/* ------------------------------------------------------------------
   NUS Stack prototype – design system
   Warm paper base, NUS blue for structure, NUS orange for one accent.
------------------------------------------------------------------ */
:root{
  --paper:#FAF7F1; --paper-2:#F3EEE4; --surface:#FFFFFF;
  --ink:#1B1A17; --ink-2:#4A463F; --muted:#7A7468; --line:#E6DFD3; --line-2:#D8CFBF;
  --blue:#003D7C; --blue-2:#0A4F97; --blue-soft:#E6EEF7; --blue-tint:#F2F6FB;
  --orange:#EF7C00; --orange-soft:#FDEBD9;
  --green:#2E7D4F; --green-soft:#E3F1E8; --red:#B23A2E; --red-soft:#F8E4E1;
  --serif:'Fraunces', Georgia, 'Times New Roman', serif;
  --sans:'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --r:14px; --r-sm:9px; --r-lg:22px;
  --shadow:0 1px 2px rgba(27,26,23,.04), 0 8px 24px -12px rgba(27,26,23,.14);
  --shadow-lg:0 2px 4px rgba(27,26,23,.04), 0 24px 48px -20px rgba(0,61,124,.22);
  --max:1180px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased;
  background-image:radial-gradient(1200px 500px at 80% -10%, rgba(0,61,124,.05), transparent 60%);}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%}
h1,h2,h3,h4{font-family:var(--serif);font-weight:500;letter-spacing:-.01em;line-height:1.12;margin:0 0 .5em;color:var(--ink);font-variation-settings:"opsz" 96}
h1{font-size:clamp(2.1rem,4.4vw,3.6rem)} h2{font-size:clamp(1.6rem,2.8vw,2.3rem)} h3{font-size:1.3rem;font-variation-settings:"opsz" 36} h4{font-size:1.05rem;font-family:var(--sans);font-weight:600}
p{margin:0 0 1em} .lead{font-size:1.15rem;color:var(--ink-2);max-width:62ch}
.muted{color:var(--muted)} .small{font-size:.86rem} .tiny{font-size:.76rem;letter-spacing:.04em;text-transform:uppercase;color:var(--muted);font-weight:600}
.display{font-variation-settings:"opsz" 144,"SOFT" 30}
.em{font-style:italic;font-variation-settings:"opsz" 144,"SOFT" 50;color:var(--blue)}
main{min-height:60vh}
main > section, main > .wrap{max-width:var(--max);margin:0 auto;padding:48px 24px}
main.wide > section{max-width:1320px}
.narrow{max-width:760px !important}
.center{text-align:center}
.grid{display:grid;gap:20px}
.g2{grid-template-columns:repeat(2,1fr)} .g3{grid-template-columns:repeat(3,1fr)} .g4{grid-template-columns:repeat(4,1fr)}
.g-aside{grid-template-columns:1fr 360px;align-items:start}
.g-lesson{grid-template-columns:minmax(0,1fr) 440px;align-items:start}
@media(max-width:1000px){.g3,.g4{grid-template-columns:repeat(2,1fr)} .g-aside,.g-lesson{grid-template-columns:1fr}}
@media(max-width:640px){.g2,.g3,.g4{grid-template-columns:1fr} main > section{padding:32px 16px}}

