/* ===========================================================
   DIVE MARU — landing page
   =========================================================== */
:root{
  --accent:#00a2dd;
  --accent-d:#0089bd;
  --ink:#121417;
  --ink-2:#3d454c;
  --mid:#727a82;
  --line:#e2e5e8;
  --gray:#f4f5f6;
  --dark:#23262a;
  --deep:#0e2433;
  --max:1280px;
  --hd:84px;
}
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:var(--hd)}
body{
  margin:0;background:#fff;color:var(--ink);
  font-family:"Pretendard Variable",Pretendard,-apple-system,BlinkMacSystemFont,"Apple SD Gothic Neo","Malgun Gothic",system-ui,sans-serif;
  font-size:16px;line-height:1.75;letter-spacing:-.01em;
  word-break:keep-all;overflow-wrap:break-word;
}
body.is-locked{overflow:hidden}
h1,h2,h3{margin:0;line-height:1.24;letter-spacing:-.035em;font-weight:800}
p{margin:0}
ul,ol,dl,dd{margin:0;padding:0;list-style:none}
a{color:inherit;text-decoration:none}
img{display:block;width:100%;height:100%;object-fit:cover}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
.wrap{width:100%;max-width:var(--max);margin-inline:auto;padding-inline:28px}
.skip{position:absolute;left:-9999px}
.skip:focus{left:14px;top:14px;z-index:200;background:#fff;padding:10px 16px;border:1px solid var(--ink)}

/* ---------------- buttons ---------------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  height:56px;padding:0 34px;font-size:16px;font-weight:700;letter-spacing:-.01em;
  border:1px solid transparent;transition:background .18s,color .18s,border-color .18s;
}
.btn--accent{background:var(--accent);color:#fff}
.btn--accent:hover{background:var(--accent-d)}
.btn--line{background:transparent;color:#fff;border-color:rgba(255,255,255,.55)}
.btn--line:hover{background:#fff;color:var(--ink);border-color:#fff}
.btn--ghost{background:rgba(255,255,255,.06);color:#fff;border-color:rgba(255,255,255,.4)}
.btn--ghost:hover{background:rgba(255,255,255,.16)}
.btn--sm{height:42px;padding:0 20px;font-size:14.5px}
.btn--lg{height:60px;padding:0 40px}
.btn--shadow{position:relative;margin-top:36px;box-shadow:9px 9px 0 rgba(18,20,23,.13)}
.btn--shadow:hover{box-shadow:5px 5px 0 rgba(18,20,23,.13)}
.alink{
  display:inline-flex;align-items:center;gap:8px;margin-top:20px;
  font-weight:700;font-size:15px;color:var(--accent);
  border-bottom:1px solid currentColor;padding-bottom:2px;
}
.alink::after{content:"→";font-weight:400}

/* ---------------- header ---------------- */
.hd{position:fixed;top:0;left:0;right:0;z-index:90;background:#fff;border-bottom:1px solid var(--line)}
.hd__in{display:flex;align-items:center;gap:30px;height:var(--hd);max-width:var(--max);margin-inline:auto;padding-inline:28px}
.logo{display:flex;align-items:center;gap:11px;color:var(--accent);margin-right:auto}
.logo__mark{width:40px;height:40px;flex:none}
.logo__txt{display:flex;flex-direction:column;line-height:1.05;color:var(--ink)}
.logo__txt b{font-size:21px;font-weight:800;letter-spacing:-.04em}
.logo__txt em{font-style:normal;font-size:10px;font-weight:700;letter-spacing:.26em;color:var(--mid);margin-top:3px}
.gnb{display:flex;gap:38px}
.gnb a{font-size:17px;font-weight:600;color:var(--ink-2);position:relative;padding:6px 0}
.gnb a::after{content:"";position:absolute;left:0;right:100%;bottom:0;height:2px;background:var(--accent);transition:right .25s}
.gnb a:hover{color:var(--ink)}
.gnb a:hover::after{right:0}
.hd__side{display:flex;align-items:center;gap:16px}
.ham{display:none;width:34px;height:26px;flex-direction:column;justify-content:space-between}
.ham span{display:block;height:3px;background:var(--ink);transition:transform .25s,opacity .2s}
.ham[aria-expanded="true"] span:nth-child(1){transform:translateY(11.5px) rotate(45deg)}
.ham[aria-expanded="true"] span:nth-child(2){opacity:0}
.ham[aria-expanded="true"] span:nth-child(3){transform:translateY(-11.5px) rotate(-45deg)}

