/* ============================================================
   Desvantage — light premium theme (SAT/ACT Desmos training)
   Navy #0b1f3a text on white/#f6fafb, teal #12b3a6 accent.
   ============================================================ */
:root{
  --teal:#12b3a6; --teal-d:#0e9e93; --teal-tint:#e6f7f5; --teal-tint2:#f1fbfa;
  --navy:#0b1f3a; --navy-2:#0d2748; --ink:#1c2b45; --ink-soft:#475569;
  --muted:#8a97a8; --line:#e7edf3; --line-soft:#eef3f8; --bg:#f6fafb; --gold:#f5b301;
  --shadow:0 10px 30px rgba(11,31,58,.07); --shadow-lg:0 30px 70px rgba(11,31,58,.16);
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font:400 1.02rem/1.7 Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:#fff}
h1,h2,h3{font-family:Poppins,Inter,sans-serif;line-height:1.18;color:var(--navy)}
img,svg,video{max-width:100%;display:block}
a{color:var(--teal-d);text-decoration:none}
.wrap{max-width:1140px;margin:0 auto;padding:0 24px}

.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;cursor:pointer;text-decoration:none;text-align:center;font:700 1rem Poppins,sans-serif;border-radius:12px;padding:14px 26px;transition:transform .15s,box-shadow .15s,background .15s}
.btn:hover{transform:translateY(-1px)}
.btn-teal{background:var(--teal);color:#fff;box-shadow:0 8px 20px rgba(18,179,166,.28)}
.btn-teal:hover{background:var(--teal-d)}
.btn-outline{background:#fff;color:var(--navy);border:1.6px solid var(--line)}
.btn-outline:hover{border-color:var(--teal);color:var(--teal-d)}
.btn-lg{font-size:1.06rem;padding:16px 32px}
.btn-block{width:100%}
.btn-sm{font-size:.86rem;padding:9px 16px;border-radius:10px}
.linklike{background:none;border:0;color:var(--teal-d);font:inherit;cursor:pointer;text-decoration:underline;padding:0}

/* ---- header ---- */
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);backdrop-filter:blur(10px);border-bottom:1px solid var(--line-soft)}
.header-inner{max-width:1140px;margin:0 auto;padding:14px 24px;display:flex;align-items:center;justify-content:space-between;gap:20px}
.brand-logo{height:44px}
.site-nav{display:flex;align-items:center;gap:30px}
.site-nav a{color:var(--ink-soft);font-weight:600;font-size:.95rem}
.site-nav a:hover{color:var(--teal-d)}
@media(max-width:820px){.site-nav a:not(.nav-cta){display:none}}

/* ---- hero ---- */
.hero{position:relative;overflow:hidden;padding:70px 0 80px}
.hero-grid{display:grid;grid-template-columns:1.05fr 1.15fr;gap:48px;align-items:center;position:relative;z-index:2}
.hero h1{font-size:clamp(2.3rem,4.6vw,3.5rem);font-weight:800;letter-spacing:-1px;line-height:1.1;margin-bottom:20px;text-wrap:balance;max-width:15ch}
.hero h1 .hl{color:var(--teal);display:block}
.hero .sub{font-size:1.16rem;color:var(--ink-soft);max-width:30em;line-height:1.7;margin-bottom:30px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap;margin-bottom:22px}
.price-badge{display:inline-flex;align-items:center;gap:0;background:var(--teal);color:#fff;border-radius:10px;overflow:hidden;font:800 1.1rem Poppins,sans-serif}
.price-badge b{padding:9px 16px}
.price-badge span{padding:9px 16px;background:rgba(255,255,255,.15);font-size:.82rem;font-weight:700;letter-spacing:.08em}
.hero-blob{position:absolute;right:-6%;top:6%;width:640px;height:520px;background:radial-gradient(circle at 60% 40%,var(--teal-tint),transparent 62%);z-index:1}
.dots{position:absolute;left:44%;top:12%;width:120px;height:110px;background-image:radial-gradient(var(--line) 1.6px,transparent 1.6px);background-size:15px 15px;opacity:.8;z-index:1}

