:root{--background:#f7f8f5;--foreground:#1b1d18;--card:#ffffff;--card-2:#eef0ea;--border:#dadcd3;--muted-foreground:#5c6257;--primary:#2f6b34;--primary-foreground:#ffffff;--primary-soft:#e2ecd9;--warn:#8f5a00;}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){--background:#12140f;--foreground:#e8ebe2;--card:#191c15;--card-2:#20241a;--border:#2d3226;--muted-foreground:#9aa090;--primary:#9cc088;--primary-foreground:#12140f;--primary-soft:#232d1e;--warn:#e0b055;}}
:root[data-theme="dark"]{--background:#12140f;--foreground:#e8ebe2;--card:#191c15;--card-2:#20241a;--border:#2d3226;--muted-foreground:#9aa090;--primary:#9cc088;--primary-foreground:#12140f;--primary-soft:#232d1e;--warn:#e0b055;}
:root[data-pal="teal"]{--background:#f6f8f8;--foreground:#171c1b;--card:#ffffff;--card-2:#edf1f0;--border:#d8dedd;--muted-foreground:#586462;--primary:#1f6f66;--primary-foreground:#ffffff;--primary-soft:#dcece9;--warn:#8f5a00;}
@media (prefers-color-scheme:dark){:root[data-pal="teal"]:not([data-theme="light"]){--background:#111514;--foreground:#e6eceb;--card:#171c1b;--card-2:#1d2322;--border:#2a3230;--muted-foreground:#93a09d;--primary:#6cc4b4;--primary-foreground:#0d1a17;--primary-soft:#1c2b28;--warn:#e0b055;}}
:root[data-pal="teal"][data-theme="dark"]{--background:#111514;--foreground:#e6eceb;--card:#171c1b;--card-2:#1d2322;--border:#2a3230;--muted-foreground:#93a09d;--primary:#6cc4b4;--primary-foreground:#0d1a17;--primary-soft:#1c2b28;--warn:#e0b055;}
:root[data-pal="sun"]{--background:#f9f8f3;--foreground:#1d1c16;--card:#ffffff;--card-2:#f0eee3;--border:#dedbcc;--muted-foreground:#625f52;--primary:#7d6200;--primary-foreground:#ffffff;--primary-soft:#f1e8bf;--warn:#8f4a00;}
@media (prefers-color-scheme:dark){:root[data-pal="sun"]:not([data-theme="light"]){--background:#14130e;--foreground:#ece9dc;--card:#1b1a13;--card-2:#22201a;--border:#302e24;--muted-foreground:#a09c8a;--primary:#e2c455;--primary-foreground:#14130e;--primary-soft:#2b2712;--warn:#e89a5a;}}
:root[data-pal="sun"][data-theme="dark"]{--background:#14130e;--foreground:#ece9dc;--card:#1b1a13;--card-2:#22201a;--border:#302e24;--muted-foreground:#a09c8a;--primary:#e2c455;--primary-foreground:#14130e;--primary-soft:#2b2712;--warn:#e89a5a;}
:root[data-pal="lav"]{--background:#f8f7fb;--foreground:#1c1b22;--card:#ffffff;--card-2:#efedf5;--border:#dddbe7;--muted-foreground:#5f5c6d;--primary:#5b4fc4;--primary-foreground:#ffffff;--primary-soft:#e7e4f8;--warn:#8f5a00;}
@media (prefers-color-scheme:dark){:root[data-pal="lav"]:not([data-theme="light"]){--background:#131218;--foreground:#eae9f1;--card:#191820;--card-2:#1f1e28;--border:#2d2c39;--muted-foreground:#9c99ad;--primary:#b2a9f2;--primary-foreground:#131218;--primary-soft:#26233d;--warn:#e0b055;}}
:root[data-pal="lav"][data-theme="dark"]{--background:#131218;--foreground:#eae9f1;--card:#191820;--card-2:#1f1e28;--border:#2d2c39;--muted-foreground:#9c99ad;--primary:#b2a9f2;--primary-foreground:#131218;--primary-soft:#26233d;--warn:#e0b055;}
:root[data-pal="mono"]{--background:#f7f7f6;--foreground:#171717;--card:#ffffff;--card-2:#eeeeec;--border:#d9d9d6;--muted-foreground:#5e5e5b;--primary:#171717;--primary-foreground:#ffffff;--primary-soft:#e7e7e4;--warn:#8f5a00;}
@media (prefers-color-scheme:dark){:root[data-pal="mono"]:not([data-theme="light"]){--background:#121212;--foreground:#eeeeee;--card:#191919;--card-2:#202020;--border:#2e2e2e;--muted-foreground:#9a9a9a;--primary:#eeeeee;--primary-foreground:#121212;--primary-soft:#262626;--warn:#e0b055;}}
:root[data-pal="mono"][data-theme="dark"]{--background:#121212;--foreground:#eeeeee;--card:#191919;--card-2:#202020;--border:#2e2e2e;--muted-foreground:#9a9a9a;--primary:#eeeeee;--primary-foreground:#121212;--primary-soft:#262626;--warn:#e0b055;}
/* ---------- base ---------- */
:root{
  --f-serif:'Newsreader',Georgia,'Times New Roman',serif;
  --f-sans:'Be Vietnam Pro',system-ui,-apple-system,'Segoe UI',Roboto,sans-serif;
  --f-mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  --ease:cubic-bezier(.3,.7,.2,1);
  --phone:#10120e;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:72px;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--background);color:var(--foreground);font:400 16px/1.65 var(--f-sans);-webkit-font-smoothing:antialiased}
[hidden]{display:none!important}
h1,h2,h3,h4,p,ul,ol,dl,dd,figure{margin:0}
ul,ol{padding:0;list-style:none}
a{color:inherit}
button{font:inherit;color:inherit;cursor:pointer}
svg{display:block}
code,kbd{font-family:var(--f-mono);font-size:.88em}
code{background:var(--card-2);padding:.1em .4em;border-radius:5px}
kbd{border:1px solid var(--border);border-bottom-width:2px;border-radius:5px;padding:0 .4em;background:var(--card)}
:focus-visible{outline:2px solid var(--primary);outline-offset:2px;border-radius:4px}
.wrap{width:100%;max-width:1080px;margin:0 auto;padding:0 20px}

