/* DRS Digital School — บทเรียนออนไลน์ (ใช้คู่กับ style.css) */
.ls-sec{padding-top:28px}
.ls-h2{display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:6px 18px;margin:44px 0 18px}
.ls-h2:first-child{margin-top:4px}
.ls-h2 h2{font-size:clamp(22px,2.6vw,30px);font-weight:700}
.ls-h2 h2::before{content:"";display:inline-block;width:26px;height:4px;border-radius:4px;background:var(--yellow);vertical-align:middle;margin-right:12px;transform:translateY(-3px)}
.ls-h2 p{color:var(--muted)}

/* ---------- hero ---------- */
.ls-search{display:flex;align-items:center;gap:8px;max-width:620px;margin-top:22px;background:#fff;border-radius:999px;padding:6px 6px 6px 18px;box-shadow:var(--sh-2)}
.ls-search .ico{color:var(--muted)}
.ls-search input{flex:1;min-width:0;border:0;outline:0;font:inherit;font-size:15.5px;background:none;color:var(--text);padding:8px 2px}
.ls-search .btn{min-height:42px;padding:0 20px}
.ls-search-side{margin:0;box-shadow:none;border:1.5px solid var(--line);padding-left:14px}
.ls-search-side .btn{padding:0 14px}
.ls-stats{display:flex;flex-wrap:wrap;gap:10px;margin-top:22px}
.ls-stats span{display:flex;align-items:baseline;gap:7px;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.22);border-radius:14px;padding:8px 16px;color:#DCEAF9;font-size:14px}
.ls-stats b{font-family:var(--f-display);font-size:22px;color:#fff;font-weight:600}
.ls-pills{display:flex;flex-wrap:wrap;gap:6px;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.2);border-radius:999px;padding:5px}
.ls-pills a{min-width:52px;text-align:center;padding:7px 14px;border-radius:999px;font-family:var(--f-display);font-weight:500;color:#fff;transition:background .2s}
.ls-pills a:hover{background:rgba(255,255,255,.16)}
.ls-pills a.on{background:var(--yellow);color:var(--navy)}
.ls-hero-area{background:linear-gradient(120deg,var(--navy) 0%,var(--blue) 55%,color-mix(in srgb,var(--c) 70%,var(--bright)) 100%)}
.ls-area-head{display:flex;align-items:center;gap:22px}
.ls-area-head .hero-tag{margin-bottom:8px}
.ls-letter{flex:none;display:grid;place-items:center;width:64px;height:64px;border-radius:20px;background:var(--c);color:#fff;font-family:var(--f-display);font-weight:700;font-size:32px;line-height:1;box-shadow:inset 0 -6px 0 rgba(0,0,0,.14)}
.ls-area-head .ls-letter{width:84px;height:84px;font-size:44px;border-radius:26px;border:3px solid rgba(255,255,255,.85)}

/* ---------- ระดับชั้น ---------- */
.ls-band{font-size:15px;font-weight:600;color:var(--blue);letter-spacing:.02em;margin:22px 0 12px}
.ls-grades{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
.ls-grade{position:relative;display:flex;align-items:center;gap:18px;padding:22px 22px 34px;border-radius:var(--r-l);background:#fff;border:1px solid var(--line);overflow:hidden;transition:transform .25s var(--ease),box-shadow .25s,border-color .25s}
.ls-grade:hover{transform:translateY(-4px);box-shadow:var(--sh-2);border-color:#CFE3F8}
.ls-gnum{flex:none;display:flex;align-items:baseline;justify-content:center;width:84px;height:84px;align-items:center;border-radius:24px;background:linear-gradient(140deg,var(--navy),var(--blue));color:#fff;font-family:var(--f-display);font-weight:700;font-size:42px;line-height:1}
.ls-gnum small{font-size:20px;font-weight:600;color:var(--yellow);margin-right:2px}
