/* Kiên Trì Luyện Tập Ngoại Ngữ — trang tổng. Giao diện tối giản, dịu mắt. */
:root{--bg:#f7f6f3;--card:#fff;--text:#1f2328;--muted:#5b616b;--line:#e3e1dc;--accent:#2f6f73;--accent-soft:#e6f0f0;--accent-text:#245a5d;--bar:#d9dcd8}
.dark{--bg:#1f2124;--card:#272a2e;--text:#e6e4df;--muted:#a3a8ae;--line:#383c41;--accent:#6fb3b1;--accent-soft:#2c3a3b;--accent-text:#8fcac7;--bar:#3a3e43}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.65 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;-webkit-font-smoothing:antialiased}
a{color:var(--accent-text)}
.skip{position:absolute;left:-999px;top:8px;background:var(--card);padding:8px 12px;border:1px solid var(--line);border-radius:6px;z-index:10}
.skip:focus{left:8px}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.nav{max-width:1080px;margin:0 auto;padding:18px 20px;display:flex;align-items:center;justify-content:space-between;gap:12px;border-bottom:1px solid var(--line)}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);font-weight:600;font-size:1rem}
.logo{width:30px;height:30px;border-radius:6px;background:var(--accent);color:var(--bg);display:grid;place-items:center;font-weight:700;font-size:.95rem}
.icon-btn{font:inherit;font-size:.875rem;color:var(--text);background:transparent;border:1px solid var(--line);border-radius:6px;padding:6px 12px;cursor:pointer}
.icon-btn:hover{border-color:var(--muted)}
main{max-width:1080px;margin:0 auto;padding:0 20px}
.hero{padding:64px 0 48px;max-width:720px}
.eyebrow{margin:0 0 10px;color:var(--accent-text);font-size:.875rem;font-weight:600;letter-spacing:.02em}
.hero h1{margin:0 0 16px;font-size:clamp(1.9rem,4.2vw,2.75rem);line-height:1.2;font-weight:700;letter-spacing:-.01em}
.lead{margin:0 0 28px;color:var(--muted);font-size:1.075rem}
.lead b{color:var(--text);font-weight:600}
.bignums{display:flex;flex-wrap:wrap;gap:12px 40px;margin:0 0 32px}
.bignums div{display:flex;flex-direction:column}
.bignums b{font-size:1.6rem;font-weight:700;font-variant-numeric:tabular-nums}
.bignums span{color:var(--muted);font-size:.875rem}
.cta{display:inline-block;background:var(--accent);color:#fff;text-decoration:none;font-weight:600;padding:10px 20px;border-radius:6px}
.dark .cta{color:#14201f}
.cta:hover{filter:brightness(.95)}
.langs{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;padding:8px 0 48px}
.lang{position:relative;background:var(--card);border:1px solid var(--line);border-radius:10px;padding:22px 22px 20px;display:flex;flex-direction:column;gap:10px;transition:border-color .15s}
.lang:hover,.lang:focus-within{border-color:var(--accent)}
.lang-link{position:absolute;inset:0;z-index:1;border-radius:10px}
.lang-top{display:flex;align-items:center;justify-content:space-between;gap:8px;flex-wrap:wrap}
.flag{font-weight:700;font-size:1.15rem}
.greet{margin:0;font-size:1.05rem;color:var(--accent-text)}
.greet small{margin-left:8px;color:var(--muted);font-size:.85rem}
.desc{margin:0;color:var(--muted);font-size:.94rem}
.nums{list-style:none;margin:4px 0 0;padding:0;display:flex;flex-wrap:wrap;gap:4px 18px;font-size:.9rem;color:var(--muted)}
.nums b{color:var(--text);font-weight:600;font-variant-numeric:tabular-nums}
.tracks{display:flex;flex-wrap:wrap;gap:6px}
.tracks span{font-size:.78rem;padding:2px 8px;border:1px solid var(--line);border-radius:4px;color:var(--muted)}
.tracks i{font-style:normal;opacity:.75}
.go{margin-top:auto;padding-top:6px;font-weight:600;font-size:.92rem;color:var(--accent-text)}
.prog{font-size:.84rem;color:var(--muted);border-top:1px solid var(--line);padding-top:10px}
.prog.empty{font-style:normal}
.ph{display:flex;justify-content:space-between;margin-bottom:6px;color:var(--text)}
.bar{height:6px;border-radius:3px;background:var(--bar);overflow:hidden}
.bar i{display:block;height:100%;width:0;background:var(--accent);transition:width .6s ease}
.pm{display:flex;flex-wrap:wrap;gap:2px 14px;margin-top:8px}
.sumbar{background:var(--accent-soft);border:1px solid var(--line);border-radius:10px;padding:14px 18px;margin:0 0 48px;font-size:.95rem}
.features{padding:8px 0 56px;border-top:1px solid var(--line)}
.features h2{font-size:1.25rem;font-weight:700;margin:40px 0 20px}
.fgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:28px 32px}
.feat h3{margin:0 0 6px;font-size:1rem;font-weight:600}
.feat p{margin:0;color:var(--muted);font-size:.93rem}
kbd{font:600 .8em ui-monospace,monospace;border:1px solid var(--line);border-radius:4px;padding:0 5px;background:var(--bg)}
.foot{max-width:1080px;margin:0 auto;padding:28px 20px 80px;border-top:1px solid var(--line);color:var(--muted);font-size:.85rem}
.foot p{margin:0 0 10px}
.foot b{color:var(--text);font-weight:600}
.cred{font-size:.78rem;line-height:1.6}
.cred a{color:var(--muted)}
@media (max-width:600px){.hero{padding:40px 0 32px}.langs{grid-template-columns:1fr}.nav{padding:14px 16px}main{padding:0 16px}.brand span:last-child{font-size:.92rem}}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
/* paywall trên trang tổng: nút mở khóa nằm trong header */
.nav-actions{display:flex;align-items:center;gap:8px}
#pwSlot{display:contents}
.pw-pill.pw-inline{position:static!important;inset:auto!important;z-index:auto!important;font:inherit!important;font-size:.875rem!important;font-weight:500!important;padding:6px 12px!important;border-radius:6px!important;background:transparent!important;color:var(--accent-text)!important;border:1px solid var(--accent)!important;box-shadow:none!important;white-space:nowrap}
.pw-pill.pw-inline:hover{background:var(--accent-soft)!important}
@media (max-width:600px){.pw-pill.pw-inline{font-size:.8rem!important;padding:5px 9px!important}.brand span:last-child{font-size:.82rem}.logo{width:26px;height:26px}}
@media (max-width:380px){.brand span:last-child{display:none}}
.pw-hubbadge{align-self:flex-start;background:transparent!important;border:1px solid var(--line);color:var(--muted)!important;border-radius:4px!important;font-weight:600!important;margin-top:0!important}
.pw-hubbadge.own{color:var(--accent-text)!important;border-color:var(--accent)}