:root{
  --ink:#182128;
  --muted:#647078;
  --line:#e5e5df;
  --surface:#f4f1ea;
  --white:#fff;
  --accent:#1d4d4f;
  --accent-2:#315f63;
  --gold:#ad8550;
  --radius:22px;
  --shadow:0 18px 60px rgba(17,32,55,.10);
  --max:1180px;
}
*{box-sizing:border-box}
html{overflow-x:hidden;scroll-behavior:smooth}
body{margin:0;width:100%;overflow-x:hidden;color:var(--ink);background:#fff;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.65}
img{max-width:100%;height:auto;display:block}
a{color:inherit;text-decoration:none}
button,input,select,textarea{font:inherit}
button{cursor:pointer}
.container{width:min(var(--max),calc(100% - 40px));margin:auto}
.skip-link{position:absolute;left:-9999px;top:8px;background:#fff;padding:10px 14px;z-index:1000}
.skip-link:focus{left:8px}
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.92);backdrop-filter:blur(18px);border-bottom:1px solid rgba(231,235,240,.85)}
.nav{height:76px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.wordmark{font-weight:800;letter-spacing:-.045em;font-size:21px;white-space:nowrap}
.wordmark span{font-weight:500;color:var(--muted)}
.nav-links{display:flex;gap:22px;align-items:center;font-size:14px;color:#354154}
.nav-links a:hover{color:var(--accent)}
.nav-cta,.btn{display:inline-flex;align-items:center;justify-content:center;border:0;border-radius:999px;padding:12px 19px;font-weight:750;transition:.2s ease}
.btn-primary{background:var(--ink);color:#fff}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 10px 24px rgba(11,18,32,.16)}
.btn-light{background:#fff;border:1px solid var(--line)}
.btn-accent{background:var(--accent);color:#fff}
.menu-btn{display:none;border:1px solid var(--line);background:#fff;border-radius:12px;padding:9px 11px}
.hero{position:relative;min-height:680px;display:flex;align-items:center;overflow:hidden;background:#eef3f8}
.hero-media{position:absolute;inset:0}
.hero-media img{width:100%;height:100%;object-fit:cover;object-position:center 34%;filter:saturate(.78)}
.hero-overlay{position:absolute;inset:0;background:linear-gradient(90deg,rgba(7,15,27,.84) 0%,rgba(7,15,27,.64) 42%,rgba(7,15,27,.10) 78%),linear-gradient(0deg,rgba(7,15,27,.18),rgba(7,15,27,.04))}
.hero-content{position:relative;color:#fff;max-width:700px;padding:100px 0}
.eyebrow{font-size:12px;text-transform:uppercase;letter-spacing:.16em;font-weight:800;opacity:.78}
.hero h1{font-size:clamp(44px,7vw,78px);line-height:1.04;letter-spacing:-.055em;margin:18px 0 22px}
.hero p{font-size:19px;max-width:640px;color:rgba(255,255,255,.87);margin:0 0 30px}
.actions{display:flex;gap:12px;flex-wrap:wrap}
.hero .btn-light{background:rgba(255,255,255,.12);color:#fff;border-color:rgba(255,255,255,.35);backdrop-filter:blur(8px)}
.section{padding:96px 0}
.section-sm{padding:62px 0}
.section-muted{background:var(--surface)}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:24px;margin-bottom:34px}
.section-head h2{font-size:clamp(30px,4vw,48px);line-height:1.12;letter-spacing:-.045em;margin:0}
.section-head p{max-width:560px;color:var(--muted);margin:0}
.grid{display:grid;gap:18px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.card{border:1px solid var(--line);border-radius:var(--radius);padding:26px;background:#fff}
.card:hover{box-shadow:var(--shadow);transform:translateY(-2px);transition:.2s ease}
.card h3{margin:0 0 8px;font-size:20px;letter-spacing:-.025em}
.card p{margin:0;color:var(--muted)}
.card .tag{display:inline-block;margin-bottom:16px;font-size:12px;font-weight:800;color:var(--accent);background:#edf3fb;padding:6px 9px;border-radius:999px}
