/* Skills directory, "Khối màu" — the 'new' arm of the skills experiment.
 * Loaded instead of page-technical-basics.css. Prefixed .sk2-.
 * House rules: radius 0, no shadow, no gradient, no translucency.
 */
body,.sk2-hero,.sk2-sec,.sk2-shout,.sk2-strip{
  --s2-ink:#0a0a0a; --s2-paper:#fff; --s2-dim:#6b7280; --s2-lab:#9aa1ab; --s2-hair:#e6e6e6;
  --s2-blue:#1a3aff; --s2-orange:#e8501e; --s2-green:#0f7a4a;
  --s2-font:'Be Vietnam Pro',system-ui,-apple-system,'Segoe UI',Roboto,sans-serif;
  --s2-pad:clamp(20px,5vw,72px);
}
.sk2-hero,.sk2-sec,.sk2-shout,.sk2-strip{font-family:var(--s2-font)}
.sk2-hero *,.sk2-sec *,.sk2-shout *,.sk2-strip *{box-sizing:border-box}
.sk2-in{max-width:1240px;margin:0 auto;padding-left:var(--s2-pad);padding-right:var(--s2-pad)}

.sk2-hero{background:var(--s2-blue);color:#fff;padding:clamp(38px,5.5vw,74px) 0}
.sk2-k{font-size:11px;letter-spacing:.2em;text-transform:uppercase;font-weight:700;
  color:rgba(255,255,255,.7)}
.sk2-h1{font-size:clamp(29px,5vw,58px);line-height:1.04;letter-spacing:-.05em;font-weight:800;
  margin:14px 0 0;color:#fff;max-width:18ch}
.sk2-lead{font-size:clamp(14.5px,1.6vw,18px);line-height:1.5;margin:16px 0 0;max-width:54ch;
  color:rgba(255,255,255,.88)}
.sk2-search-wrap{margin-top:24px;max-width:520px}
.sk2-search{width:100%;border:2px solid #fff;background:transparent;color:#fff;font-family:inherit;
  font-size:16px;font-weight:500;padding:13px 15px;height:50px;border-radius:0;
  -webkit-appearance:none;appearance:none}
.sk2-search::placeholder{color:rgba(255,255,255,.62)}
.sk2-search:focus{outline:3px solid #fff;outline-offset:2px}
.sk2-facts{display:flex;flex-wrap:wrap;margin-top:24px;border-top:1px solid rgba(255,255,255,.3)}
.sk2-facts > div{padding:14px 24px 14px 0;margin-right:24px;
  border-right:1px solid rgba(255,255,255,.22)}
.sk2-facts > div:last-child{border-right:0;margin-right:0}
.sk2-facts b{display:block;font-size:clamp(20px,2.6vw,30px);font-weight:800;letter-spacing:-.04em;
  line-height:1;color:#fff;font-variant-numeric:tabular-nums}
.sk2-facts span{display:block;font-size:10px;letter-spacing:.14em;text-transform:uppercase;
  font-weight:700;color:rgba(255,255,255,.72);margin-top:6px}

.sk2-shout{background:var(--s2-ink);color:#fff}
.sk2-shout-in{display:flex;align-items:center;justify-content:space-between;gap:20px;
  flex-wrap:wrap;padding-top:24px;padding-bottom:24px;text-decoration:none;color:#fff}
.sk2-shout-k{font-size:10px;letter-spacing:.18em;text-transform:uppercase;font-weight:700;
  color:rgba(255,255,255,.5)}
.sk2-shout-t{font-size:clamp(17px,2.2vw,26px);font-weight:800;letter-spacing:-.032em;
  margin-top:6px;line-height:1.2;color:#fff}
.sk2-shout-s{font-size:13.5px;color:rgba(255,255,255,.7);margin-top:6px;max-width:60ch}
.sk2-shout-go{font-size:14px;font-weight:800;white-space:nowrap;color:#fff}
.sk2-shout-in:hover .sk2-shout-t{text-decoration:underline;text-underline-offset:5px}