h1,h2,.feat h3{font-family:var(--f-serif);font-weight:600;letter-spacing:-.012em;text-wrap:balance}
h1{font-size:clamp(2.1rem,5vw,3.5rem);line-height:1.08;max-width:21ch}
h2{font-size:clamp(1.65rem,3.2vw,2.15rem);line-height:1.15}
.feat h3{font-size:1.5rem;line-height:1.2}
h3,h4{font-weight:600;line-height:1.35}
.sub{color:var(--muted-foreground);max-width:58ch;margin-top:10px}

/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:44px;padding:0 20px;border:1px solid var(--primary);border-radius:8px;background:var(--primary);color:var(--primary-foreground);font-weight:600;font-size:.95rem;text-decoration:none;transition:background-color .15s,border-color .15s;white-space:nowrap}
.btn:hover{background:color-mix(in srgb,var(--primary) 88%,var(--foreground))}
.btn.plain{background:transparent;color:var(--foreground);border-color:var(--border)}
.btn.plain:hover{background:var(--card-2)}
.btn.sm{min-height:36px;padding:0 14px;font-size:.88rem}
.btn:disabled{opacity:.45;cursor:default}
.link{background:none;border:0;padding:0;color:var(--primary);text-decoration:underline;text-underline-offset:3px;font-size:.9rem}
.actions{display:flex;flex-wrap:wrap;gap:12px}
.note{color:var(--muted-foreground);font-size:.9rem}

/* ---------- header ---------- */
.site-head{position:sticky;top:0;z-index:20;background:var(--background);border-bottom:1px solid var(--border)}
.bar{display:flex;align-items:center;gap:24px;height:60px}
.brand{display:inline-flex;align-items:center;gap:10px;font-weight:700;text-decoration:none;font-size:1.05rem}
.nav{display:flex;gap:22px;margin-left:8px}
.nav a{color:var(--muted-foreground);text-decoration:none;font-size:.92rem;white-space:nowrap}
.nav a:hover{color:var(--foreground)}
.tools{display:flex;align-items:center;gap:8px;margin-left:auto}
.ghost-btn{display:inline-flex;align-items:center;gap:8px;height:36px;padding:0 10px;border:1px solid var(--border);background:transparent;border-radius:8px;color:var(--muted-foreground)}
.ghost-btn:hover{color:var(--foreground);background:var(--card-2)}
.ghost-btn kbd{white-space:nowrap;font-size:.72rem;border:0;background:none;padding:0}
.lang{display:flex;border:1px solid var(--border);border-radius:8px;overflow:hidden}
.lang button{border:0;background:transparent;height:34px;padding:0 10px;font-size:.8rem;font-weight:600;color:var(--muted-foreground)}
.lang button[aria-pressed="true"]{background:var(--foreground);color:var(--background)}
.login{white-space:nowrap;font-size:.92rem;text-decoration:none;color:var(--muted-foreground);padding:0 6px}
.login:hover{color:var(--foreground)}

/* ---------- hero ---------- */
.hero{padding-top:72px;padding-bottom:40px}
.kicker{color:var(--primary);font-weight:600;font-size:.92rem;margin-bottom:14px}
.lead{font-size:1.15rem;color:var(--muted-foreground);max-width:56ch;margin:20px 0 28px}
.hero .note{margin-top:14px}

/* ---------- product window ---------- */
.win{border:1px solid var(--border);border-radius:12px;background:var(--card);overflow:hidden;margin-bottom:8px}
.chrome{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 16px;border-bottom:1px solid var(--border);background:var(--card-2);font-size:.82rem;color:var(--muted-foreground)}
.addr{font-family:var(--f-mono)}
.tag{display:inline-block;padding:2px 10px;border:1px solid var(--border);border-radius:99px;font-size:.78rem;color:var(--muted-foreground);white-space:nowrap}
/* "Sắp có": a tag on things that are planned, not shipped. */
.tag.soon{border-color:var(--warn);color:var(--warn)}
h3 .tag.soon{margin-left:8px;vertical-align:middle;font-weight:500}
.app{display:grid;grid-template-columns:208px 1fr;min-height:430px}
.side{position:relative;display:flex;flex-direction:column;gap:2px;padding:12px;border-right:1px solid var(--border)}
.ind{position:absolute;left:0;top:0;border-radius:8px;background:var(--primary-soft);transition:transform .28s var(--ease),width .28s var(--ease),height .28s var(--ease);pointer-events:none}
.tab{position:relative;display:flex;align-items:center;gap:10px;padding:9px 12px;border:0;background:none;border-radius:8px;text-align:left;font-size:.92rem;color:var(--muted-foreground);white-space:nowrap}
.tab svg{width:18px;height:18px;flex:none}
.tab[aria-selected="true"]{color:var(--foreground);font-weight:600}
.tab:hover{color:var(--foreground)}
.streak{margin-top:auto;padding:14px 12px 4px;font-size:.82rem;color:var(--muted-foreground);display:flex;flex-direction:column;gap:2px}
.streak b{font-size:1.15rem;color:var(--foreground)}
.meter{height:5px;border-radius:9px;background:var(--card-2);margin:6px 0;overflow:hidden}
.meter i{display:block;width:70%;height:100%;background:var(--primary)}
.pane{padding:22px 24px;min-width:0}
.panel{display:flex;flex-direction:column;gap:12px}
.panel-h{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:6px;flex-wrap:wrap}
.panel-h h3{font-size:1.02rem}

