:root{
  --navy:#1E2B4A; --navy2:#2A3A60; --gold:#C9A66B; --gold-d:#A8864C;
  --ivory:#F8F5EF; --paper:#FFFFFF; --ink:#1E2B4A; --ink2:#4A5468; --line:#E3DCCF;
  --ok:#2F6B4F; --ok-bg:#E8F2EC; --ng:#A23B3B; --ng-bg:#F8E9E7;
  --serif:"Noto Serif KR","Noto Serif CJK KR","Nanum Myeongjo","AppleMyungjo",serif;
  --sans:"Noto Sans KR","Noto Sans CJK KR","Apple SD Gothic Neo","Malgun Gothic",system-ui,sans-serif;
  --gut:16px; --max:720px; --r:14px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--ivory);color:var(--ink);font-family:var(--sans);font-size:16px;line-height:1.65;
  word-break:keep-all;overflow-wrap:anywhere;overflow-x:hidden}
img{max-width:100%;display:block}
a{color:inherit}
h1,h2,h3{font-family:var(--serif);font-weight:700;line-height:1.35;margin:0}
p{margin:0}
.wrap{max-width:var(--max);margin:0 auto;padding:0 var(--gut)}
.serif{font-family:var(--serif)}
.gold{color:var(--gold)}
.sub{color:var(--ink2)}
.small{font-size:14px;color:var(--ink2)}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}

/* header */
.top{background:var(--navy);color:var(--ivory)}
.top .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;height:56px}
.top .brand{display:flex;align-items:center;gap:10px;text-decoration:none;min-width:0}
.top .brand img{height:20px;width:auto}
.top .brand span{font-size:13px;color:var(--gold);white-space:nowrap;letter-spacing:.5px}
.top nav{display:flex;gap:14px;font-size:14px;flex-shrink:0}
.top nav a{text-decoration:none;opacity:.9}
.top nav a:hover{opacity:1;color:var(--gold)}

/* hero */
.hero{background:var(--navy);color:var(--ivory);padding:36px 0 44px;text-align:center}
.badge{display:inline-block;border:1px solid var(--gold);color:var(--gold);border-radius:999px;padding:4px 14px;font-size:13px;letter-spacing:.5px}
.hero h1{font-size:30px;margin:18px 0 12px}
.hero p{opacity:.85;font-size:15px}
.rule{width:44px;height:2px;background:var(--gold);margin:18px auto}

/* sections */
.sec{padding:32px 0}
.sec h2{font-size:22px;margin-bottom:6px}
.sec .lead{color:var(--ink2);font-size:15px;margin-bottom:18px}
.label{font-size:13px;letter-spacing:1px;color:var(--gold-d);font-weight:700;margin-bottom:6px}

.grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.card{background:var(--paper);border:1px solid var(--line);border-radius:var(--r);padding:18px}
a.card{display:block;text-decoration:none;transition:border-color .15s, transform .15s}
a.card:hover{border-color:var(--gold);transform:translateY(-1px)}
.subj .num{font-size:12px;color:var(--gold-d);font-weight:700;letter-spacing:1px}
.subj h3{font-size:22px;margin:4px 0 6px}
.subj p{font-size:13px;color:var(--ink2);line-height:1.5}
.subj .state{display:inline-block;margin-top:10px;font-size:12px;padding:2px 10px;border-radius:999px;background:var(--ivory);color:var(--ink2)}
.subj .state.on{background:var(--navy);color:var(--ivory)}

.kv{display:grid;grid-template-columns:88px 1fr;gap:10px 12px;font-size:15px}
.kv dt{color:var(--ink2)}
.kv dd{margin:0;font-weight:600}