/* mobile nav */
.mnav{position:fixed;inset:var(--hd) 0 0;z-index:80;background:#fff;overflow-y:auto}
.mnav nav{display:flex;flex-direction:column}
.mnav a{display:flex;align-items:baseline;gap:14px;padding:24px 28px;border-bottom:1px solid var(--line);font-size:23px;font-weight:800;letter-spacing:-.03em}
.mnav a em{font-style:normal;font-size:11px;font-weight:700;letter-spacing:.2em;color:var(--mid)}

/* side rail */
.rail{position:fixed;right:0;top:52%;z-index:70;display:flex;flex-direction:column;gap:1px}
.rail a{display:grid;place-items:center;width:46px;height:46px;background:rgba(18,20,23,.55);color:#fff;transition:background .18s}
.rail a:hover{background:var(--accent)}
.rail svg{width:21px;height:21px}

/* ---------------- photo slots ---------------- */
.photo{position:relative;overflow:hidden;background:var(--deep)}
.photo::after{
  content:"";position:absolute;inset:0;opacity:0;
  background:repeating-linear-gradient(-45deg,rgba(255,255,255,.045) 0 1px,transparent 1px 11px);
}
.photo.is-empty::after{opacity:1}
.photo__ph{position:absolute;inset:0;display:none;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 44 44'%3E%3Cg fill='none' stroke='%23ffffff' stroke-width='2.4' stroke-linecap='round' opacity='0.16'%3E%3Ccircle cx='22' cy='22' r='20'/%3E%3Cpath d='M8 27c3.4 0 5.1-3.4 8.5-3.4S22 27 25.4 27s5.1-3.4 8.5-3.4'/%3E%3Cpath d='M15 10c7.5 0 13 4.6 15 11'/%3E%3C/g%3E%3C/svg%3E");background-repeat:no-repeat;background-position:center;background-size:64px}
.photo.is-empty .photo__ph{display:block}
.photo--4x3{aspect-ratio:4/3}
.photo--4x5{aspect-ratio:4/5}

/* ---------------- hero ---------------- */
.hero{position:relative;margin-top:var(--hd);height:clamp(560px,84vh,860px);color:#fff;overflow:hidden}
.photo--hero{position:absolute;inset:0}
.photo--hero::before{
  content:"";position:absolute;inset:0;z-index:2;
  background:linear-gradient(90deg,rgba(6,18,28,.78),rgba(6,18,28,.42) 55%,rgba(6,18,28,.24));
}
.hero__body{position:relative;z-index:3;max-width:var(--max);margin-inline:auto;padding:0 28px;height:100%;display:flex;flex-direction:column;justify-content:center}
.hero__tag{font-size:13px;font-weight:800;letter-spacing:.3em;color:#fff;opacity:.85;margin-bottom:22px}
.hero__tag::before{content:"";display:inline-block;width:26px;height:2px;background:var(--accent);vertical-align:middle;margin-right:12px}
.hero__h{font-size:clamp(2.15rem,5.6vw,4.35rem);font-weight:800;letter-spacing:-.045em;line-height:1.16;text-wrap:balance}
.hero__h span{color:#fff;position:relative;display:inline-block}
.hero__h span::after{content:"";position:absolute;left:0;right:0;bottom:-.08em;height:5px;background:var(--accent)}
.hero__p{margin-top:30px;max-width:620px;font-size:clamp(1rem,1.4vw,1.14rem);color:rgba(255,255,255,.86);line-height:1.75;text-wrap:pretty}
.hero__btns{display:flex;flex-wrap:wrap;gap:10px;margin-top:40px}
.nb{white-space:nowrap}
.hero__scroll{position:absolute;left:50%;bottom:32px;z-index:3;transform:translateX(-50%);display:flex;flex-direction:column;align-items:center;gap:10px;color:rgba(255,255,255,.85);font-size:11px;font-weight:700;letter-spacing:.28em}
.hero__scroll svg{width:12px;height:26px;animation:bob 1.9s ease-in-out infinite}
@keyframes bob{0%,100%{transform:translateY(0);opacity:.5}50%{transform:translateY(7px);opacity:1}}
@media (prefers-reduced-motion:reduce){.hero__scroll svg{animation:none}}