/* laptop mockup */
.laptop{position:relative;z-index:2}
.laptop-screen{background:#0e1c33;border:10px solid #0e1c33;border-radius:16px 16px 0 0;box-shadow:var(--shadow-lg);overflow:hidden}
.laptop-base{height:14px;background:linear-gradient(#c8d2dd,#aeb9c6);border-radius:0 0 14px 14px;margin:0 -18px;position:relative}
.laptop-base::after{content:"";position:absolute;top:0;left:50%;transform:translateX(-50%);width:80px;height:5px;background:#8b97a6;border-radius:0 0 6px 6px}
.laptop-video{display:block;width:100%;height:auto;background:#0e1c33;aspect-ratio:16/10;object-fit:cover}
.app-ui{background:#fff;font-size:11px;color:var(--ink)}
.aui-top{display:flex;align-items:center;justify-content:space-between;padding:9px 12px;border-bottom:1px solid var(--line-soft)}
.aui-top .lg{height:16px}
.aui-a{width:20px;height:20px;border-radius:50%;background:var(--teal-tint);color:var(--teal-d);display:grid;place-items:center;font-weight:800;font-size:10px}
.aui-body{display:grid;grid-template-columns:118px 1fr 92px;min-height:210px}
.aui-side{background:#f7fafc;border-right:1px solid var(--line-soft);padding:12px 10px;display:flex;flex-direction:column;gap:9px}
.aui-step{display:flex;align-items:center;gap:8px;color:var(--muted);font-weight:600}
.aui-step .n{width:16px;height:16px;border-radius:50%;background:#e7edf3;color:var(--muted);display:grid;place-items:center;font-size:9px;font-weight:800;flex:0 0 auto}
.aui-step.done{color:var(--ink-soft)} .aui-step.done .n{background:var(--teal-tint);color:var(--teal-d)}
.aui-step.on{color:var(--navy);font-weight:800} .aui-step.on .n{background:var(--teal);color:#fff}
.aui-step .ck{margin-left:auto;color:var(--teal)}
.aui-main{padding:12px 14px}
.aui-main h4{font-size:13px;margin-bottom:2px}
.aui-main .mut{color:var(--muted);margin-bottom:8px}
.aui-eq{color:var(--teal-d);font-family:ui-monospace,monospace;font-size:11px;line-height:1.7}
.aui-graph{margin-top:8px;border:1px solid var(--line-soft);border-radius:8px}
.aui-r{padding:12px 10px;border-left:1px solid var(--line-soft);display:flex;flex-direction:column;gap:12px}
.aui-r .lab{color:var(--muted);font-size:9px;text-transform:uppercase;letter-spacing:.04em}
.aui-r .val{font-weight:800;color:var(--navy);font-size:13px}
.ring{width:60px;height:60px;margin:2px auto 0;border-radius:50%;background:conic-gradient(var(--teal) 85%,#e7edf3 0);display:grid;place-items:center}
.ring::after{content:"85%";width:44px;height:44px;background:#fff;border-radius:50%;display:grid;place-items:center;font-weight:800;font-size:12px;color:var(--navy)}
.aui-next{display:flex;align-items:center;justify-content:space-between;border-top:1px solid var(--line-soft);padding-top:8px;margin-top:auto}
.aui-next .arw{width:18px;height:18px;border-radius:50%;background:var(--teal);color:#fff;display:grid;place-items:center;font-size:10px}

/* ---- section heading ---- */
section{padding:66px 0}
.sec-head{text-align:center;margin-bottom:38px}
.sec-head h2{font-size:clamp(1.7rem,3.4vw,2.2rem);font-weight:800}
.sec-head .rule{width:64px;height:4px;background:var(--teal);border-radius:2px;margin:14px auto 0}
.sec-head p{color:var(--ink-soft);margin-top:12px;max-width:36em;margin-left:auto;margin-right:auto}
.sec-alt{background:var(--bg)}

/* ---- feature cards ---- */
.cards-3{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.cards-4{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
@media(max-width:900px){.cards-3,.cards-4{grid-template-columns:1fr 1fr}}
@media(max-width:560px){.cards-3,.cards-4{grid-template-columns:1fr}}
.card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:26px 24px;box-shadow:var(--shadow)}
.card .ic{width:56px;height:56px;border-radius:14px;background:var(--teal-tint);color:var(--teal-d);display:grid;place-items:center;margin-bottom:16px}
.card.mini .ic{width:44px;height:44px;border-radius:12px}
.card h3{font-size:1.12rem;margin-bottom:8px}
.card.mini h3{font-size:1rem}
.card p{color:var(--ink-soft);font-size:.95rem}
.card.mini p{font-size:.88rem}
.ic svg{width:26px;height:26px}