.exam-card{min-height:190px;display:flex;flex-direction:column;justify-content:space-between}
.exam-card .arrow{font-size:22px;color:var(--accent)}
.kicker{color:var(--accent);font-weight:800;font-size:13px;letter-spacing:.04em}
.split{display:grid;grid-template-columns:1fr 1fr;gap:50px;align-items:center}
.split img{border-radius:28px;box-shadow:var(--shadow);width:100%;aspect-ratio:4/3;object-fit:cover}
.split h2{font-size:clamp(32px,4vw,52px);line-height:1.1;letter-spacing:-.045em;margin:12px 0 18px}
.list{padding:0;margin:22px 0 0;list-style:none}
.list li{padding:12px 0;border-bottom:1px solid var(--line)}
.list li:last-child{border-bottom:0}
.stat-row{display:grid;grid-template-columns:repeat(4,1fr);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.stat{padding:28px 20px;border-right:1px solid var(--line)}
.stat:last-child{border-right:0}
.stat strong{display:block;font-size:28px;letter-spacing:-.04em}
.stat span{color:var(--muted);font-size:14px}
.breadcrumb{padding:28px 0 0;color:var(--muted);font-size:13px}
.page-hero{padding:74px 0 70px;background:linear-gradient(180deg,#f4f7fb,#fff)}
.page-hero h1{font-size:clamp(42px,6vw,70px);line-height:1.04;letter-spacing:-.055em;margin:10px 0 18px}
.page-hero p{max-width:740px;color:var(--muted);font-size:18px}
.notice{padding:16px 18px;border-radius:14px;background:#f4f7fb;border:1px solid var(--line);font-size:14px;color:#485466}
.pill-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:22px}
.pill{border:1px solid var(--line);padding:8px 11px;border-radius:999px;font-size:13px;background:#fff}
.timeline{display:grid;gap:14px}
.timeline-item{display:grid;grid-template-columns:80px 1fr;gap:18px;border-bottom:1px solid var(--line);padding:18px 0}
.timeline-item strong{color:var(--accent)}
.diagnostic{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.score{background:var(--ink);color:#fff;border-radius:24px;padding:30px}
.score .big{font-size:52px;font-weight:800;line-height:1}
.score small{opacity:.7}
.progress{height:10px;background:#dfe5ee;border-radius:999px;overflow:hidden;margin-top:15px}
.progress i{display:block;height:100%;background:#7ca0cf;width:62%}
.skill{padding:15px 0;border-bottom:1px solid rgba(255,255,255,.13)}
.skill:last-child{border:0}
.form{display:grid;gap:16px}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
label{display:grid;gap:7px;font-size:14px;font-weight:700}
input,select,textarea{width:100%;border:1px solid #d8dee8;border-radius:12px;padding:12px 13px;background:#fff;color:var(--ink);outline:none}
input:focus,select:focus,textarea:focus{border-color:#7896bd;box-shadow:0 0 0 3px rgba(71,111,162,.12)}
textarea{min-height:130px;resize:vertical}
.form-note{font-size:12px;color:var(--muted)}
.alert{padding:13px 15px;border-radius:12px;background:#f6f8fb;border:1px solid var(--line);font-size:14px}
.cta{background:var(--ink);color:#fff;border-radius:30px;padding:52px}
.cta h2{font-size:clamp(30px,4vw,46px);letter-spacing:-.045em;line-height:1.12;margin:0 0 12px}
.cta p{color:rgba(255,255,255,.72);max-width:650px}
.footer{background:#0b1220;color:#fff;padding:60px 0 30px}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:30px}
.footer a{color:rgba(255,255,255,.7);font-size:14px}
.footer a:hover{color:#fff}
.footer h4{margin:0 0 13px;font-size:13px}
.footer p{color:rgba(255,255,255,.58);font-size:14px;max-width:440px}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1);margin-top:38px;padding-top:20px;color:rgba(255,255,255,.48);font-size:12px;display:flex;justify-content:space-between;gap:20px}