.author{display:flex;gap:16px;align-items:center}
.author img{width:96px;height:120px;object-fit:cover;object-position:50% 18%;border-radius:48px 48px 12px 12px;flex-shrink:0;background:#EDE6DD}
.author h3{font-size:18px}
ul.plain{list-style:none;margin:0;padding:0}
ul.plain li{padding-left:14px;position:relative;margin:4px 0}
ul.plain li::before{content:"";position:absolute;left:0;top:.75em;width:5px;height:5px;border-radius:50%;background:var(--gold)}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;min-height:48px;padding:0 20px;border-radius:12px;
  border:1px solid var(--navy);background:var(--navy);color:var(--ivory);font:inherit;font-weight:700;text-decoration:none;cursor:pointer}
.btn:hover{background:var(--navy2)}
.btn.line{background:transparent;color:var(--navy)}
.btn.line:hover{background:#fff}
.btn.gold{background:var(--gold);border-color:var(--gold);color:var(--navy)}
.btn.block{width:100%}
.btn:disabled{opacity:.4;cursor:default}
.btns{display:flex;gap:10px;flex-wrap:wrap}
.btns .btn{flex:1 1 140px}
.more{display:inline-block;margin-top:12px;font-size:14px;color:var(--gold-d);font-weight:700;text-decoration:none}

/* concept list */
.group{margin-bottom:18px}
.group h3{font-size:16px;font-family:var(--sans);margin-bottom:8px}
.leaf{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:12px 14px;background:var(--paper);border:1px solid var(--line);
  border-radius:12px;margin-bottom:8px;text-decoration:none}
.leaf:hover{border-color:var(--gold)}
.leaf .code{font-size:12px;color:var(--ink2);display:block}
.leaf .cnt{font-size:13px;color:var(--gold-d);font-weight:700;white-space:nowrap}
.leaf.off{opacity:.55;pointer-events:none}

/* ad placeholder */
.ad{border:1px dashed #CFC6B6;border-radius:12px;background:#FBF9F5;color:#A69D8D;font-size:12px;text-align:center;padding:26px 12px;margin:24px 0}

/* quiz */
.qbar{position:sticky;top:0;z-index:5;background:var(--navy);color:var(--ivory)}
.qbar .wrap{display:flex;align-items:center;justify-content:space-between;height:52px;gap:10px}
.qbar .ttl{font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;min-width:0}
.timer{font-variant-numeric:tabular-nums;font-weight:700;color:var(--gold);font-size:17px;white-space:nowrap}
.timer.low{color:#F2A3A3}
.prog{height:4px;background:#ffffff22}
.prog i{display:block;height:100%;background:var(--gold);width:0;transition:width .2s}
.qhead{display:flex;justify-content:space-between;align-items:center;margin:20px 0 10px;font-size:14px;color:var(--ink2)}
.qnum{font-family:var(--serif);font-size:20px;color:var(--navy);font-weight:700}
.qtext{font-size:18px;font-weight:700;line-height:1.6;margin-bottom:16px}
.opts{list-style:none;margin:0;padding:0;display:grid;gap:10px}
.opt{display:flex;gap:12px;align-items:flex-start;width:100%;text-align:left;padding:14px;border:1.5px solid var(--line);border-radius:12px;background:var(--paper);
  font:inherit;color:inherit;cursor:pointer;line-height:1.55}
.opt .n{flex-shrink:0;width:26px;height:26px;border-radius:50%;border:1.5px solid var(--line);display:flex;align-items:center;justify-content:center;font-size:13px;font-weight:700;color:var(--ink2)}
.opt[aria-pressed="true"]{border-color:var(--navy);background:#EEF1F7}
.opt[aria-pressed="true"] .n{background:var(--navy);border-color:var(--navy);color:#fff}
.qnav{display:flex;gap:10px;margin:22px 0 12px}
.qnav .btn{flex:1}
.palette{display:grid;grid-template-columns:repeat(auto-fill,minmax(40px,1fr));gap:6px;margin:8px 0 20px}
.palette button{height:36px;border:1px solid var(--line);border-radius:8px;background:var(--paper);font:inherit;font-size:13px;cursor:pointer;color:var(--ink2)}
.palette button.done{background:var(--navy);border-color:var(--navy);color:#fff}
.palette button.cur{outline:2px solid var(--gold);outline-offset:1px}
details.pal summary{cursor:pointer;font-size:14px;color:var(--ink2);padding:6px 0}

/* modal */
.modal{position:fixed;inset:0;background:#0008;display:none;align-items:center;justify-content:center;padding:var(--gut);z-index:20}
.modal.show{display:flex}
.modal .box{background:var(--paper);border-radius:16px;padding:22px;max-width:420px;width:100%}
.modal h3{font-size:19px;margin-bottom:8px}