.msg{max-width:min(520px,92%);padding:10px 14px;border-radius:12px;font-size:.94rem;line-height:1.55;display:flex;flex-direction:column;gap:2px}
.msg b{font-size:.76rem;font-weight:600;color:var(--muted-foreground)}
.msg.me{align-self:flex-end;background:var(--primary-soft)}
.msg.ai{align-self:flex-start;background:var(--card-2)}
#p-tutor .msg{opacity:0;transform:translateY(6px);transition:opacity .35s,transform .35s var(--ease)}
#p-tutor .msg.on,.msg.shown{opacity:1;transform:none}
.typing{align-self:flex-start;display:flex;gap:4px;padding:14px 16px;border-radius:12px;background:var(--card-2)}
.typing i{width:6px;height:6px;border-radius:50%;background:var(--muted-foreground);animation:blink 1s infinite}
.typing i:nth-child(2){animation-delay:.15s}.typing i:nth-child(3){animation-delay:.3s}
@keyframes blink{0%,80%,100%{opacity:.25}40%{opacity:1}}
.acts{display:flex;gap:8px;flex-wrap:wrap}
.act{padding:5px 12px;border:1px solid var(--border);border-radius:99px;font-size:.84rem;color:var(--muted-foreground)}
.foot-note{font-size:.84rem;color:var(--muted-foreground)}
.composer{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:auto;padding:8px 8px 8px 14px;border:1px solid var(--border);border-radius:10px;color:var(--muted-foreground);font-size:.92rem;background:var(--background)}
.send{display:grid;place-items:center;width:32px;height:32px;border-radius:8px;background:var(--primary);color:var(--primary-foreground);flex:none}

.steps{display:flex;flex-direction:column;gap:14px}
.steps li{display:flex;gap:12px;align-items:flex-start}
.steps .n{display:grid;place-items:center;flex:none;width:24px;height:24px;border-radius:50%;background:var(--primary-soft);color:var(--primary);font-size:.78rem;font-weight:700;margin-top:1px}
.steps small{display:block;color:var(--muted-foreground);font-size:.86rem;margin-top:2px}
.steps b{font-weight:600}

.week{display:grid;grid-template-columns:repeat(auto-fill,minmax(104px,1fr));gap:10px}
.day h4{font-size:.8rem;color:var(--muted-foreground);font-weight:600;margin-bottom:6px}
.chip{padding:8px 10px;border-radius:8px;background:var(--card-2);font-size:.84rem;line-height:1.35;margin-bottom:6px}
.chip small{display:block;color:var(--muted-foreground);font-size:.76rem}
.chip.soft{background:var(--primary-soft)}
.chip.warn{background:transparent;border:1px solid var(--warn);}
.fcard{padding:22px;border:1px solid var(--border);border-radius:10px;background:var(--background);display:flex;flex-direction:column;gap:8px}
.fcard p{font-family:var(--f-serif);font-size:1.3rem;line-height:1.35}
.fcard small,.rate small{color:var(--muted-foreground);font-size:.8rem}
.rate{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}
.rate div{padding:10px 12px;border:1px solid var(--border);border-radius:8px;display:flex;flex-direction:column;font-size:.9rem}
.bars{display:flex;flex-direction:column;gap:12px}
.bar-row{display:grid;grid-template-columns:88px 1fr 40px;align-items:center;gap:12px;font-size:.9rem}
.bar-row b{text-align:right;font-weight:600}
/* Level names instead of percentages: the value column needs more room. */
.bars.levels .bar-row{grid-template-columns:96px 1fr 104px}
.bars.levels .bar-row b{font-size:.82rem;white-space:nowrap}
.track{height:8px;border-radius:9px;background:var(--card-2);overflow:hidden}
.track i{display:block;height:100%;background:var(--primary);transform-origin:left;animation:grow .7s var(--ease) both}
.track i.low{background:var(--warn)}
@keyframes grow{from{transform:scaleX(0)}}

/* ---------- sections ---------- */
.sec{padding-top:88px}
.sec>h2+*{margin-top:28px}
.sec>h2+.sub{margin-top:10px}
.sec>.sub+*{margin-top:28px}

.rows{border-top:1px solid var(--border)}
.row{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.2fr) minmax(0,1.2fr);gap:8px 32px;padding:22px 0;border-bottom:1px solid var(--border)}
.row p{color:var(--muted-foreground)}
.row .fix{color:var(--foreground)}
.fix b{color:var(--primary)}