/* ---- testimonials ---- */
.tst-panel{background:var(--teal-tint2);border-radius:22px;padding:40px 28px}
.tst-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-top:26px}
@media(max-width:860px){.tst-grid{grid-template-columns:1fr}}
.tst{display:flex;gap:16px;align-items:flex-start}
.tst-av{width:56px;height:56px;border-radius:50%;flex:0 0 auto;background:linear-gradient(135deg,var(--teal),var(--teal-d));color:#fff;display:grid;place-items:center;font:800 1.2rem Poppins,sans-serif}
.tst .stars{color:var(--gold);font-size:.9rem;letter-spacing:1px}
.tst blockquote{font-size:.95rem;color:var(--ink);margin:4px 0 8px;line-height:1.55}
.tst .hl{color:var(--teal-d);font-weight:800;font-size:.95rem;margin-bottom:6px}
.tst .who{font-size:.85rem;color:var(--ink-soft);display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.tst .badge{border:1px solid var(--teal);color:var(--teal-d);border-radius:999px;padding:2px 10px;font-size:.72rem;font-weight:700}
.tst-note{text-align:center;color:var(--muted);font-size:.8rem;margin-top:18px}

/* ---- pricing ---- */
.price-card{max-width:420px;margin:0 auto;background:#fff;border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow-lg);overflow:hidden;text-align:center}
.price-ribbon{background:var(--teal);color:#fff;font:800 .78rem Poppins,sans-serif;letter-spacing:.1em;padding:9px}
.price-body{padding:30px 34px 34px}
.price-body h3{font-size:1.4rem;margin-bottom:4px}
.price-amt{font:800 3.2rem Poppins,sans-serif;color:var(--teal);line-height:1}
.price-per{color:var(--muted);margin-bottom:20px}
.price-list{list-style:none;text-align:left;display:grid;gap:12px;margin:0 0 24px}
.price-list li{padding-left:30px;position:relative;font-size:.98rem}
.price-list li::before{content:"✓";position:absolute;left:0;top:0;width:20px;height:20px;background:var(--teal-tint);color:var(--teal-d);border-radius:50%;display:grid;place-items:center;font-size:.7rem;font-weight:900}
.price-consent{font-size:.78rem;color:var(--muted);margin-top:14px}

/* ---- see-how (video) ---- */
.demo-frame{max-width:900px;margin:0 auto;background:#0e1c33;border-radius:16px;box-shadow:var(--shadow-lg);overflow:hidden}
.demo-bar{display:flex;gap:6px;padding:11px 14px;border-bottom:1px solid rgba(255,255,255,.08)}
.demo-bar span{width:10px;height:10px;border-radius:50%;background:rgba(255,255,255,.2)}
.demo-frame video{width:100%}
.demo-cap{text-align:center;color:var(--muted);font-size:.86rem;padding:12px}

/* ---- faq ---- */
.faq{max-width:780px;margin:0 auto}
.faq details{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 22px;margin-bottom:10px;box-shadow:var(--shadow)}
.faq summary{font-weight:700;cursor:pointer;font-family:Poppins,sans-serif;color:var(--navy)}
.faq p{margin-top:10px;color:var(--ink-soft);font-size:.95rem}
.faq-cta{max-width:900px;margin:26px auto 0;background:#fff;border:1px solid var(--line);border-radius:16px;padding:20px 26px;display:flex;align-items:center;gap:16px;box-shadow:var(--shadow)}
.faq-cta .q{width:44px;height:44px;border-radius:50%;background:var(--teal-tint);color:var(--teal-d);display:grid;place-items:center;font-weight:800;font-size:1.2rem;flex:0 0 auto}
.faq-cta p{color:var(--ink-soft);flex:1;font-size:.95rem}
@media(max-width:560px){.faq-cta{flex-direction:column;text-align:center}}

/* ---- footer ---- */
.site-footer{background:var(--navy);color:#9fb0c5;padding:52px 0 30px}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr auto;gap:30px;align-items:start}
@media(max-width:820px){.foot-grid{grid-template-columns:1fr 1fr;gap:26px}}
.foot-grid .fcol h4{color:#fff;font-size:.95rem;margin-bottom:12px}
.foot-grid .fcol a{display:block;color:#9fb0c5;margin-bottom:8px;font-size:.9rem}
.foot-grid .fcol a:hover{color:#fff}
.foot-brand img{height:42px;margin-bottom:14px}
.foot-social{display:flex;gap:12px}
.foot-social a{width:34px;height:34px;border-radius:9px;background:rgba(255,255,255,.08);display:grid;place-items:center;color:#cbd6e4}
.foot-social a:hover{background:var(--teal);color:#fff}
.foot-water{opacity:.9}
.foot-water svg{height:80px}
.foot-legal{border-top:1px solid rgba(255,255,255,.1);margin-top:30px;padding-top:20px;text-align:center;font-size:.82rem;color:#6d7f95}
.foot-fine{max-width:52em;margin:8px auto 0;font-size:.75rem;color:#5c6e85}