.ls-gb{display:flex;flex-direction:column;gap:4px;min-width:0;flex:1}
.ls-gb b{font-family:var(--f-display);font-size:19px;font-weight:600;line-height:1.35}
.ls-gb em,.ls-area-b em{font-style:normal;font-size:14px;color:var(--muted)}
.ls-go{flex:none;display:grid;place-items:center;width:38px;height:38px;border-radius:50%;background:var(--soft);color:var(--blue);transition:background .2s,color .2s,transform .25s var(--ease)}
a:hover>.ls-go,a:hover .ls-go{background:var(--yellow);color:var(--navy);transform:translateX(3px)}
.ls-gridge{position:absolute;left:0;right:0;bottom:0;width:100%;height:26px;fill:var(--softblue)}

/* ---------- กลุ่มสาระ ---------- */
.ls-areas{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.ls-area{display:flex;align-items:center;gap:16px;padding:18px;border-radius:var(--r-m);background:#fff;border:1px solid var(--line);border-left:5px solid var(--c);transition:transform .25s var(--ease),box-shadow .25s}
.ls-area:hover{transform:translateY(-3px);box-shadow:var(--sh-2)}
.ls-area-b{display:flex;flex-direction:column;min-width:0;flex:1}
.ls-area-b small{font-size:12.5px;color:var(--muted)}
.ls-area-b b{font-family:var(--f-display);font-size:17px;font-weight:600;line-height:1.35;color:var(--text)}
.ls-area.none{border-left-color:var(--line);background:var(--soft)}
.ls-area.none .ls-letter{background:#C9D3E0;box-shadow:none}
.ls-area.none b{color:#475467}
.ls-tabs{display:flex;gap:8px;overflow-x:auto;padding:2px 2px 12px;margin-bottom:18px;scrollbar-width:thin}
.ls-tabs a{flex:none;display:inline-flex;align-items:center;gap:8px;padding:7px 14px 7px 7px;border-radius:999px;border:1.5px solid var(--line);background:#fff;font-family:var(--f-display);font-size:14px;font-weight:500;white-space:nowrap;transition:border-color .2s}
.ls-tabs a i{display:grid;place-items:center;width:26px;height:26px;border-radius:50%;background:var(--c);color:#fff;font-style:normal;font-size:14px}
.ls-tabs a small{font-size:12px;background:var(--soft);border-radius:99px;padding:0 8px;color:var(--muted)}
.ls-tabs a:hover{border-color:var(--c)}
.ls-tabs a.on{border-color:var(--c);background:color-mix(in srgb,var(--c) 10%,#fff);color:var(--navy)}
.ls-tabs a.none{color:var(--muted)}.ls-tabs a.none i{background:#C9D3E0}
.ls-empty{display:flex;flex-direction:column;gap:6px;align-items:center}.ls-empty b{color:var(--text);font-family:var(--f-display);font-size:18px}

/* ---------- รายวิชา + รายการบทเรียน ---------- */
.ls-subject{margin-top:26px;border:1px solid var(--line);border-radius:var(--r-l);overflow:hidden;background:#fff}
.ls-subj-h{display:flex;align-items:center;gap:16px;padding:18px 22px;background:var(--soft);border-bottom:1px solid var(--line)}
.ls-subj-h h2{font-size:clamp(18px,2vw,22px);font-weight:700}
.ls-subj-h p{display:flex;flex-wrap:wrap;align-items:center;gap:4px;color:var(--muted);font-size:14px;margin-top:2px}
.ls-subj-h p .ico{width:15px;height:15px;margin-left:4px}
.ls-code{flex:none;font-family:var(--f-display);font-weight:600;font-size:15px;color:#fff;background:var(--c);border-radius:12px;padding:8px 12px;letter-spacing:.02em}
.ls-rows{list-style:none;margin:0;padding:8px}
.ls-unit{font-family:var(--f-display);font-weight:600;font-size:14px;color:var(--blue);padding:14px 14px 4px;display:flex;align-items:center;gap:8px}