.feat{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.1fr);gap:48px;align-items:start;padding:40px 0;border-bottom:1px solid var(--border)}
.feat:first-of-type{padding-top:8px}
.feat:last-child{border-bottom:0}
.feat .txt>p{color:var(--muted-foreground);margin:12px 0 18px}
.dash li{position:relative;padding-left:20px;margin-top:8px}
.dash li::before{content:"–";position:absolute;left:0;color:var(--primary);font-weight:700}
.demo{border:1px solid var(--border);border-radius:12px;background:var(--card);padding:20px;min-width:0}
.demo .prompt{font-family:var(--f-mono);font-size:.92rem;margin:14px 0 14px;padding-bottom:12px;border-bottom:1px solid var(--border)}
.demo .steps{gap:12px}

.seg{position:relative;display:inline-flex;padding:4px;border:1px solid var(--border);border-radius:9px;background:var(--card-2);max-width:100%}
.seg button{position:relative;z-index:1;border:0;background:none;padding:7px 14px;border-radius:6px;font-size:.88rem;color:var(--muted-foreground);white-space:nowrap}
.seg button[aria-pressed="true"]{color:var(--foreground);font-weight:600}
.seg .pill{position:absolute;left:4px;top:4px;bottom:4px;width:0;border-radius:6px;background:var(--background);box-shadow:0 0 0 1px var(--border);transition:transform .25s var(--ease),width .25s var(--ease)}

.swapbox{transition:opacity .2s}
.swapbox.swap{opacity:0}
.ladder{display:flex;align-items:center;flex-wrap:wrap;gap:8px 12px;margin-top:14px;font-size:.88rem;color:var(--muted-foreground)}
.dots{display:flex;gap:4px}
.dots i{width:22px;height:5px;border-radius:9px;background:var(--border);transition:background-color .25s}
.dots i.on{background:var(--primary)}
.verdict{margin-top:14px;padding:10px 14px;border-left:3px solid var(--primary);background:var(--primary-soft);border-radius:0 8px 8px 0;font-size:.9rem}
.verdict.no{border-left-color:var(--warn);background:color-mix(in srgb,var(--warn) 14%,transparent)}
.verdict b{display:block}

.curve{width:100%;height:auto;overflow:visible}
.curve text{fill:var(--muted-foreground);font:11px var(--f-sans)}
.curve .gl{stroke:var(--border);stroke-width:1}
.curve .ax{stroke:var(--muted-foreground);fill:none;stroke-width:1}
.curve .c1{fill:none;stroke:var(--muted-foreground);stroke-width:2;stroke-dasharray:5 4}
.curve .c2{fill:none;stroke:var(--primary);stroke-width:2.5;stroke-linejoin:round}
.curve .pt{fill:var(--background);stroke:var(--primary);stroke-width:2}
.legend{display:flex;flex-wrap:wrap;gap:6px 18px;font-size:.84rem;margin:8px 0 8px;color:var(--muted-foreground)}
.legend span{display:inline-flex;align-items:center;gap:8px}
.legend i{width:18px;height:0;border-top:2px solid}
.legend .k1{border-top-style:dashed;border-color:var(--muted-foreground)}
.legend .k2{border-color:var(--primary)}

/* devices */
.dev{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:56px;align-items:center}
.phones{display:flex;justify-content:center;gap:28px}
.pw{display:flex;flex-direction:column;align-items:center;gap:10px;opacity:.5;transition:opacity .3s}
.pw.cur{opacity:1}
.pw figcaption{font-size:.82rem;color:var(--muted-foreground)}
.dev .txt>p{color:var(--muted-foreground);margin:12px 0 20px}
.dev .steps{margin:20px 0 12px}

/* principles, layers, road, facts */
.pairs{display:grid;grid-template-columns:1fr 1fr;gap:0 48px}
.pairs>div{padding:20px 0;border-top:1px solid var(--border)}
.pairs dd{color:var(--muted-foreground);margin-top:4px}
.layers{border-top:1px solid var(--border)}
.layers li{display:grid;grid-template-columns:180px minmax(0,1fr) auto;gap:8px 32px;align-items:baseline;padding:18px 0;border-bottom:1px solid var(--border)}
.layers p{color:var(--muted-foreground)}
.layers code{white-space:nowrap}
.plainlist{margin-top:24px}
.road{display:grid;grid-template-columns:repeat(4,1fr);gap:0 28px;border-top:1px solid var(--border)}
.road li{padding:18px 0;display:flex;flex-direction:column;gap:6px}
.road p{color:var(--muted-foreground);font-size:.94rem}
.st{font-size:.82rem;color:var(--muted-foreground);margin-top:4px}
.st.on{color:var(--primary);font-weight:600}
.facts{display:grid;grid-template-columns:repeat(auto-fit,minmax(190px,1fr));gap:0 28px;margin-top:24px}
.facts>div{padding:14px 0;border-top:1px solid var(--border)}
.facts dt{font-size:.84rem;color:var(--muted-foreground)}
.facts dd{font-weight:600}
#du-an p:last-child{margin-top:24px}