/* header */
.top{position:sticky;top:0;z-index:50;background:rgba(250,247,241,.86);backdrop-filter:saturate(1.4) blur(12px);border-bottom:1px solid var(--line)}
.top-inner{max-width:var(--max);margin:0 auto;padding:12px 24px;display:flex;align-items:center;justify-content:space-between;gap:16px}
.brand{display:flex;align-items:center;gap:12px;color:var(--ink)}
.brand:hover{text-decoration:none}
.nus-logo{height:52px;width:auto;display:block}
@media(max-width:600px){.nus-logo{height:40px}}
.nus-text{display:flex;align-items:center;gap:8px}
.nus-text-big{font-family:var(--serif);font-weight:600;font-size:1.5rem;color:var(--blue);letter-spacing:.02em}
.nus-text-small{font-size:.62rem;line-height:1.15;text-transform:uppercase;letter-spacing:.06em;color:var(--ink-2);font-weight:600}
.brand-sep{width:1px;height:30px;background:var(--line-2)}
.wordmark{font-family:var(--serif);font-weight:500;font-size:1.45rem;letter-spacing:-.01em;font-variation-settings:"opsz" 48}
.nav{display:flex;align-items:center;gap:22px;font-size:.92rem;font-weight:500}
.nav a{color:var(--ink-2)} .nav a:hover{color:var(--blue);text-decoration:none}
.nav a.btn-primary,.nav a.btn-primary:hover{color:#fff}
.nav .nav-muted{color:var(--muted)} .nav-user{color:var(--muted);font-weight:500;padding-left:6px;border-left:1px solid var(--line-2)}
.nav-toggle{display:none;background:none;border:0;width:40px;height:40px;cursor:pointer;flex-direction:column;gap:6px;align-items:center;justify-content:center}
.nav-toggle span{display:block;width:22px;height:2px;background:var(--ink)}
@media(max-width:900px){
  .nav{display:none;position:absolute;left:0;right:0;top:100%;background:var(--paper);border-bottom:1px solid var(--line);padding:16px 24px;flex-direction:column;align-items:flex-start;gap:14px}
  body.nav-open .nav{display:flex} .nav-toggle{display:flex} .nav-user{border:0;padding:0}
}
.flash{max-width:var(--max);margin:16px auto 0;padding:12px 18px;background:var(--green-soft);color:var(--green);border-radius:var(--r-sm);font-weight:500}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 20px;border-radius:999px;font-weight:600;font-size:.95rem;border:1px solid transparent;cursor:pointer;font-family:var(--sans);transition:transform .15s ease, box-shadow .15s ease, background .15s ease;line-height:1.1}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:var(--blue);color:#fff;box-shadow:0 6px 16px -8px rgba(0,61,124,.6)} .btn-primary:hover{background:var(--blue-2)}
.btn-accent{background:var(--orange);color:#fff;box-shadow:0 6px 16px -8px rgba(239,124,0,.6)} .btn-accent:hover{background:#d96f00}
.btn-ghost{background:transparent;color:var(--ink);border-color:var(--line-2)} .btn-ghost:hover{background:var(--surface)}
.btn-soft{background:var(--blue-soft);color:var(--blue)} .btn-soft:hover{background:#d9e6f4}
.btn-sm{padding:8px 14px;font-size:.86rem} .btn-lg{padding:15px 28px;font-size:1.05rem}
.btn[disabled]{opacity:.45;pointer-events:none}
.btn-block{width:100%;justify-content:center}

/* cards & surfaces */
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:24px;box-shadow:var(--shadow)}
.card-tint{background:var(--blue-tint);border-color:#D5E1EF}
.card-paper{background:var(--paper-2);border-color:var(--line-2);box-shadow:none}
.card h3{margin-top:0}
.pill{display:inline-flex;align-items:center;gap:6px;padding:4px 11px;border-radius:999px;font-size:.76rem;font-weight:600;letter-spacing:.02em;background:var(--paper-2);color:var(--ink-2);border:1px solid var(--line)}
.pill-blue{background:var(--blue-soft);color:var(--blue);border-color:transparent}
.pill-orange{background:var(--orange-soft);color:#9a4d00;border-color:transparent}
.pill-green{background:var(--green-soft);color:var(--green);border-color:transparent}
.pill-red{background:var(--red-soft);color:var(--red);border-color:transparent}
.eyebrow{font-size:.78rem;font-weight:600;letter-spacing:.1em;text-transform:uppercase;color:var(--orange);margin-bottom:12px;display:block}
.rule{height:1px;background:var(--line);margin:28px 0}
.stack{display:flex;flex-direction:column;gap:12px}
.row{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.between{justify-content:space-between}
.mt{margin-top:24px} .mt-lg{margin-top:48px} .mb{margin-bottom:24px}

/* hero */
.hero{padding-top:72px !important;padding-bottom:40px !important}
.hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center}
@media(max-width:900px){.hero-grid{grid-template-columns:1fr}}
.hero h1{margin-bottom:20px}
.hero-card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);padding:28px;box-shadow:var(--shadow-lg);position:relative}
.hero-card::before{content:"";position:absolute;inset:-1px;border-radius:inherit;background:linear-gradient(135deg,rgba(239,124,0,.25),rgba(0,61,124,.1) 50%,transparent);z-index:-1;filter:blur(18px);opacity:.7}
.price-big{font-family:var(--serif);font-size:3rem;font-weight:500;color:var(--blue);line-height:1;font-variation-settings:"opsz" 144}
.price-big small{font-size:1rem;color:var(--muted);font-family:var(--sans);font-weight:500;margin-left:6px}
.stat{display:flex;flex-direction:column;gap:2px}
.stat b{font-family:var(--serif);font-size:1.7rem;font-weight:500;color:var(--ink);line-height:1.1}
.stat span{font-size:.82rem;color:var(--muted)}