.faq details{border-bottom:1px solid var(--line);padding:18px 0}
.faq summary{cursor:pointer;font-weight:750}
.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:18px}
table{border-collapse:collapse;width:100%;min-width:680px}
th,td{text-align:left;padding:14px 16px;border-bottom:1px solid var(--line);font-size:14px}
th{background:#f7f9fc}
.admin-shell{min-height:100vh;background:#f6f8fb}
.admin-nav{background:#0b1220;color:#fff;padding:18px 0}
.admin-main{padding:35px 0}
.admin-cards{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.admin-card{background:#fff;border:1px solid var(--line);border-radius:16px;padding:20px}
.admin-card strong{font-size:30px;display:block}
.hidden{display:none!important}
.small{font-size:12px;color:var(--muted)}
.center{text-align:center}
@media(max-width:980px){
  .nav-links{display:none;position:absolute;top:76px;left:0;right:0;background:#fff;padding:18px 20px;border-bottom:1px solid var(--line);flex-direction:column;align-items:stretch}
  .nav-links.open{display:flex}
  .menu-btn{display:block}
  .nav-cta{display:none}
  .grid-4{grid-template-columns:repeat(2,1fr)}
  .grid-3{grid-template-columns:1fr 1fr}
  .split{grid-template-columns:1fr}
  .stat-row{grid-template-columns:1fr 1fr}
  .stat:nth-child(2){border-right:0}
  .stat:nth-child(1),.stat:nth-child(2){border-bottom:1px solid var(--line)}
  .footer-grid{grid-template-columns:1fr 1fr}
  .admin-cards{grid-template-columns:1fr 1fr}
}
@media(max-width:640px){
  .container{width:min(var(--max),calc(100% - 28px))}
  .nav{height:68px}
  .nav-links{top:68px}
  .hero{min-height:620px}
  .hero-content{padding:78px 0}
  .hero h1{font-size:47px}
  .hero p{font-size:16px}
  .section{padding:68px 0}
  .section-head{display:block}
  .section-head p{margin-top:14px}
  .grid-3,.grid-4{grid-template-columns:1fr}
  .form-grid{grid-template-columns:1fr}
  .diagnostic{grid-template-columns:1fr}
  .stat-row{grid-template-columns:1fr}
  .stat{border-right:0!important;border-bottom:1px solid var(--line)}
  .stat:last-child{border-bottom:0}
  .footer-grid{grid-template-columns:1fr}
  .footer-bottom{display:block}
  .cta{padding:34px 24px}
  .timeline-item{grid-template-columns:60px 1fr}
}

.exam-facts{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:26px}
.exam-fact{padding:22px;border:1px solid var(--line);border-radius:18px;background:#fff}
.exam-fact strong{display:block;font-size:26px;letter-spacing:-.04em;margin-top:4px}
.exam-fact span{display:block;color:var(--muted);font-size:13px;margin-top:3px}
.source-note{margin-top:18px;color:var(--muted);font-size:12px}
.material-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.material-card{display:flex;flex-direction:column;min-height:190px}
.material-card .material-title{font-size:17px;font-weight:800;line-height:1.35;margin:4px 0 10px}
.material-card .material-meta{font-size:12px;color:var(--muted);margin-top:auto;padding-top:18px}
.material-card .btn{margin-top:16px;width:max-content}
.contact-priority{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:24px}
.contact-priority .card{display:flex;align-items:center;justify-content:space-between;gap:18px}
.contact-priority .big-contact{font-size:26px;font-weight:850;letter-spacing:-.03em}
.sticky-contact{position:fixed;left:14px;right:14px;bottom:14px;z-index:80;display:none;grid-template-columns:1fr 1fr;gap:8px;padding:8px;background:rgba(11,18,32,.94);border:1px solid rgba(255,255,255,.12);border-radius:18px;box-shadow:0 18px 50px rgba(0,0,0,.22);backdrop-filter:blur(12px)}