.sk2-sec{padding:clamp(38px,5vw,72px) 0;background:var(--s2-paper)}
.sk2-group{margin-bottom:clamp(30px,4vw,52px)}
.sk2-group[hidden]{display:none}
.sk2-group-h{display:flex;align-items:baseline;gap:12px;margin-bottom:16px;
  border-bottom:2px solid var(--s2-ink);padding-bottom:10px}
.sk2-group-h h2{font-size:clamp(19px,2.4vw,28px);font-weight:800;letter-spacing:-.035em;margin:0;
  color:var(--s2-ink)}
.sk2-group-h span{font-size:10.5px;letter-spacing:.14em;text-transform:uppercase;font-weight:700;
  color:var(--s2-lab)}
.sk2-grid{display:grid;grid-template-columns:1fr;border-left:2px solid var(--s2-ink);
  border-top:2px solid var(--s2-ink)}
@media (min-width:640px){ .sk2-grid{grid-template-columns:1fr 1fr} }
@media (min-width:1040px){ .sk2-grid{grid-template-columns:repeat(3,1fr)} }
.sk2-card{position:relative;display:block;padding:16px 18px 18px;text-decoration:none;
  color:var(--s2-ink);border-right:2px solid var(--s2-ink);border-bottom:2px solid var(--s2-ink)}
.sk2-card[hidden]{display:none}
.sk2-card:hover{background:var(--s2-ink)}
.sk2-card-n{display:block;font-size:15.5px;font-weight:800;letter-spacing:-.028em;line-height:1.25;
  color:var(--s2-ink)}
.sk2-card-d{display:block;font-size:12.5px;line-height:1.5;color:var(--s2-dim);margin-top:7px}
.sk2-card-seen{display:inline-block;font-size:9.5px;letter-spacing:.14em;text-transform:uppercase;
  font-weight:700;color:var(--s2-green);margin-top:9px}
.sk2-card.is-seen{background:#fafafa}
.sk2-card:hover .sk2-card-n{color:#fff}
.sk2-card:hover .sk2-card-d{color:rgba(255,255,255,.75)}
.sk2-card:hover .sk2-card-seen{color:rgba(255,255,255,.6)}
.sk2-empty{border:2px solid var(--s2-ink);padding:26px;font-size:14.5px;color:var(--s2-dim)}
.sk2-empty[hidden]{display:none}

.sk2-btn{display:inline-block;padding:14px 26px;font-weight:800;font-size:14.5px;
  text-decoration:none;border:2px solid #fff;background:#fff;color:var(--s2-ink);border-radius:0;
  font-family:inherit;line-height:1.2}
.sk2-btn:hover{background:#f0f0f0;border-color:#f0f0f0}
.sk2-strip{background:var(--s2-orange);color:#fff;padding:clamp(28px,4vw,50px) 0}
.sk2-strip-in{display:flex;gap:22px;align-items:center;justify-content:space-between;flex-wrap:wrap}
.sk2-strip-t{font-size:clamp(19px,2.6vw,32px);font-weight:800;letter-spacing:-.032em;
  line-height:1.15;margin:0;color:#fff;max-width:26ch}
.sk2-strip-s{font-size:13.5px;line-height:1.55;color:rgba(255,255,255,.86);margin:8px 0 0;
  max-width:54ch}

/* ── defensive: design-system.css owns bare a / a:hover ── */
.sk2-layout a.sk2-card,.sk2-layout a.sk2-card:link,.sk2-layout a.sk2-card:visited{
  color:var(--s2-ink);text-decoration:none}
.sk2-layout a.sk2-card:hover .sk2-card-n{color:#fff}
.sk2-layout a.sk2-card:hover .sk2-card-d{color:rgba(255,255,255,.75)}
.sk2-layout a.sk2-shout-in,.sk2-layout a.sk2-shout-in:hover{color:#fff;text-decoration:none}
.sk2-layout a.sk2-btn,.sk2-layout a.sk2-btn:hover{color:var(--s2-ink);text-decoration:none}
.sk2-layout .sk2-h1,.sk2-layout .sk2-strip-t,.sk2-layout .sk2-shout-t{color:#fff}
.sk2-layout .sk2-lead{color:rgba(255,255,255,.88)}
.sk2-layout .sk2-strip-s{color:rgba(255,255,255,.86)}
.sk2-layout .sk2-group-h h2{color:var(--s2-ink)}
.sk2-layout .sk2-group-h span,.sk2-layout .sk2-card-d{color:var(--s2-lab)}
.sk2-layout .sk2-card-d{color:var(--s2-dim)}