:root {
  --bg: #0f1115;
  --panel: #171a21;
  --panel-2: #1e222b;
  --line: #2a2f3a;
  --ink: #e9eaee;
  --ink-soft: #b3b7c2;
  --muted: #838895;
  --brand: #e50914;
  --accent: #4f8ef7;
  --good: #37b26b;
  --warn: #e0a13c;
  --bad: #e5484d;
  --radius: 14px;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f6f8; --panel: #ffffff; --panel-2: #f0f2f5; --line: #e2e5ea;
    --ink: #1a1c22; --ink-soft: #45495a; --muted: #767b88;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body { background: var(--bg); color: var(--ink); font-family: var(--sans); line-height: 1.55; font-size: 15px; }
[hidden] { display: none !important; }
img, video { max-width: 100%; }

.page { max-width: 860px; margin: 0 auto; padding: 32px 18px 90px; }
.masthead { margin-bottom: 22px; }
.kicker { font: 600 11px/1 var(--mono); letter-spacing: .16em; text-transform: uppercase; color: var(--muted); margin: 0 0 8px; }
.masthead h1 { font-size: 27px; margin: 0 0 8px; letter-spacing: -.01em; }
.lede { color: var(--ink-soft); margin: 0; font-size: 14px; }

.card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 20px 22px; margin-bottom: 16px; }
.card h2 { font-size: 16px; margin: 0 0 14px; display: flex; align-items: center; gap: 10px; }
.card h2 .n { width: 22px; height: 22px; border-radius: 7px; background: var(--brand); color: #fff; font: 700 12px/22px var(--mono); text-align: center; flex: none; }
.hint { font-size: 12.5px; color: var(--muted); margin: -6px 0 14px; }

label { display: block; font-size: 12.5px; font-weight: 600; color: var(--ink-soft); }
label.block { margin-bottom: 14px; }
.req { color: var(--brand); }
input[type=text], input[type=email], input[type=date], select, textarea {
  width: 100%; margin-top: 6px; font: inherit; font-size: 14px;
  background: var(--panel-2); color: var(--ink); border: 1px solid var(--line);
  border-radius: 10px; padding: 9px 11px; outline: none;
}
textarea { resize: vertical; }
input:focus, select:focus, textarea:focus { border-color: var(--accent); }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px 16px; }
@media (max-width: 620px) { .grid2 { grid-template-columns: 1fr; } }

/* Hạng mục */
.cat { border: 1px solid var(--line); border-radius: 12px; margin-bottom: 12px; overflow: hidden; background: var(--panel-2); }
.cat > summary { list-style: none; cursor: pointer; padding: 13px 15px; display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 14px; }
.cat > summary::-webkit-details-marker { display: none; }
.cat > summary .chev { margin-left: auto; color: var(--muted); transition: transform .15s; }
.cat[open] > summary .chev { transform: rotate(90deg); }
.cat > summary .catprog { font: 600 11px/1 var(--mono); color: var(--muted); }
.cat-body { padding: 4px 15px 14px; }

.feat { border-top: 1px solid var(--line); padding: 14px 0; }
.feat:first-child { border-top: none; }
.feat h4 { margin: 0 0 4px; font-size: 13.5px; }
.expect { font-size: 12.5px; color: var(--ink-soft); background: color-mix(in srgb, var(--accent) 10%, transparent); border-left: 2px solid var(--accent); border-radius: 6px; padding: 7px 10px; margin: 4px 0 10px; }
.expect b.lbl { font: 700 9.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--accent); display: inline-block; margin-right: 6px; }

.rateline { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.stars { display: inline-flex; gap: 3px; }
.stars button { font: inherit; background: none; border: none; cursor: pointer; font-size: 22px; line-height: 1; color: var(--line); padding: 0 1px; }
.stars button.on { color: var(--warn); }
.stars button:hover, .stars button:hover ~ button { }
.na { display: inline-flex; align-items: center; gap: 5px; font-size: 12px; color: var(--muted); font-weight: 600; cursor: pointer; }
.na input { width: auto; margin: 0; }
.feat textarea { margin-top: 8px; min-height: 34px; }
.feat.rated { }
.feat.rated h4::after { content: " ✓"; color: var(--good); font-size: 12px; }
.feat.skipped { opacity: .6; }