/* result */
.score{text-align:center;background:var(--navy);color:var(--ivory);border-radius:18px;padding:28px 16px;margin-top:20px}
.score .big{font-family:var(--serif);font-size:56px;font-weight:700;line-height:1.1}
.score .big small{font-size:20px}
.pass{display:inline-block;margin-top:10px;padding:4px 16px;border-radius:999px;font-weight:700}
.pass.y{background:var(--gold);color:var(--navy)}
.pass.n{background:#ffffff22;color:var(--ivory)}
.stat{display:flex;justify-content:center;gap:18px;margin-top:12px;font-size:14px;opacity:.9;flex-wrap:wrap}
.rev{background:var(--paper);border:1px solid var(--line);border-radius:var(--r);padding:16px;margin-bottom:12px}
.rev .meta{font-size:12px;color:var(--ink2);margin-bottom:6px}
.rev .q{font-weight:700;margin-bottom:10px}
.rev ol{margin:0 0 10px;padding-left:22px}
.rev li{margin:3px 0}
.rev li.ans{color:var(--ok);font-weight:700}
.rev li.mine{color:var(--ng);text-decoration:line-through}
.rev .exp{background:var(--ivory);border-radius:10px;padding:12px;font-size:15px}
.rev .exp b{color:var(--navy)}
.rev .src{font-size:12px;color:var(--ink2);margin-top:8px}
.tag{display:inline-block;font-size:12px;border-radius:6px;padding:1px 8px;margin-right:6px}
.tag.ng{background:var(--ng-bg);color:var(--ng)}
.tag.ok{background:var(--ok-bg);color:var(--ok)}

.notice{background:var(--paper);border-left:3px solid var(--gold);padding:12px 14px;border-radius:0 10px 10px 0;font-size:14px;color:var(--ink2)}


/* ---- 4차: 프리미엄 배지·단원 선택·시험장 화면·공부 화면 ---- */
.pbadge{display:inline-block;vertical-align:middle;margin-left:6px;font-size:11px;font-weight:700;letter-spacing:0;padding:1px 8px;border-radius:999px;background:#F3EAD9;color:var(--gold-d);font-family:var(--sans)}
.pbadge.lock{background:var(--navy);color:var(--gold)}
h3.mini{font-family:var(--sans);font-size:16px;margin-bottom:10px}
.unitform fieldset{border:1px solid var(--line);border-radius:12px;background:var(--paper);margin:0 0 10px;padding:6px 12px 10px;min-width:0}
.unitform fieldset[disabled]{opacity:.55}
.unitform legend{padding:0 4px;max-width:100%}
.chk{display:flex;align-items:center;gap:8px;padding:7px 0;font-size:15px;cursor:pointer;line-height:1.4}
.chk input{width:18px;height:18px;accent-color:var(--navy);flex-shrink:0;margin:0}
.chk.major{font-weight:700;font-size:15px}
.chk .cnt{margin-left:auto;font-size:12px;color:var(--gold-d);font-weight:700;white-space:nowrap;padding-left:8px}
.chk.off{opacity:.5;cursor:default}
.uopts{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin:14px 0 6px}
.chip{display:inline-flex;align-items:center;gap:6px;border:1px solid var(--line);background:var(--paper);border-radius:999px;padding:6px 14px;font-size:14px;cursor:pointer}
.chip input{accent-color:var(--navy);margin:0}
details.scope summary{cursor:pointer;list-style:none;display:flex;align-items:center;gap:8px;padding:12px 14px;background:var(--paper);border:1px solid var(--line);border-radius:12px}
details.scope summary::-webkit-details-marker{display:none}
details.scope summary::after{content:"▾";margin-left:auto;color:var(--ink2)}
details.scope[open] summary::after{content:"▴"}
.chart{width:100%;height:auto;display:block;max-width:420px}
ul.weak{list-style:none;margin:0;padding:0}
ul.weak li{display:flex;justify-content:space-between;gap:10px;padding:8px 0;border-bottom:1px solid var(--line);font-size:15px}
ul.weak li:last-child{border-bottom:none}
ul.weak b{color:var(--ng);white-space:nowrap}