.ls-unit::before{content:"";width:8px;height:8px;border-radius:2px;background:var(--yellow);transform:rotate(45deg)}
.ls-row{display:flex;align-items:center;gap:16px;padding:12px 14px;border-radius:var(--r-m);transition:background .2s}
.ls-row:hover{background:var(--softblue)}
.ls-no{flex:none;display:grid;place-items:center;width:36px;height:36px;border-radius:50%;border:2px solid var(--line);font-style:normal;font-family:var(--f-display);font-weight:600;color:var(--navy);background:#fff}
.ls-row:hover .ls-no{border-color:var(--bright)}
.ls-rimg{position:relative;flex:none;width:132px;aspect-ratio:16/9;border-radius:12px;background:var(--soft) center/cover no-repeat;display:grid;place-items:center}
.ls-rb{display:flex;flex-direction:column;gap:3px;min-width:0;flex:1}
.ls-rb b{font-family:var(--f-display);font-weight:600;font-size:16.5px;line-height:1.45}
.ls-rb small{color:var(--muted);font-size:14px;line-height:1.55}

/* ---------- การ์ดบทเรียน ---------- */
.lcards{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:20px}
.lcard{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:var(--r-m);overflow:hidden;transition:transform .25s var(--ease),box-shadow .25s}
.lcard:hover{transform:translateY(-4px);box-shadow:var(--sh-2)}
.lc-img{position:relative;display:grid;place-items:center;aspect-ratio:16/9;background:var(--softblue) center/cover no-repeat}
.lc-letter{background:linear-gradient(135deg,var(--c),color-mix(in srgb,var(--c) 55%,#06396D));overflow:hidden}
.lc-letter b{font-family:var(--f-display);font-size:52px;font-weight:700;color:#fff;opacity:.95;line-height:1;position:relative;z-index:1}
.lc-letter svg{position:absolute;left:0;right:0;bottom:6px;width:100%;height:36px;opacity:.8}
.lc-play{display:grid;place-items:center;width:48px;height:48px;border-radius:50%;background:rgba(6,57,109,.82);color:#fff;font-style:normal;box-shadow:0 6px 18px rgba(0,0,0,.25);transition:background .2s,transform .25s var(--ease)}
.lc-play .ico{width:20px;height:20px;fill:currentColor;margin-left:3px}
.lc-play.sm{width:32px;height:32px}.lc-play.sm .ico{width:14px;height:14px;margin-left:2px}
.lcard:hover .lc-play,.ls-row:hover .lc-play{background:var(--yellow);color:var(--navy);transform:scale(1.06)}
.lc-b{display:flex;flex-direction:column;gap:6px;padding:14px 16px 16px;flex:1}
.lc-b>b{font-family:var(--f-display);font-weight:600;font-size:16.5px;line-height:1.45;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
.lc-b>small{color:var(--muted);font-size:13.5px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.lc-tags{display:flex;flex-wrap:wrap;gap:6px}
.lc-g{font-family:var(--f-display);font-size:12.5px;font-weight:600;padding:2px 10px;border-radius:99px;background:var(--navy);color:#fff}
.lc-a{display:inline-flex;align-items:center;gap:6px;font-family:var(--f-display);font-size:12.5px;font-weight:600;padding:2px 10px;border-radius:99px;background:color-mix(in srgb,var(--c) 12%,#fff);color:color-mix(in srgb,var(--c) 80%,#000)}
.lc-a::before{content:"";width:7px;height:7px;border-radius:50%;background:var(--c)}
.chip.lc-a{font-size:13px;padding:3px 10px}
.lc-meta{display:flex;flex-wrap:wrap;gap:4px 12px;margin-top:auto;padding-top:4px;font-size:13px;color:var(--muted)}
.lc-meta span{display:inline-flex;align-items:center;gap:4px}.lc-meta .ico{width:14px;height:14px}
