:root{color-scheme:light;--teal:#2b7a73;--teal-d:#205f59;--mint:#eef5f3;--line:#d2e2de;--ink:#163436;--muted:#6d807c;--coral:#e8553f;--coral-d:#c4412d;--coral-soft:#fff2ee;--shadow:0 18px 50px rgba(29,72,67,.13);font-family:"NanumSquareRound",Pretendard,"Apple SD Gothic Neo","Malgun Gothic",system-ui,sans-serif;color:var(--ink);background:#eef5f3}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:70px}
body{margin:0;min-height:100vh;background:radial-gradient(circle at 8% 0,rgba(64,153,142,.16),transparent 30rem),radial-gradient(circle at 96% 6%,rgba(232,85,63,.08),transparent 24rem),linear-gradient(180deg,#f6faf9,#eef5f3);color:var(--ink);-webkit-font-smoothing:antialiased;word-break:keep-all;overflow-wrap:anywhere}
img{max-width:100%;height:auto;display:block}
a{color:inherit}
.wrap{max-width:1120px;margin:0 auto;padding:18px 16px 64px}

/* 브랜드 바 */
.brandbar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:8px 14px 8px 8px;background:#fff;border:1px solid var(--line);border-radius:22px;box-shadow:0 8px 24px rgba(29,72,67,.08)}
.brand{display:block;min-width:0}
.brand img{height:68px;width:auto}
.class-badge{flex:0 0 auto;padding:9px 14px;border-radius:999px;background:var(--coral);color:#fff;font-weight:900;font-size:14px;box-shadow:0 6px 16px rgba(232,85,63,.26)}

/* 히어로 */
.hero{position:relative;overflow:hidden;margin-top:14px;padding:28px 26px 26px;border-radius:28px;color:#fff;background:linear-gradient(135deg,var(--teal-d),var(--teal));box-shadow:var(--shadow)}
.hero::after{content:"";position:absolute;right:-70px;top:-70px;width:280px;height:280px;border-radius:50%;background:rgba(255,255,255,.07);pointer-events:none}
.hero.compact{padding:24px 24px 22px}
.eyebrow{margin:0;font-size:13px;font-weight:800;opacity:.86}
.eyebrow.dark{color:var(--coral);opacity:1}
.hero h1{margin:8px 0 6px;font-size:clamp(28px,5.4vw,44px);line-height:1.18;font-weight:900;letter-spacing:-.8px}
.hero .sub{margin:0;font-size:15px;opacity:.9}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:18px}
.chips a{display:inline-flex;align-items:center;gap:7px;padding:8px 12px;border-radius:999px;background:rgba(255,255,255,.14);border:1px solid rgba(255,255,255,.3);color:#fff;text-decoration:none;font-size:13px;font-weight:800}
.chips a b{display:inline-grid;place-items:center;min-width:22px;height:22px;padding:0 6px;border-radius:999px;background:#fff;color:var(--teal-d);font-size:12px}
.how{margin:16px 0 0;max-width:660px;font-size:14.5px;line-height:1.7;color:rgba(255,255,255,.93)}
.actions{position:relative;z-index:1;display:flex;flex-wrap:wrap;gap:10px;margin-top:18px}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:46px;padding:0 18px;border-radius:14px;font-weight:900;font-size:15px;text-decoration:none}
.btn.primary{background:#fff;color:var(--teal-d);box-shadow:0 8px 20px rgba(10,40,36,.18)}
.btn.ghost{border:1px solid rgba(255,255,255,.55);color:#fff}
.btn.disabled{opacity:.72}

/* 구역 탭 */
.tabs{position:sticky;top:0;z-index:20;display:flex;gap:6px;margin:14px -16px 0;padding:10px 16px;background:rgba(238,245,243,.88);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);overflow-x:auto;scrollbar-width:none}
.tabs::-webkit-scrollbar{display:none}
.tabs a{flex:0 0 auto;padding:10px 14px;border-radius:12px;background:#fff;border:1px solid var(--line);text-decoration:none;font-weight:900;font-size:14px;color:var(--teal-d)}

/* 출제 포인트 */
.point-card{display:grid;gap:18px;margin-top:14px;padding:22px;border-radius:24px;background:#fff;border:1px solid var(--line);box-shadow:0 10px 30px rgba(29,72,67,.08)}
.point-card h2{margin:6px 0 4px;font-size:22px;letter-spacing:-.4px}
@media(min-width:760px){.point-card{grid-template-columns:1.1fr 1fr;align-items:center}}

/* 섹션 */
.section{margin-top:34px}
.section-head{display:flex;flex-wrap:wrap;align-items:baseline;gap:6px 12px;margin:0 2px 14px}
.section-head h2{margin:0;padding-left:12px;border-left:6px solid var(--coral);font-size:24px;line-height:1.1;letter-spacing:-.5px}
.section-head p{margin:0;color:var(--muted);font-size:13.5px;font-weight:700}
.problems{display:grid;grid-template-columns:1fr;gap:16px;align-items:start}
@media(min-width:900px){.problems{grid-template-columns:1fr 1fr}}

/* 문항 카드 */
.problem{padding:16px;border:1px solid var(--line);border-radius:22px;background:#fff;box-shadow:0 10px 26px rgba(29,72,67,.07);scroll-margin-top:70px;transition:box-shadow .3s,border-color .3s}
.problem.flash{border-color:var(--coral);box-shadow:0 0 0 4px rgba(232,85,63,.2),0 10px 26px rgba(29,72,67,.07)}
.problem-head{display:flex;align-items:center;gap:12px;margin-bottom:12px}
.problem-head .no{flex:0 0 auto;display:grid;place-items:center;width:40px;height:40px;border-radius:13px;background:var(--teal);color:#fff;font-weight:900;font-size:18px}
.problem-head strong{display:block;font-size:17px;letter-spacing:-.3px}
.problem-head small{display:block;margin-top:3px;color:var(--muted);font-size:12.5px;font-weight:700}
.problem-img{margin:0;padding:10px;border:1px solid #e5eeeb;border-radius:14px;background:#fff}
.problem-img img{width:100%}

