position:absolute;inset:0;z-index:-1;background:linear-gradient(105deg,transparent 35%,rgba(255,255,255,.35) 50%,transparent 65%);transform:translateX(-120%);transition:transform .7s ease}
.btn.pri:hover::after{transform:translateX(120%)}
.btn .arr{display:inline-block;transition:transform .2s ease}
.btn:hover .arr{transform:translateX(4px)}
.btn:focus-visible,.card:focus-visible,a:focus-visible,button:focus-visible{outline:2px solid var(--accent);outline-offset:3px}

/* cards: spotlight + gradient edge */
.card{position:relative;overflow:hidden;isolation:isolate;border-radius:16px}
.card::before{content:"";position:absolute;inset:0;z-index:-1;opacity:0;transition:opacity .3s;background:radial-gradient(360px circle at var(--mx,50%) var(--my,0%),rgba(41,100,253,.10),transparent 45%)}
.card:hover::before{opacity:1}
.card::after{content:"";position:absolute;inset:0;border-radius:inherit;padding:1px;background:linear-gradient(135deg,rgba(41,100,253,.55),rgba(238,120,120,.45));-webkit-mask:linear-gradient(#000 0 0) content-box,linear-gradient(#000 0 0);-webkit-mask-composite:xor;mask-composite:exclude;opacity:0;transition:opacity .3s;pointer-events:none}
.card:hover::after{opacity:1}
.card.navy::before{background:radial-gradient(360px circle at var(--mx,50%) var(--my,0%),rgba(127,166,255,.22),transparent 45%)}

/* section icons */
.sico{width:44px;height:44px;border-radius:12px;display:inline-flex;align-items:center;justify-content:center;background:var(--accent-soft);color:var(--accent);flex:none;transition:transform .3s cubic-bezier(.2,1.4,.4,1)}
.card:hover .sico{transform:rotate(-6deg) scale(1.06)}
.sico.live{background-image:linear-gradient(135deg,#2964fd,#6f6bf2 60%,#ee7878);color:#fff;box-shadow:0 10px 22px -12px rgba(41,100,253,.8)}
.sico svg{width:22px;height:22px}
.card.muted{background:color-mix(in srgb,var(--panel) 70%,var(--bg))}
.card.muted h3{color:var(--ink2)}
.card .meta2{display:flex;gap:14px;font:500 12.5px var(--mono);color:var(--ink3);margin-top:auto;padding-top:6px}
.card .meta2 b{color:var(--ink);font-weight:600}

/* progress bars animate in */
.bar i,.track i{transition:width 1.1s cubic-bezier(.2,.7,.2,1)}
.bar-pending .bar i,.bar-pending .track i{width:0!important}

/* hero: grid, glyphs, glow */
.hero2{position:relative;overflow:hidden;isolation:isolate}
.hero2::before{content:"";position:absolute;inset:0;z-index:-2;background-image:linear-gradient(rgba(200,216,232,.06) 1px,transparent 1px),linear-gradient(90deg,rgba(200,216,232,.06) 1px,transparent 1px);background-size:44px 44px;-webkit-mask-image:radial-gradient(ellipse at 30% 40%,#000 20%,transparent 75%);mask-image:radial-gradient(ellipse at 30% 40%,#000 20%,transparent 75%)}
.hero2::after{content:"";position:absolute;width:680px;height:680px;right:-140px;top:-220px;z-index:-2;background:radial-gradient(circle,rgba(111,107,242,.35),rgba(238,120,120,.12) 45%,transparent 70%);filter:blur(10px);animation:glow 9s ease-in-out infinite alternate}
@keyframes glow{to{transform:translate(-60px,50px) scale(1.08)}}
.glyphs{position:absolute;inset:0;z-index:-1;pointer-events:none;overflow:hidden}
.glyphs span{position:absolute;font:500 22px var(--mono);color:rgba(200,216,232,.13);animation:drift 16s ease-in-out infinite alternate}
@keyframes drift{from{transform:translateY(0) rotate(0)}to{transform:translateY(-28px) rotate(6deg)}}
.qcard{position:relative;animation:float 7s ease-in-out infinite}
@keyframes float{50%{transform:translateY(-6px)}}
.qcard{box-shadow:0 30px 60px -30px rgba(0,0,0,.6),0 0 0 1px rgba(255,255,255,.06),0 0 80px -20px rgba(111,107,242,.55)}
.live-dot{display:inline-flex;align-items:center;gap:6px;font:600 12px var(--sans);color:var(--easy)}
.live-dot::before{content:"";width:7px;height:7px;border-radius:99px;background:currentColor;box-shadow:0 0 0 0 currentColor;animation:ping 1.8s infinite}
@keyframes ping{0%{box-shadow:0 0 0 0 rgba(21,128,61,.5)}70%{box-shadow:0 0 0 8px rgba(21,128,61,0)}100%{box-shadow:0 0 0 0 rgba(21,128,61,0)}}

/* steps flow line */
.steps3{position:relative}
.steps3 div{position:relative;transition:transform .25s,box-shadow .25s}
.steps3 div:hover{transform:translateY(-4px);box-shadow:0 18px 36px -20px rgba(20,40,67,.35)}
.steps3 .n{display:inline-flex;align-items:center;gap:10px}
.steps3 .n i{width:30px;height:30px;border-radius:99px;display:inline-flex;align-items:center;justify-content:center;font-style:normal;color:#fff;background-image:var(--grad);font:600 13px var(--mono)}
@media (min-width:761px){.steps3 div:not(:last-child)::after{content:"";position:absolute;top:43px;right:-21px;width:22px;height:2px;background-image:linear-gradient(90deg,#2964fd,#ee7878);z-index:2}}