.ls-teach{display:flex;align-items:center;justify-content:center;gap:8px;margin-top:40px;color:var(--muted);font-size:14.5px;text-align:center}
.ls-teach .ico{color:var(--blue)}

/* ---------- หน้าบทเรียน ---------- */
.ls-ownerbar{background:#FFF8DB;border-bottom:1px solid #F5E3A3;font-size:14.5px;color:#7A5A00}
.ls-ownerbar .wrap{display:flex;flex-wrap:wrap;align-items:center;gap:8px 12px;padding-block:10px}
.ls-ownerbar .btn{margin-left:auto;min-height:38px;padding:0 16px;font-size:14px}
.ls-draft,.ls-live{font-family:var(--f-display);font-weight:600;font-size:12.5px;padding:2px 10px;border-radius:99px;background:#7A5A00;color:#fff}
.ls-live{background:var(--ok)}
.ls-grid{padding-top:30px}
.ls-subj{font-family:var(--f-display);font-weight:500;color:var(--blue);margin-bottom:6px}
.ls-art .art-head h1{max-width:none}
.ls-by{display:flex;align-items:center;gap:10px;margin-top:16px}
.ls-by>span:last-child{display:flex;flex-direction:column;line-height:1.35;font-family:var(--f-display);font-weight:500}
.ls-by small{font-family:var(--f-body);font-weight:400;font-size:12.5px;color:var(--muted)}
.ls-av{display:grid;place-items:center;width:40px;height:40px;border-radius:50%;background:var(--navy);color:var(--yellow);font-family:var(--f-display);font-weight:600}
.ls-lead{margin-top:16px;font-size:17.5px;line-height:1.8;color:#344054;max-width:72ch}
.ls-obj{margin-top:24px;padding:18px 22px;border-radius:var(--r-m);background:var(--softblue);border:1px solid #CFE3F8}
.ls-obj h2{display:flex;align-items:center;gap:8px;font-size:17px;color:var(--navy);margin-bottom:8px}
.ls-obj h2 .ico{color:var(--blue)}
.ls-obj ol{margin:0;padding-left:1.4em;display:flex;flex-direction:column;gap:4px}
.ls-content{margin-top:28px;display:flex;flex-direction:column;gap:22px}
.ls-text{font-size:17px;line-height:1.85;max-width:74ch;overflow-wrap:anywhere}
.ls-text>*+*{margin-top:.85em}
.ls-text h3{font-size:21px;color:var(--navy);margin-top:1.3em}.ls-text h3:first-child,.ls-text h4:first-child{margin-top:0}
.ls-text h4{font-size:18px;color:var(--navy);margin-top:1.1em}
.ls-text ul,.ls-text ol{padding-left:1.4em;margin-bottom:0}
.ls-text li+li{margin-top:.25em}
.ls-text a{color:var(--blue);text-decoration:underline;text-underline-offset:3px;overflow-wrap:anywhere}
.ls-text blockquote{margin:0;padding:14px 20px;border-left:4px solid var(--yellow);background:#FFFBEA;border-radius:0 12px 12px 0}
.ls-media,.ls-img{margin:0}
.ls-frame{position:relative;width:100%;border-radius:var(--r-m);overflow:hidden;background:#0B1B33;box-shadow:var(--sh-1)}
.ls-frame iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.ls-media.ls-youtube .ls-frame[style*="9/16"]{max-width:380px;margin-inline:auto}
.ls-media.ls-form .ls-frame,.ls-media.ls-doc .ls-frame{max-height:80vh;aspect-ratio:auto!important;height:80vh;background:#fff;border:1px solid var(--line)}
.ls-media figcaption,.ls-img figcaption{display:flex;flex-wrap:wrap;justify-content:space-between;gap:4px 16px;margin-top:8px;font-size:14px;color:var(--muted)}
.ls-media figcaption a{color:var(--blue);font-family:var(--f-display);font-weight:500}
.ls-img img{display:block;max-width:100%;height:auto;margin-inline:auto;border-radius:var(--r-m)}
.ls-img figcaption{justify-content:center}