.sticky-contact a{display:flex;align-items:center;justify-content:center;min-height:46px;border-radius:12px;font-weight:800;font-size:14px}
.sticky-contact .phone{background:#fff;color:var(--ink)}
.sticky-contact .kakao{background:#f5d54f;color:#111}
@media(max-width:980px){.exam-facts{grid-template-columns:1fr 1fr}.material-grid{grid-template-columns:1fr 1fr}.sticky-contact{display:grid}}
@media(max-width:640px){.exam-facts{grid-template-columns:1fr 1fr}.material-grid{grid-template-columns:1fr}.contact-priority{grid-template-columns:1fr}.exam-fact strong{font-size:22px}}


/* Responsive hardening */
html{overflow-x:hidden}
body{overflow-x:hidden}
img,video,svg{max-width:100%;height:auto}
button,a{touch-action:manipulation}
@media(min-width:981px){.menu-btn{display:none!important}.nav-links{display:flex!important}}
@media(max-width:980px){.nav{gap:12px}.wordmark{font-size:18px}.nav-links a{padding:10px 0}.hero-media img{object-position:center center}.table-wrap{max-width:100%}}
@media(max-width:640px){.container{width:min(var(--max),calc(100% - 28px))}.wordmark{font-size:17px}.hero{min-height:600px}.hero-content{padding:70px 0 100px}.hero h1{font-size:clamp(38px,11vw,48px)}.hero p{font-size:16px;line-height:1.7}.btn{min-height:46px}.actions .btn{flex:1 1 100%}.card{padding:22px}.exam-facts{grid-template-columns:1fr 1fr!important}.exam-fact{padding:17px}.exam-fact strong{font-size:20px}.sticky-contact{left:10px;right:10px;bottom:10px}}
@media(max-width:390px){.exam-facts{grid-template-columns:1fr!important}.nav{height:64px}.nav-links{top:64px}.hero h1{font-size:38px}}


/* AP CALCULUS FOCUSED REDESIGN — 2026 */
:root{
  --ap-cream:#f7f4ed;
  --ap-soft:#eef3f0;
  --ap-teal:#1d4d4f;
  --ap-deep:#183b3d;
  --ap-gold:#ad8550;
}
.site-header{background:rgba(250,249,246,.94);border-bottom-color:rgba(24,33,40,.08)}
.wordmark{color:var(--ink)}
.wordmark span{color:var(--ap-teal)}
.nav-links{gap:18px}
.nav-links a:nth-child(1),.nav-links a:nth-child(2){font-weight:800;color:var(--ap-teal)}
.btn-primary{background:var(--ap-teal)}
.btn-primary:hover{box-shadow:0 10px 24px rgba(29,77,79,.18)}
.btn-accent{background:var(--ap-teal)}
.kicker{color:var(--ap-teal)}
.section-muted{background:var(--ap-cream)}
.card .tag{color:var(--ap-teal);background:#e8efeb}
.page-hero{background:linear-gradient(180deg,#f7f4ed,#fff)}
.page-hero .kicker{color:var(--ap-teal)}
.ap-home-hero{
  background:linear-gradient(120deg,#f7f4ed 0%,#eef3f0 58%,#fff 100%);
  min-height:690px;
  display:flex;
  align-items:center;
  padding:72px 0;
}
.ap-home-hero-grid{
  display:grid;
  grid-template-columns:1.02fr .98fr;
  gap:58px;
  align-items:center;
}
.ap-home-copy{max-width:680px}
.ap-home-copy .eyebrow{color:var(--ap-teal);opacity:1}
.ap-home-copy h1{
  font-size:clamp(46px,6vw,76px);
  line-height:1.03;
  letter-spacing:-.06em;
  margin:18px 0 22px;
}
.ap-home-copy h1 em{font-style:normal;color:var(--ap-teal)}
.ap-home-copy p{font-size:19px;color:#566168;max-width:620px;margin:0 0 30px}
.ap-hero-note{
  display:flex;gap:12px;flex-wrap:wrap;margin-top:26px;
}
.ap-hero-note span{
  border:1px solid rgba(29,77,79,.15);
  background:rgba(255,255,255,.62);
  padding:8px 12px;border-radius:999px;
  font-size:12px;font-weight:800;color:#38575a;
}
.ap-hero-photo{
  position:relative;
}
.ap-hero-photo img{
  width:100%;aspect-ratio:4/3;object-fit:cover;
  border-radius:30px;