/* 해설 클립 */
.clips{display:grid;gap:10px;margin-top:12px}
.clips:has(> :nth-child(2)){grid-template-columns:1fr 1fr}
.clip{appearance:none;display:block;width:100%;padding:0;border:1px solid var(--line);border-radius:16px;background:var(--mint);color:inherit;font:inherit;text-align:left;cursor:pointer;overflow:hidden}
.clip:focus-visible{outline:3px solid var(--coral);outline-offset:2px}
.clip-thumb{position:relative;display:block;aspect-ratio:16/9;background:#fff}
.clip-thumb img{width:100%;height:100%;object-fit:cover}
.play{position:absolute;left:50%;top:50%;width:60px;height:60px;border-radius:50%;background:rgba(232,85,63,.95);box-shadow:0 8px 22px rgba(0,0,0,.25);transform:translate(-50%,-50%);transition:transform .15s}
.play::after{content:"";position:absolute;left:24px;top:18px;border-style:solid;border-width:12px 0 12px 19px;border-color:transparent transparent transparent #fff}
.clip:hover .play,.clip:focus-visible .play{transform:translate(-50%,-50%) scale(1.08)}
.len{position:absolute;right:8px;bottom:8px;padding:3px 7px;border-radius:7px;background:rgba(22,52,54,.88);color:#fff;font-size:12px;font-weight:800}
.clip-meta{display:grid;gap:2px;padding:10px 12px 12px}
.clip-meta b{color:var(--coral);font-size:12px;font-weight:900}
.clip-meta span{font-size:14px;font-weight:800;line-height:1.4}
.clip-meta em{color:var(--muted);font-size:12px;font-style:normal}
.clip.pending{cursor:default;opacity:.78}
.clip.pending img{aspect-ratio:16/9;object-fit:cover}
.player{overflow:hidden;border:1px solid var(--line);border-radius:16px;background:#000}
.player iframe{display:block;width:100%;aspect-ratio:16/9;border:0}
.player-link{display:block;padding:9px 12px;background:#fff;color:var(--teal-d);font-size:12.5px;font-weight:800;text-decoration:none}

/* 요점 · 정답 */
.points{display:grid;gap:7px;margin:12px 0 0;padding:0;list-style:none}
.points li{position:relative;padding:9px 12px 9px 31px;border-radius:12px;background:var(--mint);font-size:14px;line-height:1.55}
.points li::before{content:"";position:absolute;left:13px;top:16px;width:8px;height:8px;border-radius:50%;background:var(--teal)}
.self-note{display:grid;gap:4px;margin-top:12px;padding:12px 14px;border:1px dashed #efb4a7;border-radius:14px;background:var(--coral-soft);font-size:14px;line-height:1.6}
.self-note b{color:var(--coral-d)}
.self-note a{color:var(--teal-d);font-weight:900}
.answer{margin-top:10px;border:1px solid var(--line);border-radius:14px;background:#fbfdfc}
.answer summary{padding:12px 14px;cursor:pointer;list-style:none;color:var(--teal-d);font-size:14px;font-weight:900}
.answer summary::-webkit-details-marker{display:none}
.answer summary::after{content:"＋";float:right}
.answer[open] summary::after{content:"－"}
.answer p{margin:0;padding:0 14px 14px;font-size:18px;font-weight:900}

/* 목록 · 푸터 */
.set-card{display:grid;max-width:560px;overflow:hidden;border:1px solid var(--line);border-radius:22px;background:#fff;text-decoration:none;box-shadow:0 10px 26px rgba(29,72,67,.08)}
.set-card span{display:grid;gap:4px;padding:14px 16px 16px}
.set-card b{font-size:17px}
.set-card small{color:var(--muted);font-weight:700}
.foot{display:flex;align-items:center;gap:16px;margin-top:44px;padding:18px;border:1px solid var(--line);border-radius:22px;background:#fff}
.foot img{flex:0 0 auto;width:84px;height:84px;border-radius:18px}
.foot strong{font-size:15px}
.foot p{margin:6px 0 0;color:var(--muted);font-size:13px;line-height:1.6}
.foot .src a{color:var(--teal-d);font-weight:800}

@media(max-width:560px){
  .brand img{height:48px}
  .class-badge{padding:8px 10px;font-size:12px}
  .hero{padding:22px 18px;border-radius:24px}
  .problem{padding:12px;border-radius:18px}
  .clips:has(> :nth-child(2)){grid-template-columns:1fr}
  .foot{align-items:flex-start}
  .foot img{width:64px;height:64px}
}

/* 격자 칸이 문항 이미지의 원본 폭만큼 늘어나 모바일에서 넘치지 않도록 */
.problems,.clips{grid-template-columns:minmax(0,1fr)}
@media(min-width:900px){.problems{grid-template-columns:repeat(2,minmax(0,1fr))}}
.clips:has(> :nth-child(2)){grid-template-columns:repeat(2,minmax(0,1fr))}
@media(max-width:560px){.clips:has(> :nth-child(2)){grid-template-columns:minmax(0,1fr)}}
@media(min-width:760px){.point-card{grid-template-columns:minmax(0,1.1fr) minmax(0,1fr)}}
.problem,.point-card>*,.clip,.player{min-width:0}