/* ---------------- intro strip ---------------- */
.strip{border-bottom:1px solid var(--line)}
.strip__grid{display:grid;grid-template-columns:repeat(3,1fr)}
.strip__it{padding:56px 40px 56px 0;border-right:1px solid var(--line)}
.strip__it:last-child{border-right:0;padding-right:0}
.strip__it+.strip__it{padding-left:40px}
.strip__no{font-size:12px;font-weight:800;letter-spacing:.22em;color:var(--accent);margin-bottom:14px}
.strip__it h2{font-size:1.24rem;margin-bottom:10px}
.strip__it p{font-size:15.5px;color:var(--mid);line-height:1.7;text-wrap:pretty}

/* ---------------- section shell ---------------- */
.sec{padding:118px 0}
.sec--gray{background:var(--gray)}
.sec--dark{background:var(--dark);color:#fff}
.shead{text-align:center;margin-bottom:64px}
.shead h2{font-size:clamp(2.3rem,5.6vw,4rem);font-weight:900;letter-spacing:-.04em;line-height:1}
.shead p{margin-top:20px;font-size:clamp(.98rem,1.4vw,1.08rem);color:var(--mid);text-wrap:balance}
.sec--dark .shead p{color:rgba(255,255,255,.66)}
.sec__note{margin-top:44px;text-align:center;font-size:14.5px;color:var(--mid)}

/* ---------------- courses ---------------- */
.crs{display:grid;grid-template-columns:repeat(4,1fr);gap:26px}
.crs__it{display:flex;flex-direction:column;background:#fff}
.crs__it .photo{aspect-ratio:3/4}
.crs__it .photo img{transition:transform .5s ease}
.crs__it:hover .photo img{transform:scale(1.045)}
.crs__cap{padding-top:22px}
.crs__cap h3{font-size:1.3rem;font-weight:800;letter-spacing:-.03em}
.crs__cap p{margin-top:5px;font-size:14.5px;font-weight:600;color:var(--accent)}
.crs__body{padding-top:12px}
.crs__body p{font-size:15px;color:var(--mid);line-height:1.72}

/* ---------------- split sections ---------------- */
.split{display:grid;grid-template-columns:1.04fr .96fr;gap:76px;align-items:center}
.split--rev .split__txt{order:-1}
.big{font-size:clamp(2.2rem,4.8vw,3.5rem);font-weight:900;letter-spacing:-.045em;line-height:1.05}
.lead{margin-top:26px;font-size:clamp(1.12rem,1.9vw,1.42rem);font-weight:800;letter-spacing:-.03em}
.split__txt p+p{margin-top:16px}
.split__txt>p:not(.name){text-wrap:pretty}
.split__txt>p:not(.lead):not(.name){color:var(--mid);font-size:16px;line-height:1.8}
.sec--dark .split__txt>p:not(.lead):not(.name){color:rgba(255,255,255,.7)}
.name{margin-top:30px;font-size:1.7rem;font-weight:800;letter-spacing:-.035em}
.name em{font-style:normal;font-size:13px;font-weight:700;letter-spacing:.06em;color:var(--accent);margin-left:12px}
.creds{margin-top:26px;border-top:1px solid rgba(255,255,255,.16)}
.creds li{display:flex;flex-wrap:wrap;gap:4px 16px;align-items:baseline;padding:15px 0;border-bottom:1px solid rgba(255,255,255,.16)}
.creds b{font-size:16px;font-weight:700}
.creds span{font-size:14px;color:rgba(255,255,255,.55)}

/* ---------------- flow ---------------- */
.flow{display:grid;grid-template-columns:repeat(4,1fr);gap:0}
.flow li{padding:36px 30px 0 0;border-top:2px solid var(--ink)}
.flow li+li{padding-left:30px;border-left:1px solid var(--line)}
.flow span{display:block;font-size:13px;font-weight:800;letter-spacing:.2em;color:var(--accent);margin-bottom:16px}
.flow h3{font-size:1.16rem;margin-bottom:10px}
.flow p{font-size:15px;color:var(--mid);line-height:1.72;text-wrap:pretty}

/* ---------------- contact band ---------------- */
.band{position:relative;overflow:hidden;color:#fff}
.photo--band{position:absolute;inset:0}
.photo--band::before{content:"";position:absolute;inset:0;z-index:2;background:linear-gradient(90deg,rgba(10,14,18,.9),rgba(10,14,18,.55))}
.band__in{position:relative;z-index:3;padding-block:110px}
.band__h{font-size:clamp(1.25rem,2.5vw,1.95rem);font-weight:800;letter-spacing:-.035em;line-height:1.55;text-wrap:balance}
.band__btns{display:flex;flex-wrap:wrap;gap:10px;margin-top:38px}