/* ---- auth modal ---- */
.modal{position:fixed;inset:0;background:rgba(11,31,58,.6);display:grid;place-items:center;z-index:90;padding:18px}
.modal[hidden]{display:none}
.auth-card{background:#fff;border-radius:20px;padding:34px 32px;width:100%;max-width:420px;position:relative}
.auth-close{position:absolute;top:12px;right:16px;background:none;border:0;font-size:1.5rem;color:var(--muted);cursor:pointer}
.auth-title{font-size:1.5rem;margin-bottom:6px}
.auth-sub{color:var(--muted);font-size:.94rem;margin-bottom:20px}
.auth-card label{display:block;font-weight:600;font-size:.9rem;margin-bottom:12px}
.auth-card input{width:100%;padding:12px 14px;border:1.5px solid var(--line);border-radius:10px;font:inherit;margin-top:5px}
.auth-card input:focus{outline:none;border-color:var(--teal)}
.auth-error{color:#c0392b;font-size:.88rem;min-height:1.2em;margin:4px 0 8px}
.auth-toggle{text-align:center;font-size:.9rem;color:var(--muted);margin-top:16px}
.auth-google{display:flex;align-items:center;justify-content:center;gap:10px;width:100%;padding:12px 16px;border:1.5px solid #dadce0;border-radius:10px;background:#fff;color:#3c4043;font-weight:600;font-size:.95rem;text-decoration:none;margin-bottom:6px}
.auth-or{display:flex;align-items:center;gap:12px;color:var(--muted);font-size:.8rem;margin:14px 0}
.auth-or::before,.auth-or::after{content:"";flex:1;height:1px;background:var(--line)}

/* ---- app shell ---- */
.app-header{background:var(--navy)}
.app-header .header-inner{padding:11px 24px}
.app-main{max-width:1180px;margin:0 auto;padding:26px 24px 60px;min-height:calc(100vh - 150px)}
.app-tabs{display:flex;gap:8px;border-bottom:1px solid var(--line);padding-bottom:12px;margin-bottom:24px;flex-wrap:wrap}
.app-tabs button{border:0;background:transparent;font:600 .92rem Inter,sans-serif;color:var(--muted);padding:9px 16px;border-radius:999px;cursor:pointer}
.app-tabs button.on{background:var(--navy);color:#fff}
.app-tabs .spacer{margin-left:auto;display:flex;gap:8px;align-items:center}
.app-title{font-size:clamp(1.5rem,3vw,2.1rem);margin:4px 0 16px}
.paywall{max-width:480px;margin:7vh auto;background:#fff;border:1px solid var(--line);border-radius:22px;padding:40px 36px;text-align:center;box-shadow:var(--shadow)}
.paywall h1{font-size:1.6rem;margin-bottom:8px}.paywall p{color:var(--ink-soft);margin-bottom:10px}
.app-loading{text-align:center;color:var(--muted);padding:70px 0}
.gtee{display:flex;gap:8px;align-items:center;justify-content:center;margin-top:16px;color:var(--ink-soft);font-size:.9rem;font-weight:600}
.consent{font-size:.8rem;color:var(--muted);margin-top:12px}
.toast{position:fixed;bottom:22px;left:50%;transform:translateX(-50%) translateY(20px);background:var(--navy);color:#fff;border-radius:999px;padding:12px 24px;font-size:.92rem;opacity:0;pointer-events:none;transition:all .25s;z-index:99}
.toast.show{opacity:1;transform:translateX(-50%)}
.section-eyebrow{font:700 .78rem Poppins,sans-serif;letter-spacing:.06em;text-transform:uppercase;color:var(--teal-d);margin-bottom:6px}
.prep-loading{color:var(--muted);text-align:center;padding:40px 0}
.cc-fine{color:var(--muted);font-size:.85rem}
.ck-choices{display:grid;gap:8px}
.ck-choice{text-align:left;border:1.5px solid var(--line);background:#fff;border-radius:12px;padding:11px 14px;font:inherit;cursor:pointer}
.ck-choice:hover:not(:disabled){border-color:var(--teal)}
.ck-choice:disabled{opacity:.75;cursor:default}
.ck-choice.ck-right{border-color:#1a7a40;background:#f0faf3;font-weight:700}
.ck-choice.ck-wrong{border-color:#c0392b;background:#fdf3f1}
.dp-how{margin-top:12px;background:none;border:1.5px dashed var(--teal);color:var(--teal-d);font:600 .9rem Inter,sans-serif;border-radius:10px;padding:9px 14px;cursor:pointer;width:100%}
.dp-how:hover{background:var(--teal-tint2)}
.dp-guide{margin-top:14px;background:var(--teal-tint2);border:1px solid rgba(18,179,166,.35);border-radius:14px;padding:16px 18px}
.dp-guide-trick{font:700 .82rem Poppins,sans-serif;color:var(--teal-d);text-transform:uppercase;letter-spacing:.04em;margin-bottom:8px}
.dp-dots{display:flex;gap:6px;margin-bottom:10px}.dp-dots i{width:22px;height:5px;border-radius:999px;background:var(--line)}.dp-dots i.on{background:var(--teal)}
.dp-guide-step{font-size:.95rem;margin-bottom:6px}.dp-guide-watch{font-size:.85rem;color:var(--muted);margin-bottom:12px}.dp-next{margin-top:12px}
.dp-done{display:grid;place-items:center;min-height:50vh}
.dp-done-card{background:#fff;border:1px solid var(--line);border-radius:22px;padding:44px 40px;text-align:center;max-width:460px;box-shadow:var(--shadow)}
.dp-done-emoji{font-size:2.6rem;margin-bottom:10px}.dp-done-card h2{margin-bottom:8px}.dp-done-card p{color:var(--ink-soft)}
.dp-done-actions{display:flex;gap:10px;justify-content:center;margin-top:20px;flex-wrap:wrap}
@media(max-width:820px){.hero-grid{grid-template-columns:1fr;gap:36px}.hero-blob,.dots{display:none}}
/* ---- Desmos playbook ---- */
.dm-note { background: #eef4ff; border: 1px solid #c9d9f5; border-radius: 14px; padding: 14px 18px;
  font-size: .92rem; line-height: 1.6; margin: 0 0 22px; }
.dm-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 16px; margin-bottom: 28px; }
.dm-card { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 20px 22px; box-shadow: var(--shadow);
  display: flex; flex-direction: column; }
.dm-icon { font-size: 1.6rem; }
.dm-card h3 { margin: 8px 0 6px; font-size: 1.05rem; font-family: Poppins, sans-serif; }
.dm-when { font-size: .82rem; color: var(--muted); margin: 0 0 8px; }
.dm-card ol { margin: 0 0 14px; padding-left: 20px; font-size: .88rem; line-height: 1.55; color: var(--ink-soft); }
.dm-card ol li { margin-bottom: 4px; }
.dm-try { margin-top: auto; align-self: flex-start; }
.dm-play-h { margin: 0 0 12px; font-family: Poppins, sans-serif; }
.dm-calc { width: 100%; height: 460px; border: 1px solid var(--line); border-radius: 16px; overflow: hidden;
  box-shadow: var(--shadow); margin-bottom: 10px; background: #fff; }
@media (max-width: 700px) { .dm-calc { height: 380px; } }