.ls-file,.ls-link{display:flex;align-items:center;gap:14px;padding:14px 16px;border:1px solid var(--line);border-radius:var(--r-m);background:#fff;transition:border-color .2s,box-shadow .2s}
.ls-file:hover,.ls-link:hover{border-color:#9CC8F2;box-shadow:var(--sh-1)}
.ls-fbadge{flex:none;display:grid;place-items:center;width:48px;height:56px;border-radius:10px;color:#fff;font-family:var(--f-display);font-weight:700;font-size:13px;letter-spacing:.04em;position:relative}
.ls-fbadge::after{content:"";position:absolute;top:0;right:0;border-style:solid;border-width:0 12px 12px 0;border-color:transparent #fff transparent transparent;opacity:.85}
.ls-fmeta{display:flex;flex-direction:column;min-width:0;flex:1}
.ls-fmeta b{font-family:var(--f-display);font-weight:600;line-height:1.45;overflow-wrap:anywhere}
.ls-fmeta small{color:var(--muted);font-size:13px;overflow-wrap:anywhere}
.ls-fact{display:flex;flex-wrap:wrap;gap:8px;justify-content:flex-end}
.ls-fbtn{display:inline-flex;align-items:center;min-height:40px;padding:0 16px;border-radius:999px;border:1.5px solid var(--line);font-family:var(--f-display);font-weight:500;font-size:14px;color:var(--blue);background:#fff;transition:background .2s,border-color .2s}
.ls-fbtn:hover{border-color:var(--bright)}
.ls-fbtn.ls-fdl{background:var(--blue);border-color:var(--blue);color:#fff}.ls-fbtn.ls-fdl:hover{background:var(--navy)}
.ls-lic{flex:none;display:grid;place-items:center;width:48px;height:48px;border-radius:14px;background:var(--yellow);color:var(--navy);font-size:22px;font-weight:700}
.ls-link .ls-fmeta b{color:var(--navy)}
.ls-nav{margin-top:36px}
.ls-side{gap:18px}
.ls-toc h2,.ls-side .side-box h2{display:flex;align-items:center;gap:8px}
.ls-toc h2 .ico{color:var(--blue)}
.ls-toc>p{font-size:13.5px;color:var(--muted);margin:-6px 0 10px}
.ls-toc ol{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;max-height:520px;overflow:auto}
.ls-toc li a{display:flex;gap:10px;align-items:flex-start;padding:9px 6px;border-top:1px solid var(--line);font-size:14.5px;line-height:1.5;border-radius:10px}
.ls-toc li:first-child a{border-top:0}
.ls-toc li a:hover{color:var(--blue)}
.ls-toc li a i{flex:none;display:grid;place-items:center;width:24px;height:24px;border-radius:50%;background:#fff;border:1.5px solid var(--line);font-style:normal;font-size:12px;font-weight:600;font-family:var(--f-display);margin-top:1px}
.ls-toc li a small{display:block;color:var(--muted);font-size:12.5px}
.ls-toc li.on a{background:#fff;color:var(--navy);font-weight:600;border-top-color:transparent}
.ls-toc li.on a i{background:var(--yellow);border-color:var(--gold);color:var(--navy)}
.ls-toc li.on+li a{border-top-color:transparent}

@media (max-width:1199px){
  .lcards{grid-template-columns:repeat(3,minmax(0,1fr))}
  .ls-areas{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:900px){
  .ls-grades{grid-template-columns:1fr 1fr}
  .lcards{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (max-width:767px){
  .ls-search{margin-top:16px;padding-left:14px}
  .ls-search .btn{padding:0 14px}
  .ls-stats{gap:8px}.ls-stats span{padding:6px 12px}.ls-stats b{font-size:19px}
  .ls-grades{grid-template-columns:1fr;gap:12px}
  .ls-grade{padding:16px 16px 28px;gap:14px}
  .ls-gnum{width:64px;height:64px;font-size:32px;border-radius:18px}.ls-gnum small{font-size:16px}