/* faq */
.faq{border-top:1px solid var(--border);max-width:760px}
.qa{border-bottom:1px solid var(--border)}
.q{display:flex;width:100%;justify-content:space-between;align-items:center;gap:16px;padding:16px 0;border:0;background:none;text-align:left;font-weight:600}
.q::after{content:"+";flex:none;font-weight:400;font-size:1.3rem;line-height:1;color:var(--muted-foreground);transition:transform .25s var(--ease)}
.qa.open .q::after{transform:rotate(45deg)}
.a{display:grid;grid-template-rows:0fr;transition:grid-template-rows .3s var(--ease)}
.a>div{overflow:hidden}
.a p{padding-bottom:18px;color:var(--muted-foreground);max-width:62ch}
.qa.open .a{grid-template-rows:1fr}

.final{padding:44px 0;border-top:1px solid var(--border)}
.final p{color:var(--muted-foreground);margin:10px 0 22px}
.final .note{margin:16px 0 0}
.final .note a{color:var(--primary)}

/* data safety */
.safe{display:grid;grid-template-columns:1fr 1fr;gap:32px}
.safe h3{font-size:1.05rem;padding-bottom:10px;border-bottom:2px solid var(--primary)}
.safe .no h3{border-bottom-color:var(--muted-foreground)}
.safe small{display:block;color:var(--muted-foreground);font-size:.86rem;margin-top:8px}
.safe li{padding:14px 0;border-bottom:1px solid var(--border)}
.safe li b{display:block;font-weight:600}
.safe li span{color:var(--muted-foreground);font-size:.94rem}
.safe-note{margin-top:28px;padding:16px 18px;border:1px solid var(--border);border-radius:10px;background:var(--card);font-size:.94rem;max-width:78ch}
.safe-note p+p{margin-top:8px;color:var(--muted-foreground)}
.safe-note a{color:var(--primary)}

/* legal */
.legal-wrap{display:grid;grid-template-columns:210px minmax(0,1fr);gap:40px;margin-top:24px}
.toc{position:sticky;top:84px;align-self:start;display:flex;flex-direction:column;gap:6px;font-size:.88rem}
.toc a{color:var(--muted-foreground);text-decoration:none;padding:2px 0}
.toc a:hover{color:var(--foreground)}
.toc strong{font-size:.82rem;margin-bottom:4px}
.doc{max-width:70ch}
.doc .dt{font-family:var(--f-serif);font-size:1.5rem}
.doc .dm{color:var(--muted-foreground);font-size:.88rem;margin:4px 0 18px}
.doc h4{font-size:1.02rem;margin:26px 0 8px}
.doc p{margin-bottom:10px;color:var(--muted-foreground)}
.doc ul{margin:0 0 10px}
.doc li{position:relative;padding-left:18px;margin-bottom:6px;color:var(--muted-foreground)}
.doc li::before{content:"–";position:absolute;left:0}

/* footer */
.site-foot{margin-top:96px;border-top:1px solid var(--border);padding:40px 0 32px;font-size:.92rem}
.fgrid{display:grid;grid-template-columns:1.5fr repeat(4,1fr);gap:28px}
.fabout p{color:var(--muted-foreground);margin-top:10px;max-width:34ch}
.fgrid h4{font-size:.88rem;margin-bottom:10px}
.fgrid li{margin-bottom:6px}
.fgrid li a{color:var(--muted-foreground);text-decoration:none}
.fgrid li a:hover{color:var(--foreground);text-decoration:underline}
.fbase{display:flex;flex-wrap:wrap;gap:10px 28px;justify-content:space-between;align-items:center;margin-top:36px;padding-top:20px;border-top:1px solid var(--border);color:var(--muted-foreground);font-size:.84rem}
#foot-legal a{color:var(--muted-foreground)}
#foot-legal a+a{margin-left:16px}
.pal-pick{display:flex;align-items:center;gap:10px}
#pal-opts{display:flex;gap:6px}
#pal-opts button{width:22px;height:22px;padding:0;border-radius:50%;border:2px solid transparent;background-clip:padding-box;outline:1px solid var(--border);outline-offset:0}
#pal-opts button[aria-pressed="true"]{outline:2px solid var(--foreground);outline-offset:2px}

/* toast + command palette */
.toast{position:fixed;left:50%;bottom:24px;z-index:60;transform:translate(-50%,12px);max-width:calc(100vw - 32px);padding:10px 16px;border-radius:9px;background:var(--foreground);color:var(--background);font-size:.9rem;opacity:0;pointer-events:none;transition:opacity .2s,transform .25s var(--ease)}
.toast.on{opacity:1;transform:translate(-50%,0)}
.cmd{position:fixed;inset:0;z-index:50;display:flex;align-items:flex-start;justify-content:center;padding:14vh 16px 16px;background:rgba(10,12,8,.5)}
.cbox{width:100%;max-width:520px;border:1px solid var(--border);border-radius:12px;background:var(--card);overflow:hidden;box-shadow:0 20px 50px rgba(0,0,0,.3)}
.cbox input{width:100%;border:0;border-bottom:1px solid var(--border);background:none;padding:14px 16px;font:inherit;color:inherit;outline:0}
.clist{max-height:320px;overflow:auto;padding:6px}
.clist li{display:flex;justify-content:space-between;gap:12px;padding:9px 10px;border-radius:7px;cursor:pointer;font-size:.92rem}
.clist li small{color:var(--muted-foreground)}
.clist li[aria-selected="true"]{background:var(--primary-soft)}
.cfoot{display:flex;gap:16px;padding:9px 14px;border-top:1px solid var(--border);font-size:.76rem;color:var(--muted-foreground)}