/* ---------------- location ---------------- */
.loc{display:grid;grid-template-columns:repeat(2,1fr);gap:0;border-top:2px solid var(--ink)}
.loc article{padding:44px 48px 44px 0}
.loc article+article{padding-left:48px;border-left:1px solid var(--line)}
.loc__lb{font-size:13px;font-weight:800;letter-spacing:.1em;color:var(--accent);margin-bottom:14px}
.loc h3{font-size:1.32rem;margin-bottom:12px}
.loc p{font-size:15.5px;color:var(--mid);line-height:1.72}

/* ---------------- footer ---------------- */
.ft{background:var(--dark);color:rgba(255,255,255,.62);padding:64px 0 56px;font-size:14.5px}
.ft__in{display:flex;justify-content:space-between;gap:44px;flex-wrap:wrap}
.ft__mark{width:56px;height:56px;color:rgba(255,255,255,.5)}
.ft__cr{margin-top:20px;font-size:12.5px;letter-spacing:.06em;color:rgba(255,255,255,.4);line-height:1.6}
.ft__biz{margin-top:26px;display:grid;gap:7px}
.ft__biz div{display:flex;gap:7px}
.ft__biz dt{color:rgba(255,255,255,.42);white-space:nowrap}
.ft__biz dt::after{content:" ·"}
.ft__biz dd{color:rgba(255,255,255,.82)}
.ft__r{display:flex;flex-direction:column;align-items:flex-end;gap:34px}
.ft__sns{display:flex;gap:10px}
.ft__sns a{display:grid;place-items:center;width:42px;height:42px;border:1px solid rgba(255,255,255,.22);color:#fff;transition:background .18s,border-color .18s}
.ft__sns a:hover{background:var(--accent);border-color:var(--accent)}
.ft__sns svg{width:20px;height:20px}
.ft__nav{display:flex;flex-wrap:wrap;gap:0 22px;justify-content:flex-end}
.ft__nav a{position:relative;font-size:14.5px;color:rgba(255,255,255,.7)}
.ft__nav a:hover{color:#fff}
.ft__nav a+a::before{content:"";position:absolute;left:-11px;top:50%;width:1px;height:12px;transform:translateY(-50%);background:rgba(255,255,255,.2)}

/* ===========================================================
   responsive
   =========================================================== */
@media (max-width:1120px){
  .crs{grid-template-columns:repeat(2,1fr);gap:30px}
  .split{gap:48px}
  .flow{grid-template-columns:repeat(2,1fr);row-gap:34px}
  .flow li:nth-child(3){padding-left:0;border-left:0}
}
@media (max-width:900px){
  :root{--hd:68px}
  .gnb{display:none}
  .ham{display:flex}
  .rail{display:none}
  .sec{padding:78px 0}
  .shead{margin-bottom:46px;text-align:left}
  .strip__grid{grid-template-columns:1fr}
  .strip__it,.strip__it+.strip__it{padding:32px 0;border-right:0;border-bottom:1px solid var(--line)}
  .strip__it:last-child{border-bottom:0}
  .split{grid-template-columns:1fr;gap:40px}
  .split--rev .split__txt{order:0}
  .loc{grid-template-columns:1fr}
  .loc article,.loc article+article{padding:34px 0;border-left:0;border-bottom:1px solid var(--line)}
  .loc article:last-child{border-bottom:0}
  .band__in{padding-block:78px}
  .ft__in{flex-direction:column}
  .ft__r{align-items:flex-start;gap:24px}
  .ft__nav{justify-content:flex-start}
}
@media (max-width:600px){
  .wrap,.hd__in,.hero__body{padding-inline:20px}
  .hd__side .btn{display:none}
  .hero__scroll{display:none}
  .hero{height:auto;min-height:auto;padding:86px 0 96px}
  .photo--hero{position:absolute}
  .hero__body{height:auto}
  .hero__btns .btn{flex:1 1 100%}
  .crs{grid-template-columns:1fr;gap:34px}
  .flow{grid-template-columns:1fr;row-gap:28px}
  .flow li,.flow li+li{padding:28px 0 0;border-left:0}
  .band__btns .btn{flex:1 1 100%}
  .ft__biz div{flex-direction:column;gap:2px}
  .ft__biz dt::after{content:""}
}