/* journey steps */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;counter-reset:s}
@media(max-width:900px){.steps{grid-template-columns:repeat(2,1fr)}} @media(max-width:560px){.steps{grid-template-columns:1fr}}
.step{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:22px;position:relative;counter-increment:s}
.step::before{content:counter(s,decimal-leading-zero);font-family:var(--serif);font-size:2.2rem;color:var(--line-2);position:absolute;top:14px;right:18px;font-variation-settings:"opsz" 144;line-height:1}
.step.active{border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-soft)}
.step .price{font-family:var(--serif);font-size:1.35rem;color:var(--blue);margin-top:12px}
.step ul{padding-left:18px;margin:10px 0 0;color:var(--ink-2);font-size:.92rem} .step li{margin-bottom:4px}

/* compare table */
.compare{width:100%;border-collapse:separate;border-spacing:0;background:var(--surface);border:1px solid var(--line);border-radius:var(--r);overflow:hidden;font-size:.95rem}
.compare th,.compare td{padding:14px 18px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
.compare tr:last-child td{border-bottom:0}
.compare th{background:var(--paper-2);font-weight:600;font-size:.84rem;letter-spacing:.03em;text-transform:uppercase;color:var(--ink-2)}
.compare .hl{background:var(--blue-tint)}
.compare .total td{font-weight:600;font-size:1.05rem;background:var(--paper-2)}
.compare .delta{color:var(--green);font-weight:600}

/* side-by-side application comparison */
.sbs{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:start}
@media(max-width:900px){.sbs{grid-template-columns:1fr}}
.sbs .old{opacity:.82}
.checklist{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:10px}
.checklist li{display:flex;gap:10px;align-items:flex-start;font-size:.95rem;color:var(--ink-2)}
.checklist .ok::before{content:"✓";color:var(--green);font-weight:700;flex:0 0 18px}
.checklist .no::before{content:"×";color:var(--red);font-weight:700;flex:0 0 18px}
.checklist .x::before{content:"–";color:var(--muted);flex:0 0 18px}

/* forms */
label{display:block;font-size:.86rem;font-weight:600;color:var(--ink-2);margin-bottom:6px}
input[type=text],input[type=email],input[type=password],select,textarea{width:100%;padding:12px 14px;border:1px solid var(--line-2);border-radius:var(--r-sm);font:inherit;font-size:.95rem;background:var(--surface);color:var(--ink);transition:border .15s, box-shadow .15s}
input:focus,select:focus,textarea:focus{outline:0;border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-soft)}
textarea{min-height:120px;resize:vertical}
.field{margin-bottom:18px}
.radio-cards{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.radio-cards label{position:relative;display:block;padding:14px;border:1px solid var(--line-2);border-radius:var(--r-sm);cursor:pointer;background:var(--surface);font-weight:500;margin:0}
.radio-cards input{position:absolute;opacity:0}
.radio-cards input:checked + span{color:var(--blue)}
.radio-cards label:has(input:checked){border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-soft)}
.radio-cards small{display:block;color:var(--muted);font-weight:400;margin-top:3px}
.error{background:var(--red-soft);color:var(--red);padding:10px 14px;border-radius:var(--r-sm);font-size:.9rem;margin-bottom:16px}

/* progress */
.bar{height:8px;background:var(--paper-2);border-radius:999px;overflow:hidden;border:1px solid var(--line)}
.bar > i{display:block;height:100%;background:linear-gradient(90deg,var(--blue),var(--blue-2));border-radius:999px;transition:width .5s ease}
.bar.orange > i{background:var(--orange)}
.lesson-list{list-style:none;margin:0;padding:0}
.lesson-list li{display:flex;align-items:center;gap:14px;padding:14px 0;border-bottom:1px solid var(--line)}
.lesson-list li:last-child{border-bottom:0}
.lesson-list .n{width:34px;height:34px;border-radius:50%;display:grid;place-items:center;font-size:.8rem;font-weight:700;background:var(--paper-2);color:var(--muted);flex:0 0 34px;border:1px solid var(--line)}
.lesson-list .done .n{background:var(--green);color:#fff;border-color:var(--green)}
.lesson-list .now .n{background:var(--blue);color:#fff;border-color:var(--blue)}
.lesson-list .t{flex:1} .lesson-list .t b{display:block;font-weight:600} .lesson-list .t span{font-size:.85rem;color:var(--muted)}