/* ---------- responsive ---------- */
@media (max-width:1360px){#open-pal{display:none}.nav{gap:16px}}
@media (max-width:1100px){.nav{display:none}.menu-btn{display:inline-flex}}
@media (max-width:900px){
  .row{grid-template-columns:1fr}
  .feat,.dev{grid-template-columns:1fr;gap:28px}
  .layers li{grid-template-columns:1fr}
  .road{grid-template-columns:1fr 1fr}
  .fgrid{grid-template-columns:1fr 1fr}
  .legal-wrap{grid-template-columns:1fr;gap:16px}
  .toc{position:static;flex-direction:row;flex-wrap:wrap;gap:4px 14px}
  .toc strong{width:100%}
}
@media (max-width:760px){
  .app{grid-template-columns:1fr}
  .side{flex-direction:row;overflow-x:auto;border-right:0;border-bottom:1px solid var(--border);padding:8px}
  .streak{display:none}
  .pane{padding:16px}
  .pairs,.safe{grid-template-columns:1fr}
  .rate{grid-template-columns:1fr}
}
@media (max-width:560px){
  .wrap{padding:0 16px}
  .bar{gap:8px}
  .tools{gap:6px}
  .brand{gap:8px;font-size:.98rem}
  .lang button{padding:0 8px}
  .btn.sm{padding:0 11px}
  #open-pal{display:none}
  .hero{padding-top:44px}
  .sec{padding-top:64px}
  .road,.fgrid{grid-template-columns:1fr}
  .phones{gap:12px}
  .pm{font-size:.62rem}
  .seg button{padding:7px 10px}
  .bar-row{grid-template-columns:72px 1fr 36px}
  .bars.levels .bar-row{grid-template-columns:72px 1fr 88px}
  .bars.levels .bar-row b{white-space:normal;font-size:.78rem;line-height:1.25}
  .actions .btn{flex:1 1 100%}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none!important;animation:none!important}
}
.pairs dt{font-weight:600}

/* ---------- mobile: iOS and Android ---------- */
html{-webkit-tap-highlight-color:transparent}
button,a,.seg,.tab{touch-action:manipulation}
body{overscroll-behavior-y:none}
.site-head{padding-top:env(safe-area-inset-top)}
.wrap{padding-left:max(20px,env(safe-area-inset-left));padding-right:max(20px,env(safe-area-inset-right))}
.menu-btn{display:none;width:40px;justify-content:center;padding:0}
.dock{display:none}
.drawer{position:fixed;inset:0;z-index:40}
.scrim{position:absolute;inset:0;background:rgba(10,12,8,.5);opacity:0;transition:opacity .25s}
.sheet{position:absolute;top:0;right:0;bottom:0;width:min(320px,86vw);display:flex;flex-direction:column;background:var(--background);border-left:1px solid var(--border);padding:max(16px,env(safe-area-inset-top)) 20px max(20px,env(safe-area-inset-bottom));transform:translateX(100%);transition:transform .3s var(--ease);overflow-y:auto}
.drawer.open .scrim{opacity:1}
.drawer.open .sheet{transform:none}
.sheet-h{display:flex;align-items:center;justify-content:space-between;font-weight:700;margin-bottom:8px}
.sheet a:not(.btn){display:flex;align-items:center;min-height:48px;border-bottom:1px solid var(--border);text-decoration:none;font-size:1rem}
.sheet-f{margin-top:auto;padding-top:20px}
.sheet-f .btn{width:100%}
@media (max-width:760px){
  body{padding-bottom:calc(76px + env(safe-area-inset-bottom))}
  .dock{position:fixed;left:0;right:0;bottom:0;z-index:30;padding:10px max(16px,env(safe-area-inset-right)) calc(10px + env(safe-area-inset-bottom)) max(16px,env(safe-area-inset-left));background:var(--background);border-top:1px solid var(--border)}
  .dock{display:grid;grid-template-columns:1fr 1.6fr;gap:10px}
  .dock .btn{width:100%;min-height:48px}
  .toast{bottom:calc(84px + env(safe-area-inset-bottom))}
  .btn.sm.try{display:none}
  .tab{min-height:44px}
  .seg button{min-height:40px}
  .lang button{height:38px}
  .ghost-btn{height:40px}
  .q{min-height:52px}
  .act{min-height:34px;display:inline-flex;align-items:center}
  .site-foot{margin-top:64px}
  #pal-opts button{width:28px;height:28px}
}
@media (max-width:480px){.tools .lang,.tools #theme{display:none}}
.cbox input{font-size:16px}
.addr{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.link{display:inline-flex;align-items:center;min-height:36px}
@media (max-width:380px){.bar{gap:6px}.brand{font-size:.92rem;gap:6px}.brand svg{width:22px;height:22px}.lang button{padding:0 7px}.menu-btn,.ghost-btn{width:36px;padding:0;justify-content:center}}
@media (max-width:420px){#phap-ly .seg{display:flex;width:100%}#phap-ly .seg button{flex:1;white-space:normal;padding:7px 6px;line-height:1.25}}