/* ---- Desmos practice mode ---- */
.dm-cta { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; margin: 0 0 24px; }
/* Full-bleed: practice mode escapes the page container so the calculator
   can use the whole right side of the screen, digital-ACT style. */
.dp-wrap { display: grid; grid-template-columns: minmax(320px, 400px) 1fr; gap: 18px; align-items: start;
  width: calc(100vw - 40px); position: relative; left: 50%; transform: translateX(-50%); }
.dp-side { position: sticky; top: 12px; }
.dp-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; }
.dp-q { background: #fff; border: 1px solid var(--line); border-radius: 16px; padding: 20px 22px; box-shadow: var(--shadow); }
.dp-stem { font-size: 1.05rem; line-height: 1.55; font-weight: 600; margin: 0 0 14px; }
.dp-choices { max-width: none; margin: 0 0 14px; }
.dp-calc { height: calc(100vh - 90px); min-height: 480px; border: 1px solid var(--line); border-radius: 16px; overflow: hidden; box-shadow: var(--shadow); background: #fff; }
.dp-guide { background: #f2fbf8; border: 1.5px solid #bfe4dd; border-radius: 14px; padding: 14px 16px; margin-top: 12px; }
.dp-guide-trick { margin: 0 0 8px; font: 800 .72rem Inter, sans-serif; text-transform: uppercase; letter-spacing: .05em; color: #116a73; }
.dp-guide-step { margin: 8px 0; font-size: .95rem; line-height: 1.55; }
.dp-guide-watch { margin: 0 0 12px; font-size: .8rem; color: var(--muted); }
.dp-next { margin-top: 12px; }
@media (max-width: 900px) { .dp-wrap { grid-template-columns: 1fr; } .dp-side { position: static; } .dp-calc { height: 420px; } }