/* tabs */
.tabs{display:flex;gap:4px;border-bottom:1px solid var(--line);margin-bottom:22px}
.tabs button{background:none;border:0;padding:10px 14px;font:inherit;font-weight:600;color:var(--muted);cursor:pointer;border-bottom:2px solid transparent;margin-bottom:-1px}
.tabs button.on{color:var(--blue);border-color:var(--blue)}
.tab-pane{display:none} .tab-pane.on{display:block}

/* lesson + coach */
.notes h2{margin-top:36px}
.notes p{color:var(--ink-2);font-size:1.02rem;line-height:1.7;max-width:66ch}
.notes .reading{border-left:3px solid var(--orange);padding:8px 16px;background:var(--surface);border-radius:0 var(--r-sm) var(--r-sm) 0;font-size:.95rem}
.coach{position:sticky;top:84px;background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);box-shadow:var(--shadow-lg);display:flex;flex-direction:column;height:min(78vh,760px);overflow:hidden}
.coach-head{padding:16px 20px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:10px;background:linear-gradient(180deg,var(--blue-tint),var(--surface))}
.coach-head b{display:flex;align-items:center;gap:8px}
.coach-dot{width:9px;height:9px;border-radius:50%;background:var(--green);box-shadow:0 0 0 3px var(--green-soft)}
.coach-body{flex:1;overflow:auto;padding:20px;display:flex;flex-direction:column;gap:14px;scroll-behavior:smooth}
.msg{max-width:88%;padding:12px 16px;border-radius:18px;font-size:.95rem;line-height:1.5;animation:pop .25s ease}
.msg.c{background:var(--paper-2);border-bottom-left-radius:6px;align-self:flex-start}
.msg.l{background:var(--blue);color:#fff;border-bottom-right-radius:6px;align-self:flex-end}
.msg.sys{align-self:center;background:transparent;color:var(--muted);font-size:.8rem;text-align:center;max-width:100%}
@keyframes pop{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.typing{display:inline-flex;gap:4px;padding:8px 2px} .typing i{width:6px;height:6px;border-radius:50%;background:var(--muted);animation:blink 1s infinite} .typing i:nth-child(2){animation-delay:.2s} .typing i:nth-child(3){animation-delay:.4s}
@keyframes blink{0%,80%,100%{opacity:.25}40%{opacity:1}}
.coach-foot{border-top:1px solid var(--line);padding:12px 14px;background:var(--surface)}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:10px}
.chip{background:var(--surface);border:1px solid var(--blue);color:var(--blue);padding:7px 12px;border-radius:999px;font-size:.84rem;font-weight:500;cursor:pointer;font-family:var(--sans)}
.chip:hover{background:var(--blue-soft)}
.coach-input{display:flex;gap:8px}
.coach-input input{flex:1}
.rubric{display:flex;gap:4px} .rubric i{flex:1;height:6px;border-radius:3px;background:var(--line)} .rubric i.on{background:var(--orange)}
.mode{display:inline-flex;background:var(--paper-2);border:1px solid var(--line);border-radius:999px;padding:3px}
.mode button{border:0;background:none;padding:7px 14px;border-radius:999px;font:inherit;font-size:.86rem;font-weight:600;color:var(--muted);cursor:pointer}
.mode button.on{background:var(--surface);color:var(--blue);box-shadow:var(--shadow)}
body.notes-only .coach,body.notes-only .coach-col{display:none}
body.notes-only .g-lesson{grid-template-columns:minmax(0,760px)}
.notes-only-note{display:none;background:var(--orange-soft);border-radius:var(--r-sm);padding:12px 16px;font-size:.92rem;color:#7a3e00;margin-bottom:20px}
body.notes-only .notes-only-note{display:block}

/* exam */
.exam-top{position:sticky;top:64px;z-index:5;background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:12px 18px;display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:20px;box-shadow:var(--shadow)}
.timer{font-family:var(--serif);font-size:1.5rem;font-variation-settings:"opsz" 96;color:var(--blue);font-variant-numeric:tabular-nums}
.timer.low{color:var(--red)}
.q{margin-bottom:22px}
.q .qt{font-weight:600;margin-bottom:10px}
.opts{display:grid;gap:8px}
.opts label{display:flex;gap:12px;align-items:flex-start;padding:12px 14px;border:1px solid var(--line-2);border-radius:var(--r-sm);background:var(--surface);cursor:pointer;font-weight:400;margin:0}
.opts label:has(input:checked){border-color:var(--blue);background:var(--blue-tint)}
.opts input{margin-top:3px}
.precheck{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
@media(max-width:700px){.precheck{grid-template-columns:1fr}}
.precheck .card{text-align:center}
.cam{width:100%;aspect-ratio:4/3;background:#111;border-radius:var(--r-sm);object-fit:cover;display:block}
.status-ok{color:var(--green);font-weight:600} .status-wait{color:var(--muted)}