.nav a[aria-current]{color:var(--foreground);font-weight:600}
.pg-in{animation:pgin .28s var(--ease)}
@keyframes pgin{from{opacity:0;transform:translateY(6px)}}
.sec.lead-sec{padding-top:48px}
.go-list{display:block}
.go{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,2fr);gap:4px 32px;align-items:baseline;padding:18px 0;border-bottom:1px solid var(--border);text-decoration:none}
.go p{color:var(--muted-foreground)}
.go h3::after{content:"";display:inline-block;width:.5em;height:.5em;margin-left:.6em;border:solid var(--muted-foreground);border-width:2px 2px 0 0;transform:rotate(45deg);transition:transform .2s var(--ease),border-color .2s}
.go:hover h3::after{transform:translateX(4px) rotate(45deg);border-color:var(--primary)}
.go:hover h3{color:var(--primary)}
.sheet-row{display:flex;gap:8px;margin-bottom:12px}
.to-top{position:fixed;right:max(16px,env(safe-area-inset-right));bottom:max(20px,env(safe-area-inset-bottom));z-index:25;display:grid;place-items:center;width:44px;height:44px;border-radius:50%;border:1px solid var(--border);background:var(--card);color:var(--foreground);box-shadow:0 4px 14px rgba(0,0,0,.12);opacity:0;transform:translateY(10px);pointer-events:none;transition:opacity .2s,transform .25s var(--ease),background-color .15s}
.to-top.show{opacity:1;transform:none;pointer-events:auto}
.to-top:hover{background:var(--card-2)}
@media (max-width:760px){.to-top{bottom:calc(88px + env(safe-area-inset-bottom))}.go{grid-template-columns:1fr}}
@media (max-width:1100px){.menu-btn{display:inline-flex}}

#safety-root h2+.sub{margin-top:10px}
#safety-root .sub+.safe{margin-top:28px}

/* ---------- motion ---------- */
.site-head{transition:background-color .3s,box-shadow .3s,border-color .3s}
.site-head.scrolled{background:color-mix(in srgb,var(--background) 80%,transparent);-webkit-backdrop-filter:saturate(1.5) blur(12px);backdrop-filter:saturate(1.5) blur(12px);box-shadow:0 8px 24px -18px rgba(0,0,0,.45)}
.read-bar{position:absolute;left:0;right:0;bottom:-1px;height:2px;background:var(--primary);transform:scaleX(0);transform-origin:left;pointer-events:none}
.mo .rv{opacity:0;transform:translate3d(0,22px,0);transition:opacity .7s var(--ease),transform .8s var(--ease);transition-delay:var(--rd,0ms)}
.mo .feat > .rv:nth-child(2){transform:translate3d(18px,22px,0)}
.mo .rv.rv-in{opacity:1;transform:none}
.hero h1{transition:letter-spacing .9s var(--ease)}
.mo .hero h1.rv{letter-spacing:.01em}
.mo .hero h1.rv-in{letter-spacing:-.012em}
.btn{transition:background-color .15s,border-color .15s,transform .2s var(--ease),box-shadow .25s var(--ease)}
.btn:active{transform:scale(.97)}
.fcard,.demo,.win{transition:transform .3s var(--ease),box-shadow .3s var(--ease),border-color .3s}
@media (hover:hover){
  .btn:hover{transform:translateY(-2px);box-shadow:0 10px 22px -14px color-mix(in srgb,var(--primary) 70%,transparent)}
  .btn.plain:hover{box-shadow:0 10px 22px -16px rgba(0,0,0,.35)}
  .fcard:hover,.demo:hover{transform:translateY(-4px);border-color:color-mix(in srgb,var(--primary) 45%,var(--border));box-shadow:0 18px 36px -24px rgba(0,0,0,.35)}
  .win:hover{box-shadow:0 22px 44px -28px rgba(0,0,0,.4)}
  .nav a{background:linear-gradient(currentColor,currentColor) 0 100%/0 1px no-repeat;transition:background-size .3s var(--ease),color .2s}
  .nav a:hover{background-size:100% 1px}
}
@media (prefers-reduced-motion:reduce){.read-bar{display:none}}