  box-shadow:0 28px 70px rgba(24,33,40,.15);
}
.ap-hero-photo:after{
  content:"AP CALCULUS · 1:1 / SMALL GROUP";
  position:absolute;left:22px;bottom:22px;
  padding:10px 13px;border-radius:999px;
  background:rgba(24,59,61,.9);color:#fff;
  font-size:11px;font-weight:800;letter-spacing:.08em;
}
.ap-feature{
  background:#fff;
  border:1px solid var(--line);
  border-radius:28px;
  overflow:hidden;
  display:grid;
  grid-template-columns:1.05fr .95fr;
  box-shadow:0 18px 55px rgba(24,33,40,.07);
}
.ap-feature-media img{width:100%;height:100%;min-height:340px;object-fit:cover}
.ap-feature-copy{padding:42px}
.ap-feature-copy h3{font-size:clamp(27px,3vw,40px);line-height:1.12;letter-spacing:-.045em;margin:12px 0 16px}
.ap-feature-copy p{color:var(--muted)}
.ap-feature-copy .meta{font-size:12px;font-weight:800;color:var(--ap-gold);letter-spacing:.08em}
.ap-blog-card{position:relative;display:flex;flex-direction:column;min-height:230px}
.ap-blog-card h3{font-size:21px;line-height:1.25;margin:10px 0}
.ap-blog-card p{font-size:14px}
.ap-blog-card .read{margin-top:auto;padding-top:22px;font-weight:800;color:var(--ap-teal);font-size:13px}
.ap-rail{
  display:flex;gap:10px;flex-wrap:wrap;margin-top:20px;
}
.ap-rail a{
  padding:9px 13px;border-radius:999px;
  background:#fff;border:1px solid var(--line);
  font-size:13px;font-weight:750;
}
.ap-rail a:hover{border-color:var(--ap-teal);color:var(--ap-teal)}
.ap-article{max-width:860px;margin:0 auto}
.ap-article h2{font-size:clamp(29px,4vw,44px);line-height:1.15;letter-spacing:-.045em;margin:54px 0 18px}
.ap-article h3{font-size:22px;margin:34px 0 10px}
.ap-article p{font-size:16px;color:#4e5a61}
.ap-article ul{padding-left:20px;color:#4e5a61}
.ap-article li{margin:9px 0}
.ap-article-hero{width:100%;aspect-ratio:16/7;object-fit:cover;border-radius:28px;margin:28px 0 40px}
.ap-quote{
  margin:32px 0;padding:26px 28px;border-left:4px solid var(--ap-gold);
  background:var(--ap-cream);border-radius:0 18px 18px 0;
  font-size:20px;line-height:1.5;font-weight:750;color:var(--ink);
}
.ap-table{margin:28px 0}
.ap-table table{min-width:720px}
.ap-cta-band{
  background:var(--ap-deep);color:#fff;border-radius:30px;padding:48px;
}
.ap-cta-band h2{font-size:clamp(30px,4vw,48px);line-height:1.1;margin:0 0 12px;letter-spacing:-.05em}
.ap-cta-band p{color:rgba(255,255,255,.72);max-width:680px}
.ap-badge{display:inline-flex;align-items:center;gap:7px;font-size:11px;font-weight:900;letter-spacing:.1em;color:var(--ap-teal);background:#e8efeb;padding:7px 10px;border-radius:999px}
.ap-page-nav{
  background:#fff;border-top:1px solid var(--line);border-bottom:1px solid var(--line);
}
.ap-page-nav .container{display:flex;gap:22px;overflow:auto;white-space:nowrap}
.ap-page-nav a{padding:14px 2px;font-size:13px;font-weight:800;color:#667177}
.ap-page-nav a:hover{color:var(--ap-teal)}
.site-header .nav-cta{background:var(--ap-teal)}
.footer .wordmark{color:#fff}
.footer .wordmark span{color:#b9cecc}
@media(max-width:900px){
  .ap-home-hero{padding:56px 0;min-height:auto}
  .ap-home-hero-grid,.ap-feature{grid-template-columns:1fr}
  .ap-hero-copy{order:1}
  .ap-hero-photo{order:2}
  .ap-feature-copy{padding:32px}
  .ap-feature-media img{min-height:250px;max-height:420px}
}
@media(max-width:640px){
  .ap-home-copy h1{font-size:clamp(40px,12vw,52px)}
  .ap-home-copy p{font-size:16px}
  .ap-hero-photo img{border-radius:22px}
  .ap-feature{border-radius:22px}
  .ap-feature-copy{padding:26px}
  .ap-cta-band{padding:32px 24px;border-radius:24px}
}