/* 深夜自習室ZZZ「共通テストまで〇日」解説ページ（動画の洗練版と同じ色：教科ごとの1色＋白いカード） */
:root{--bg:#141826;--card:#fff;--ink:#141826;--sub:#5b6478;--yel:#FFD54A}
*{box-sizing:border-box}
body{margin:0;background:#eef1f7;color:var(--ink);font-family:'Noto Sans JP',sans-serif;line-height:1.75}
a{color:inherit}
.wrap{max-width:720px;margin:0 auto;padding:0 16px}
header{position:sticky;top:0;z-index:10;background:var(--bg)}
header .wrap{display:flex;align-items:center;justify-content:space-between;height:56px}
header img{height:36px;display:block}
.nagara-mini{background:var(--yel);color:var(--ink);font-weight:900;font-size:13px;text-decoration:none;border-radius:999px;padding:6px 14px}
.top{background:var(--bg);color:#fff;margin:0 -16px;padding:22px 16px 26px;text-align:center}
.top .lb{margin:0;font-weight:900;font-size:22px;letter-spacing:.06em}
.top .big{margin:0;font-weight:900;font-size:28px;line-height:1}
.top .big span{font-family:'Oswald';font-size:110px;margin-right:4px}
.top .sub{margin:8px 0 0;color:#c9d2ea;font-weight:700}
.lead{text-align:center;color:var(--sub);margin:20px 0}
.lead b{color:var(--ink)}
.q{background:var(--card);border-radius:20px;margin:0 0 18px;overflow:hidden;box-shadow:0 6px 18px rgba(20,24,38,.08);border-top:8px solid var(--c)}
.qh{display:flex;align-items:center;gap:10px;padding:14px 18px 0}
.no{font-family:'Oswald';font-size:28px;color:var(--c)}
.tag{background:var(--c);color:#fff;font-weight:900;font-size:14px;border-radius:8px;padding:2px 10px}
.qt{margin:8px 18px 12px;font-weight:900;font-size:19px;line-height:1.6}
.qt u{text-decoration:none;color:var(--c);border-bottom:3px solid var(--c)}
.choices{list-style:none;margin:0 18px 14px;padding:0}
.choices li{display:flex;align-items:center;gap:10px;border:2px solid #e3e7f0;border-radius:12px;padding:8px 12px;margin-bottom:8px;font-weight:700}
.choices b{flex:none;width:28px;height:28px;border-radius:50%;background:var(--c);color:#fff;font-family:'Oswald';display:grid;place-items:center;font-size:16px}
details{border-top:1px solid #e3e7f0}
summary{cursor:pointer;list-style:none;padding:12px 18px;font-weight:900;color:var(--c)}
summary::-webkit-details-marker{display:none}
summary:after{content:' ▼';font-size:12px}
details[open] summary:after{content:' ▲'}
details[open] .choices li.ok{}
details>*:not(summary){margin-left:18px;margin-right:18px}
.ans{font-size:17px}.ans b{color:var(--c)}
h4{margin:14px 18px 2px;font-size:15px;color:var(--c)}
.wrong{list-style:none;padding:0}
.wrong li{display:flex;gap:8px;margin-bottom:6px;color:var(--sub)}
.wrong b{flex:none;color:var(--ink)}
.trend{background:#f4f6fb;border-radius:12px;padding:10px 12px;color:var(--sub);font-size:15px}
.prod{display:block;margin:14px 18px 18px!important;background:var(--yel);border-radius:14px;padding:12px 14px;text-decoration:none;font-size:14px}
.prod b{font-size:15px}
.q details:not([open])+*{}
.q:has(details[open]) .choices li.ok{border-color:var(--c);background:color-mix(in srgb,var(--c) 10%,#fff)}
.pager{display:flex;justify-content:space-between;gap:8px;margin:24px 0;font-weight:700;font-size:14px}
.pager a{text-decoration:none;color:var(--sub)}
.yt{display:block;text-align:center;background:var(--bg);color:#fff;text-decoration:none;border-radius:16px;padding:14px;font-weight:900;margin-bottom:10px}
.yt small{font-weight:500;color:#c9d2ea}
.h1{text-align:center;font-size:26px;margin:24px 0}.h1 small{font-size:16px;color:var(--sub)}
.list{list-style:none;padding:0}
.list a{display:flex;align-items:center;gap:12px;background:#fff;border-radius:14px;padding:12px 14px;margin-bottom:10px;text-decoration:none;box-shadow:0 4px 12px rgba(20,24,38,.06)}
.list .d{font-weight:700}.list .d b{font-family:'Oswald';font-size:28px;margin:0 2px}
.list .m{color:var(--sub);font-size:14px}
.list .s{margin-left:auto;display:flex;gap:4px;flex-wrap:wrap;justify-content:flex-end}
.list i{font-style:normal;color:#fff;font-size:11px;font-weight:900;border-radius:6px;padding:1px 6px}
footer{margin-top:40px;padding:24px 0 40px;background:var(--bg);color:#c9d2ea;font-size:12px;text-align:center}
footer .sns{display:flex;justify-content:center;gap:12px;margin-bottom:10px}
footer .sns a{color:#fff;font-weight:900;text-decoration:none;border:2px solid #ffffff33;border-radius:999px;padding:6px 16px}
footer p{max-width:560px;margin:0 auto 10px}

.blank{display:inline-block;width:3.2em;height:1.05em;border:3px solid var(--c);border-radius:5px;vertical-align:-.18em;margin:0 .1em}