.dropzone { display: flex; align-items: center; justify-content: center; text-align: center; border: 1.5px dashed var(--line); border-radius: 12px; padding: 22px; color: var(--muted); font-weight: 600; font-size: 13px; cursor: pointer; position: relative; }
.dropzone.drag { border-color: var(--accent); color: var(--accent); }
.dropzone input { position: absolute; inset: 0; opacity: 0; cursor: pointer; }
.previews { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
.previews .pv { width: 92px; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; background: var(--panel-2); position: relative; }
.previews .pv img, .previews .pv video { width: 100%; height: 66px; object-fit: cover; display: block; }
.previews .pv .name { font-size: 9px; padding: 3px 4px; color: var(--muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.previews .pv .rm { position: absolute; top: 2px; right: 2px; background: rgba(0,0,0,.6); color: #fff; border: none; border-radius: 5px; width: 18px; height: 18px; cursor: pointer; font-size: 12px; line-height: 1; }

.actions { display: flex; gap: 10px; justify-content: flex-end; margin-top: 4px; }
.btn { font: inherit; font-weight: 700; font-size: 13.5px; border-radius: 10px; padding: 10px 18px; cursor: pointer; border: 1px solid var(--line); }
.btn.primary { background: var(--brand); color: #fff; border-color: var(--brand); }
.btn.primary:disabled { opacity: .55; cursor: default; }
.btn.ghost { background: transparent; color: var(--ink-soft); }
.formmsg { margin-top: 12px; font-size: 13px; text-align: right; min-height: 18px; }
.formmsg.err { color: var(--bad); }
.formmsg.ok { color: var(--good); }

.thanks { text-align: center; }
.thanks h2 { justify-content: center; }
.foot { margin-top: 30px; font: 11px/1.5 var(--mono); color: var(--muted); text-align: center; }

.progress { position: sticky; top: 0; z-index: 3; background: var(--bg); padding: 8px 0 10px; margin: -8px 0 14px; }
.progress .track { height: 6px; border-radius: 99px; background: var(--panel-2); overflow: hidden; }
.progress .track i { display: block; height: 100%; width: 0; background: var(--good); transition: width .25s; }
.progress .lbl { font: 600 11px/1 var(--mono); color: var(--muted); margin-top: 6px; }

/* Hướng dẫn công cụ test nhanh */
code { font: 12px/1 var(--mono); background: var(--panel-2); border: 1px solid var(--line); border-radius: 5px; padding: 1px 5px; }
.guide .guide-steps { margin: 4px 0 0; padding-left: 20px; font-size: 13px; color: var(--ink-soft); }
.guide .guide-steps > li { margin: 7px 0; }
.guide .guide-steps ul { margin: 5px 0; padding-left: 18px; }
.guide .guide-steps ul li { margin: 3px 0; }
.guide-note { margin: 14px 0 0; font-size: 12px; color: var(--ink-soft); background: color-mix(in srgb, var(--warn) 12%, transparent); border-left: 2px solid var(--warn); border-radius: 6px; padding: 8px 11px; }

/* Các bước thực hiện (trong mỗi tính năng) */
.steps { margin: 4px 0 10px; border: 1px solid var(--line); border-radius: 8px; background: var(--bg); }
.steps > summary { list-style: none; cursor: pointer; padding: 7px 10px; font: 700 9.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--good); }
.steps > summary::-webkit-details-marker { display: none; }
.steps > summary::before { content: "▸ "; }
.steps[open] > summary::before { content: "▾ "; }
.steps ol { margin: 0 0 8px; padding: 0 12px 0 30px; font-size: 12.5px; color: var(--ink-soft); }
.steps ol li { margin: 4px 0; }

/* Đánh giá UX/UI theo hạng mục */
.ux { border-top: 1px dashed var(--line); margin-top: 10px; padding-top: 12px; }
.ux .uxhead { font: 700 9.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin-bottom: 6px; }
.ux .uxhint { font-size: 11px; color: var(--muted); }
.ux textarea { margin-top: 8px; }
.catnote { margin-top: 12px; }

/* Mục tester tự thêm */
.addcustom { margin-top: 12px; width: 100%; font: inherit; font-size: 12.5px; font-weight: 700; color: var(--accent); background: transparent; border: 1px dashed var(--accent); border-radius: 9px; padding: 8px 10px; cursor: pointer; }
.addcustom:hover { background: color-mix(in srgb, var(--accent) 10%, transparent); }
.feat.custom { border-top: 1px solid var(--line); padding: 14px 0; }
.feat.custom .customname { font-weight: 700; font-size: 13.5px; margin: 0 0 8px; }
.feat.custom .rmcustom { font: inherit; font-size: 11px; font-weight: 700; color: var(--bad); background: transparent; border: 1px solid var(--line); border-radius: 7px; padding: 4px 10px; cursor: pointer; margin-left: auto; }
.customwrap:not(:empty) { margin-top: 4px; }
.customwrap .feat.custom::before { content: "＋ tự thêm"; display: inline-block; font: 700 9px/1 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--accent); border: 1px solid var(--accent); border-radius: 5px; padding: 2px 5px; margin-bottom: 6px; }