/* oral */
.oral-q{font-family:var(--serif);font-size:1.5rem;line-height:1.3;font-variation-settings:"opsz" 96;margin-bottom:16px}
.mic{width:72px;height:72px;border-radius:50%;border:0;background:var(--blue);color:#fff;display:grid;place-items:center;cursor:pointer;box-shadow:0 8px 20px -8px rgba(0,61,124,.6)}
.mic.on{background:var(--red);animation:pulse 1.2s infinite}
@keyframes pulse{0%{box-shadow:0 0 0 0 rgba(178,58,46,.4)}100%{box-shadow:0 0 0 18px rgba(178,58,46,0)}}

/* results */
.offer{background:var(--surface);border:1px solid var(--line);border-radius:var(--r-lg);padding:48px;box-shadow:var(--shadow-lg);position:relative;overflow:hidden}
.offer::after{content:"";position:absolute;top:0;left:0;right:0;height:6px;background:linear-gradient(90deg,var(--blue),var(--orange))}
.offer .checklist{margin-bottom:20px}
.offer .sig{font-family:var(--serif);font-style:italic;color:var(--blue);font-size:1.4rem}
.cert{border:2px solid var(--blue);padding:40px;text-align:center;border-radius:var(--r);background:var(--surface)}
.grade-tile{display:flex;align-items:center;justify-content:space-between;padding:14px 18px;border:1px solid var(--line);border-radius:var(--r-sm);background:var(--surface)}
.grade-tile b.g{font-family:var(--serif);font-size:1.3rem;color:var(--blue)}

/* timetable */
.tt{width:100%;border-collapse:collapse;font-size:.92rem}
.tt td{padding:12px 10px;border-bottom:1px solid var(--line);vertical-align:top}
.tt td:first-child{font-weight:600;width:84px} .tt td:last-child{text-align:right;white-space:nowrap;color:var(--muted)}

/* kpis */
.kpi{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:18px 20px}
.kpi .v{font-family:var(--serif);font-size:2rem;color:var(--blue);line-height:1;font-variation-settings:"opsz" 144;margin:6px 0}
.kpi .t{font-size:.78rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted);font-weight:600}
.kpi .s{font-size:.84rem;color:var(--ink-2)}
.gate-row{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
@media(max-width:800px){.gate-row{grid-template-columns:1fr}}

/* persona cards */
.persona{display:flex;gap:14px;align-items:flex-start;text-align:left;padding:18px;border:1px solid var(--line-2);border-radius:var(--r);background:var(--surface);cursor:pointer;width:100%;font:inherit;transition:border .15s, box-shadow .15s}
.persona:hover{border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-soft)}
.avatar{width:44px;height:44px;border-radius:50%;display:grid;place-items:center;font-family:var(--serif);font-weight:600;color:#fff;background:var(--blue);flex:0 0 44px}
.avatar.o{background:var(--orange)} .avatar.g{background:var(--green)}

/* footer */
.foot{border-top:1px solid var(--line);margin-top:64px;background:var(--paper-2)}
.foot-inner{max-width:var(--max);margin:0 auto;padding:28px 24px;display:flex;justify-content:space-between;gap:24px;align-items:center;flex-wrap:wrap}
.foot .mark{vertical-align:-4px}

/* gate */
.gate-wrap{min-height:70vh;display:grid;place-items:center}
.gate-card{max-width:420px;width:100%}

/* file list */
.files{list-style:none;padding:0;margin:0;display:grid;gap:8px}
.files li{display:flex;align-items:center;gap:12px;padding:12px 14px;border:1px solid var(--line);border-radius:var(--r-sm);background:var(--surface);font-size:.92rem}
.files .ext{font-size:.68rem;font-weight:700;letter-spacing:.06em;padding:4px 7px;border-radius:5px;background:var(--blue-soft);color:var(--blue);text-transform:uppercase}
.files .ext.pptx{background:var(--orange-soft);color:#9a4d00}
.empty{border:1px dashed var(--line-2);border-radius:var(--r);padding:28px;text-align:center;color:var(--muted);background:transparent}
.viewer{width:100%;height:72vh;border:1px solid var(--line);border-radius:var(--r);background:#fff}