/* ---------- phone mockups: realistic devices ----------
   Metal rim (.device) with side buttons, black bezel and glass glare (.phone), real status bar,
   app header, chat with timestamps, composer and tab bar. The frame is always dark metal, like a
   real phone, so it stands out in light and dark themes alike. */
.device{position:relative;padding:3px;border-radius:44px;background:linear-gradient(145deg,#6a6e66 0%,#2c2e2a 20%,#1a1b18 50%,#30332e 80%,#72766e 100%);box-shadow:0 0 0 1px rgba(0,0,0,.55),inset 0 0 0 1px rgba(255,255,255,.16),0 34px 60px -30px rgba(0,0,0,.6),0 12px 24px -16px rgba(0,0,0,.4)}
.device.and{border-radius:34px}
.dbtn{position:absolute;width:3px;border-radius:2px;background:linear-gradient(90deg,#1b1c1a,#767a72 55%,#2a2c28)}
.device .act-b{left:-2px;top:86px;height:22px}
.device .vol-u{left:-2px;top:122px;height:40px}
.device .vol-d{left:-2px;top:170px;height:40px}
.device .pwr{right:-2px;top:140px;height:64px}
.device.and .vol-u{left:auto;right:-2px;top:104px;height:58px}
.device.and .vol-d{display:none}
.device.and .pwr{top:180px;height:34px}
.phone{position:relative;width:208px;height:430px;border:7px solid #0a0b09;border-radius:41px;background:var(--background);overflow:hidden;display:flex;flex-direction:column;isolation:isolate}
.phone.and{border-width:6px;border-radius:31px}
.phone::after{content:"";position:absolute;inset:0;border-radius:inherit;pointer-events:none;z-index:5;background:linear-gradient(115deg,rgba(255,255,255,.16) 0%,rgba(255,255,255,.04) 26%,transparent 40%)}
.isl{position:absolute;top:7px;left:50%;width:64px;height:19px;margin-left:-32px;border-radius:99px;background:#000;z-index:6}
.hole{position:absolute;top:8px;left:50%;width:11px;height:11px;margin-left:-5.5px;border-radius:50%;background:#000;box-shadow:inset 0 0 0 2px #1d1e1b;z-index:6}
.sb{display:flex;justify-content:space-between;align-items:center;flex:none;height:32px;padding:0 18px 0 26px;font-size:.66rem;font-weight:600}
.phone.and .sb{height:27px;padding:0 14px;font-size:.62rem}
.sb-ic{display:flex;align-items:center;gap:4px}
.sb-ic svg{height:8px;width:auto;fill:currentColor}
.bat{position:relative;width:18px;height:9px;padding:1px;border:1px solid currentColor;border-radius:3px}
.bat::after{content:"";position:absolute;right:-3px;top:2.5px;width:1.5px;height:3px;border-radius:0 1px 1px 0;background:currentColor}
.bat i{display:block;width:78%;height:100%;border-radius:1.5px;background:currentColor}
.ahead{display:flex;align-items:center;gap:7px;flex:none;padding:5px 12px 8px;border-bottom:1px solid var(--border)}
.aback{width:14px;height:14px;flex:none;fill:none;stroke:var(--primary);stroke-width:2.4;stroke-linecap:round;stroke-linejoin:round}
.aav{display:grid;place-items:center;width:24px;height:24px;flex:none;border-radius:50%;background:var(--primary)}
.aav svg{width:11px;height:11px;fill:var(--primary-foreground)}
.atit{display:flex;flex-direction:column;min-width:0;line-height:1.2}
.atit b{font-size:.74rem}
.atit small{display:flex;align-items:center;gap:4px;font-size:.58rem;color:var(--muted-foreground)}
.atit .dot{width:5px;height:5px;border-radius:50%;background:#34c759;animation:ping 2.2s infinite}
@keyframes ping{0%{box-shadow:0 0 0 0 rgba(52,199,89,.55)}80%,100%{box-shadow:0 0 0 5px rgba(52,199,89,0)}}
.pc{flex:1;min-height:0;overflow:hidden;display:flex;flex-direction:column;justify-content:flex-end;gap:6px;padding:8px 10px;-webkit-mask-image:linear-gradient(to bottom,transparent 0,#000 22px);mask-image:linear-gradient(to bottom,transparent 0,#000 22px)}
.pday{align-self:center;margin-bottom:2px;padding:2px 8px;border-radius:99px;background:var(--card-2);font-size:.55rem;color:var(--muted-foreground)}
.pm{display:flex;flex-direction:column;gap:2px;max-width:84%;padding:6px 9px 4px;border-radius:14px;font-size:.66rem;line-height:1.38;transition:opacity .35s var(--ease),transform .4s var(--ease)}
.pm time{align-self:flex-end;font-size:.5rem;opacity:.65}
.pm.me{align-self:flex-end;background:var(--primary);color:var(--primary-foreground);border-bottom-right-radius:4px;transform-origin:right bottom}
.pm.ai{align-self:flex-start;background:var(--card-2);border-bottom-left-radius:4px;transform-origin:left bottom}
.pm.wait{opacity:0;transform:translateY(10px) scale(.94)}
.ptype{display:none;align-self:flex-start;gap:3px;padding:8px 10px;border-radius:14px 14px 14px 4px;background:var(--card-2)}
.ptype.on{display:flex}
.ptype i{width:5px;height:5px;border-radius:50%;background:var(--muted-foreground);animation:blink 1s infinite}
.ptype i:nth-child(2){animation-delay:.15s}.ptype i:nth-child(3){animation-delay:.3s}
.pcomp{display:flex;align-items:center;gap:6px;flex:none;margin:4px 8px 6px;padding:4px 4px 4px 6px;border:1px solid var(--border);border-radius:99px;background:var(--card)}
.pplus{display:grid;place-items:center;width:18px;height:18px;border-radius:50%;background:var(--card-2);font-size:.75rem;line-height:1;color:var(--muted-foreground)}
.pin{flex:1;overflow:hidden;white-space:nowrap;text-overflow:ellipsis;font-size:.62rem;color:var(--muted-foreground)}
.psend{display:grid;place-items:center;width:22px;height:22px;border-radius:50%;background:var(--primary);color:var(--primary-foreground)}
.psend svg{width:11px;height:11px}
.pnav{display:flex;justify-content:space-around;flex:none;padding:6px 4px 2px;border-top:1px solid var(--border);background:var(--card)}
.pnav span{display:flex;flex-direction:column;align-items:center;gap:2px;color:var(--muted-foreground)}
.pnav svg{width:16px;height:16px}
.pnav em{font-style:normal;font-size:.5rem}
.pnav .on{color:var(--primary)}
.hbar{flex:none;width:74px;height:4px;margin:4px auto 6px;border-radius:9px;background:var(--foreground);opacity:.85}
.phone.and .hbar{width:54px;height:3px;opacity:.45}
.pw.cur .device{animation:dfloat 6s ease-in-out infinite}
@keyframes dfloat{50%{transform:translateY(-7px)}}
@media (max-width:620px){.device{zoom:.74}}