  .ls-areas{grid-template-columns:1fr;gap:10px}
  .ls-area{padding:14px;gap:12px}
  .ls-letter{width:52px;height:52px;font-size:26px;border-radius:16px}
  .ls-area-head{gap:14px}.ls-area-head .ls-letter{width:60px;height:60px;font-size:30px;border-radius:18px}
  .ls-pills{border-radius:18px}.ls-pills a{min-width:0;flex:1 1 calc(33% - 6px);padding:6px 8px}
  .lcards{grid-template-columns:1fr;gap:14px}
  .lcard{flex-direction:row}
  .lcard .lc-img{flex:none;width:38%;aspect-ratio:auto;min-height:100%}
  .lc-letter b{font-size:34px}.lc-letter svg{height:24px}
  .lc-b{padding:10px 12px;gap:4px}.lc-b>b{font-size:15px}
  .lcard .lc-meta span:first-child:not(:only-child){display:none}
  .lc-play{width:38px;height:38px}
  .ls-subj-h{padding:14px 16px;gap:12px}
  .ls-rows{padding:4px}
  .ls-row{gap:10px;padding:10px 8px;align-items:flex-start}
  .ls-no{width:30px;height:30px;font-size:14px}
  .ls-rimg{width:96px}
  .ls-row .ls-go{display:none}
  .ls-rb b{font-size:15.5px}.ls-rb small{display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}
  .ls-lead{font-size:16px}
  .ls-text{font-size:16px}
  .ls-file{flex-wrap:wrap;padding:12px}.ls-fact{width:100%;justify-content:stretch}.ls-fbtn{flex:1;justify-content:center}
  .ls-fbadge{width:40px;height:48px;font-size:12px}
  .ls-ownerbar .btn{margin-left:0}
  .art-nav.ls-nav{grid-template-columns:1fr}.art-nav.ls-nav a.r{grid-column:auto}
}
.ls-area-head .hero-tag{letter-spacing:.03em;text-transform:none}
.ls-teach{flex-wrap:wrap}
@media (max-width:767px){.ls-page .pg-hero-sm .wrap{padding-block:16px 14px}.ls-teach{font-size:14px}}

/* รายวิชาแบบพับเก็บ (ดรอปลิสต์) */
.ls-subj-pick{display:flex;flex-wrap:wrap;align-items:center;gap:10px 12px;margin-top:22px;padding:14px 16px;background:#fff;border:1px solid var(--line);border-radius:var(--r-l)}
.ls-subj-pick label{display:inline-flex;align-items:center;gap:8px;font-family:var(--f-display);font-weight:600}
.ls-subj-pick label .ico{width:18px;height:18px}
.ls-subj-pick select{flex:1;min-width:220px;font:inherit;font-size:15px;padding:10px 38px 10px 14px;border:1px solid var(--line);border-radius:12px;background:#fff}
.ls-all{font:inherit;font-size:14px;font-weight:600;border:1px solid var(--line);background:var(--soft);border-radius:12px;padding:9px 14px;cursor:pointer}
details.ls-subject{margin-top:14px}
details.ls-subject>summary{list-style:none;cursor:pointer;user-select:none}
details.ls-subject>summary::-webkit-details-marker{display:none}
details.ls-subject:not([open])>summary{border-bottom:0}
details.ls-subject>summary>div{flex:1;min-width:0}
details.ls-subject>summary:hover{background:color-mix(in srgb,var(--soft) 80%,#000 4%)}
details.ls-subject>summary:focus-visible{outline:3px solid var(--c,#1689E8);outline-offset:-3px}
.ls-tog{flex:none;display:inline-flex;align-items:center;gap:6px;font-size:14px;font-weight:600;color:var(--muted)}
.ls-tog em{font-style:normal}.ls-tog .ico{width:20px;height:20px;transition:transform .2s}
details.ls-subject[open] .ls-tog .ico{transform:rotate(180deg)}
details.ls-subject[open] .ls-tog-o,details.ls-subject:not([open]) .ls-tog-c{display:none}
@media (max-width:640px){.ls-tog em{display:none}.ls-subj-pick label{flex:1}.ls-subj-pick select{order:3;flex:1 1 100%;min-width:0;width:100%}}