/* numbers band */
.nband{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0;border:1px solid var(--line);border-radius:20px;background:var(--panel);margin-top:56px;overflow:hidden}
.nband div{padding:28px 26px;display:flex;flex-direction:column;gap:4px;border-right:1px solid var(--line)}
.nband div:last-child{border-right:0}
.nband b{font:700 clamp(30px,3.4vw,44px)/1 var(--serif);letter-spacing:-.02em;background-image:linear-gradient(90deg,#142843,#2964fd);-webkit-background-clip:text;background-clip:text;color:transparent}
.qc-dark .nband b{background-image:linear-gradient(90deg,#e6eef7,#7fa6ff)}
.nband span{font-size:14px;color:var(--ink2)}
@media (max-width:760px){.nband{grid-template-columns:repeat(2,minmax(0,1fr))}.nband div:nth-child(2){border-right:0}.nband div:nth-child(-n+2){border-bottom:1px solid var(--line)}}

/* hub header with ring */
.hubhead{display:flex;gap:28px;align-items:center;justify-content:space-between;flex-wrap:wrap;padding:28px;border-radius:22px;background:var(--panel);border:1px solid var(--line);margin:8px 0 26px;box-shadow:0 20px 40px -32px rgba(20,40,67,.45)}
.hubhead .l{display:flex;gap:18px;align-items:flex-start;flex:1;min-width:260px}
.hubhead .sico{width:56px;height:56px;border-radius:16px}.hubhead .sico svg{width:28px;height:28px}
.hubhead h1{margin:0 0 6px}
.hubhead p{margin:0;color:var(--ink2);max-width:62ch}
.ring{position:relative;width:112px;height:112px;flex:none}
.ring svg{transform:rotate(-90deg)}
.ring .rt{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;font:600 22px var(--mono)}
.ring .rt small{font:500 11px var(--sans);color:var(--ink3);letter-spacing:.06em;text-transform:uppercase}
.ring circle.fg{transition:stroke-dashoffset 1.3s cubic-bezier(.2,.7,.2,1)}

/* lesson list + hub columns */
.lesson-list a{transition:transform .2s,border-color .2s,box-shadow .2s}
.lesson-list a:hover{transform:translateX(4px);box-shadow:0 12px 26px -20px rgba(20,40,67,.5)}
.lesson-list .ln{width:36px;height:36px;border-radius:10px;display:inline-flex;align-items:center;justify-content:center;background:var(--accent-soft);color:var(--accent)!important}

/* practice table */
.qt tbody tr{transition:background .15s}
.qt tbody tr td:first-child{border-left:3px solid transparent;transition:border-color .15s}
.qt tbody tr:hover td:first-child{border-left-color:var(--accent)}
.chip{transition:transform .15s,background .15s,border-color .15s}
.chip:hover{transform:translateY(-1px)}

/* KPI cards */
.kpi,.kpi3 div{position:relative;overflow:hidden;transition:transform .25s,box-shadow .25s}
.kpi:hover,.kpi3 div:hover{transform:translateY(-3px);box-shadow:0 16px 32px -22px rgba(20,40,67,.5)}
.kpi::after,.kpi3 div::after{content:"";position:absolute;left:0;right:0;top:0;height:3px;background-image:linear-gradient(90deg,#2964fd,#6f6bf2,#ee7878)}

/* heatmap fix */
.heat{grid-auto-columns:12px;justify-content:start}
.heat i{transition:transform .15s}.heat i:hover{transform:scale(1.4)}

/* celebration */
.burst{position:fixed;pointer-events:none;z-index:90;width:8px;height:8px;border-radius:2px;will-change:transform,opacity}
.plus-pts{position:fixed;z-index:91;pointer-events:none;font:700 22px var(--serif);background-image:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;animation:plus 1.1s cubic-bezier(.2,.7,.2,1) forwards}
@keyframes plus{from{opacity:0;transform:translate(-50%,0) scale(.8)}20%{opacity:1}to{opacity:0;transform:translate(-50%,-60px) scale(1.1)}}

/* sidebar polish */
.side{scrollbar-width:thin}
.nav-sec{transition:background .15s,color .15s,transform .15s}
.nav-sec:hover{transform:translateX(2px)}

@media (prefers-reduced-motion:reduce){
  .js-rv .rvl{opacity:1;transform:none;transition:none}
  .pg-in,.qcard,.hero2::after,.glyphs span,.live-dot::before,.plus-pts{animation:none}
  .bar i,.track i,.ring circle.fg{transition:none}
}

.qcard:hover,.qcard:focus-within{animation-play-state:paused}
.card .meta2 span{display:inline-flex;gap:5px;align-items:baseline;white-space:nowrap}.card .meta2 b{display:inline}.ring .rt small{font-size:10px;letter-spacing:.04em}
.hero2,.ticker2{margin-left:calc(50% - 50vw);margin-right:calc(50% - 50vw);padding-left:max(var(--gut),calc(50vw - 640px));padding-right:max(var(--gut),calc(50vw - 640px))}.ticker2{padding-left:0;padding-right:0}html,body{overflow-x:clip}
.ticker2{-webkit-mask-image:none;mask-image:none;position:relative}.ticker2::before,.ticker2::after{content:"";position:absolute;top:0;bottom:0;width:140px;z-index:1;pointer-events:none}.ticker2::before{left:0;background:linear-gradient(90deg,#0e1e36,transparent)}.ticker2::after{right:0;background:linear-gradient(-90deg,#0e1e36,transparent)}.ticker2 .ticker-in span{transition:color .2s}.ticker2 .ticker-in span:hover{color:#c8d8e8}