/* Help Center — layout bài, tab hệ điều hành, FAQ, ảnh. Dùng token của site.css. */
.help-main { max-width: 1080px; margin: 0 auto; padding: 100px 16px 64px; }
.crumbs { font-size: 13px; color: var(--muted); margin-bottom: 14px; }
.crumbs a { color: var(--muted); text-decoration: none; } .crumbs a:hover { color: var(--c1); }
.help-main h1 { font-size: clamp(28px, 4.4vw, 42px); letter-spacing: -1px; line-height: 1.15; margin-bottom: 10px; }
.help-main h2 { font-size: 22px; letter-spacing: -.4px; margin: 34px 0 12px; }
.lead { color: var(--muted); font-size: 17px; max-width: 720px; }
.applies { display: inline-flex; gap: 8px; align-items: center; margin: 14px 0 6px; padding: 6px 12px; border-radius: 999px;
  background: var(--card); border: 1px solid var(--border); font-size: 13px; color: var(--muted); }
.applies b { color: var(--text); }

/* Tab hệ điều hành */
.os-tabs { display: flex; gap: 6px; flex-wrap: wrap; margin: 22px 0 8px; padding: 5px; border-radius: 14px;
  background: var(--card); border: 1px solid var(--border); width: fit-content; max-width: 100%; }
.os-tabs a { padding: 8px 14px; border-radius: 10px; font-size: 14px; font-weight: 600; text-decoration: none; color: var(--muted); white-space: nowrap; }
.os-tabs a:hover { color: var(--text); }
.os-tabs a.on { background: var(--grad); color: #fff; }
.os-tabs a.soon { opacity: .55; }
.os-tabs a .tag { font-size: 10.5px; font-weight: 700; margin-left: 5px; text-transform: uppercase; letter-spacing: .5px; }

/* Các bước */
ol.steps-list { list-style: none; counter-reset: s; margin: 18px 0; display: grid; gap: 18px; }
ol.steps-list > li { counter-increment: s; position: relative; padding: 18px 18px 18px 64px; border-radius: 16px;
  background: var(--card); border: 1px solid var(--border); }
ol.steps-list > li::before { content: counter(s); position: absolute; left: 18px; top: 16px; width: 30px; height: 30px;
  border-radius: 50%; background: var(--grad); color: #fff; font-weight: 800; display: grid; place-items: center; font-size: 14px; }
.help-main p, .help-main li { line-height: 1.65; }
.help-main ul:not(.links) { margin: 10px 0 10px 22px; }
.help-main code { font-size: .9em; padding: 1px 6px; border-radius: 6px; background: var(--bg3); }
.ui { font-weight: 700; color: var(--text); padding: 1px 7px; border-radius: 7px; background: var(--bg3); border: 1px solid var(--border); white-space: nowrap; }

/* Ảnh */
figure.shot { margin: 14px 0 4px; }
figure.shot .frame { position: relative; display: inline-block; max-width: min(100%, 340px); border-radius: 22px; overflow: hidden;
  border: 6px solid var(--card-solid); box-shadow: var(--shadow); background: var(--bg3); cursor: zoom-in; }
figure.shot img { display: block; width: 100%; height: auto; }
figure.shot figcaption { font-size: 13px; color: var(--muted); margin-top: 8px; }
figure.shot.pending .frame { width: 260px; aspect-ratio: 9/19; display: grid; place-items: center; text-align: center;
  padding: 18px; font-size: 13px; color: var(--muted); border-style: dashed; border-color: var(--border-strong); cursor: default; }
.callout { position: absolute; width: 28px; height: 28px; margin: -14px 0 0 -14px; border-radius: 50%; background: var(--c1); color: #fff;
  font-weight: 800; font-size: 13px; display: grid; place-items: center; box-shadow: 0 0 0 4px rgba(239,83,80,.3); }
.callout-box { position: absolute; border: 3px solid var(--c1); border-radius: 10px; box-shadow: 0 0 0 4px rgba(239,83,80,.2); }
.lightbox { position: fixed; inset: 0; z-index: 300; background: rgba(0,0,0,.82); display: none; place-items: center; padding: 16px; cursor: zoom-out; }
.lightbox.open { display: grid; } .lightbox img { max-height: 92vh; max-width: 100%; border-radius: 18px; }

/* Ghi chú */
.note { margin: 16px 0; padding: 14px 16px; border-radius: 14px; border: 1px solid var(--border); background: var(--grad-soft); }
.note::before { content: 'ⓘ  Note'; display: block; font-weight: 700; font-size: 13px; margin-bottom: 4px; color: var(--c1); }
.note.tip::before { content: '💡  Tip'; }

/* Trang chủ trợ giúp */
.search-box { width: 100%; max-width: 560px; margin: 22px 0; padding: 14px 18px; border-radius: 14px; font-size: 16px;
  border: 1px solid var(--border-strong); background: var(--card-solid); color: var(--text); }
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px; margin: 16px 0; }
.card { display: block; padding: 18px; border-radius: 16px; background: var(--card); border: 1px solid var(--border); text-decoration: none; transition: border-color .2s, transform .2s; }
.card:hover { border-color: var(--c1); transform: translateY(-2px); }
.card h3 { font-size: 16px; margin-bottom: 4px; } .card p { font-size: 13.5px; color: var(--muted); }
.card .ico { font-size: 22px; margin-bottom: 8px; }
.results { margin-top: 6px; } .results a { display: block; padding: 10px 2px; border-bottom: 1px solid var(--border); text-decoration: none; }
.results a small { color: var(--muted); display: block; }

/* FAQ */
.faq-filter { display: flex; gap: 6px; flex-wrap: wrap; margin: 18px 0; }
.faq-filter button { padding: 7px 13px; border-radius: 999px; border: 1px solid var(--border); background: var(--card); color: var(--muted); font: inherit; font-size: 13.5px; cursor: pointer; }
.faq-filter button.on { background: var(--grad); color: #fff; border-color: transparent; }
details.faq { border: 1px solid var(--border); border-radius: 14px; background: var(--card); margin: 10px 0; }
details.faq summary { cursor: pointer; padding: 16px 18px; font-weight: 650; list-style: none; display: flex; justify-content: space-between; gap: 12px; }
details.faq summary::-webkit-details-marker { display: none; }
details.faq summary::after { content: '+'; color: var(--c1); font-size: 20px; line-height: 1; }
details.faq[open] summary::after { content: '−'; }
details.faq .ans { padding: 0 18px 16px; color: var(--muted); }
details.faq .ans a { color: var(--c1); }
.faq-cat { margin-top: 30px; font-size: 13px; text-transform: uppercase; letter-spacing: 1px; color: var(--muted); }
.os-badges { display: inline-flex; gap: 4px; margin-left: 6px; } .os-badges span { font-size: 11px; padding: 1px 7px; border-radius: 999px; border: 1px solid var(--border); color: var(--muted); font-weight: 600; }
.soon-box { padding: 28px; border-radius: 18px; border: 1px dashed var(--border-strong); background: var(--card); margin: 20px 0; }