/* 공부 화면 즉시 채점 */
.opt.right{border-color:var(--ok);background:var(--ok-bg)}
.opt.right .n{background:var(--ok);border-color:var(--ok);color:#fff}
.opt.wrongpick{border-color:var(--ng);background:var(--ng-bg)}
.opt.wrongpick .n{background:var(--ng);border-color:var(--ng);color:#fff}
.opt:disabled{cursor:default;color:inherit;opacity:1}
.feedback{margin-top:14px;border-radius:12px;padding:14px;font-size:15px}
.feedback b{display:block;margin-bottom:4px}
.feedback.ok{background:var(--ok-bg);color:#24533D}
.feedback.ng{background:var(--ng-bg);color:#7E2E2E}
.feedback p{color:var(--ink)}

/* 시험장 화면 */
.cbt-tools{background:#F1ECE2;color:var(--ink);border-bottom:1px solid var(--line)}
.cbt-tools .wrap{display:flex;align-items:center;gap:8px;min-height:46px;flex-wrap:nowrap}
.fsz{display:flex;align-items:center;gap:4px}
.fsz .small{margin-right:2px;white-space:nowrap}
@media (max-width:420px){.fsz .small{display:none}}
.fsz button{border:1px solid var(--line);background:var(--paper);border-radius:8px;padding:3px 9px;font:inherit;font-size:13px;cursor:pointer;color:var(--ink2)}
.fsz button[aria-pressed="true"]{background:var(--navy);border-color:var(--navy);color:#fff}
.cbt-tools .left{font-size:14px;margin-left:auto;white-space:nowrap}
.cbt-tools .left b{color:var(--ng)}
.btn.sm{min-height:34px;padding:0 12px;font-size:14px;border-radius:9px}
.cbt-grid{display:block}
.sheet{background:var(--paper);border:1px solid var(--line);border-radius:12px;margin:8px 0 28px}
.sheet-h{font-size:14px;font-weight:700;padding:10px 12px;border-bottom:1px solid var(--line);background:#FBF9F5;border-radius:12px 12px 0 0}
.sheet-b{padding:6px 8px;max-height:280px;overflow:auto}
.srow{display:flex;align-items:center;gap:4px;padding:3px 2px;border-radius:8px}
.srow.cur{background:#F3EAD9}
.sno{width:34px;flex-shrink:0;border:0;background:none;font:inherit;font-size:13px;font-weight:700;color:var(--ink2);cursor:pointer;text-align:right;padding-right:6px}
.bub{width:28px;height:28px;border-radius:50%;border:1.5px solid #C9C1B2;background:#fff;font:inherit;font-size:12px;color:var(--ink2);cursor:pointer;padding:0}
.bub.on{background:var(--navy);border-color:var(--navy);color:#fff}
body.fs0 .qtext{font-size:16px} body.fs0 .opt{font-size:15px}
body.fs2 .qtext{font-size:22px} body.fs2 .opt{font-size:19px}
@media (min-width:900px){
  body.cbt-on .qbar .wrap, body.cbt-on .cbt-tools .wrap, .cbt-main .wrap{max-width:1080px}
  .cbt-grid{display:grid;grid-template-columns:1fr 280px;gap:24px;align-items:start}
  .sheet{position:sticky;top:116px;margin-top:20px}
  .sheet-b{max-height:calc(100vh - 190px)}
  body.fs2 .qtext{font-size:24px} body.fs2 .opt{font-size:20px}
}

/* 안내문 */
.legal h2{font-size:18px;margin:22px 0 6px}
.legal p{color:var(--ink);font-size:15px;line-height:1.75}
.foot .links{margin:4px 0 10px;display:flex;gap:14px;flex-wrap:wrap}

/* footer */
.foot{background:var(--navy);color:#C9CEDA;font-size:13px;padding:28px 0 36px;margin-top:40px}
.foot img{height:18px;width:auto;margin-bottom:14px}
.foot dl{display:grid;grid-template-columns:auto 1fr;gap:2px 10px;margin:0 0 12px}
.foot dd{margin:0}
.foot .dis{opacity:.75;line-height:1.6}
.foot a{color:#C9CEDA}

@media (min-width:720px){
  .hero{padding:56px 0 64px}
  .hero h1{font-size:40px}
  .grid.four{grid-template-columns:repeat(4,1fr)}
  .author img{width:120px;height:150px}
  .qtext{font-size:20px}
}
@media (max-width:360px){
  .top nav{gap:10px;font-size:13px}
  .top .brand span{display:none}
}