/* The X Algorithm: X's own light look. White ground, black type, grey hairlines, one blue, black pill buttons. */
:root{
  --bg:#fff;--bg2:#f7f9f9;--bg3:#eff3f4;--line:#eff3f4;--line2:#cfd9de;
  --text:#0f1419;--text2:#3c4348;--muted:#536471;
  --blue:#1d9bf0;--blue2:#1a8cd8;--blue-dim:rgba(29,155,240,.14);
  --green:#00ba7c;--red:#f4212e;--amber:#ffd400;
  --sans:Inter,-apple-system,"Segoe UI",Helvetica,Arial,sans-serif;
  --serif:Literata,Georgia,"Times New Roman",serif;
  --r:16px;--card:#fff;--stage:#0f1419;--stage-text:#fff;--btn:#0f1419;--btn-text:#fff;--btn-hover:#272c30;
  color-scheme:light;
}
/* dark: X's "lights out". Black ground, dark greys for surfaces and lines, white type, the same blue. */
:root[data-theme="dark"]{
  --bg:#000;--bg2:#0b0e11;--bg3:#16181c;--line:#2f3336;--line2:#3e4144;
  --text:#e7e9ea;--text2:#b9bfc4;--muted:#71767b;
  --card:#0b0e11;--stage:#16181c;--stage-text:#fff;--btn:#fff;--btn-text:#0f1419;--btn-hover:#d7dbdc;
  color-scheme:dark;
}
*{box-sizing:border-box}
html{font-size:16px;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font-family:var(--sans);line-height:1.5;-webkit-font-smoothing:antialiased}
a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}
img{max-width:100%;display:block}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
.narrow{max-width:720px;margin:0 auto;padding:0 20px}
h1,h2,h3{margin:0;font-weight:800;letter-spacing:-.02em;line-height:1.1;text-wrap:balance}
h1{font-size:clamp(2.2rem,5.2vw,4rem)}
h2{font-size:clamp(1.6rem,3vw,2.4rem)}
h3{font-size:1.15rem;letter-spacing:-.01em}
p{margin:0 0 1em}
.muted{color:var(--muted)}
.eyebrow{display:block;font-size:.78rem;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--blue);margin:0 0 14px}
.lede{font-size:1.15rem;color:var(--text2);line-height:1.6;max-width:62ch}
.tab{font-variant-numeric:tabular-nums}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:0 22px;border-radius:999px;font-weight:700;font-size:1rem;border:1px solid transparent;cursor:pointer;font-family:inherit;line-height:1;white-space:nowrap;transition:background .15s,border-color .15s}
.btn:hover{text-decoration:none}
.btn-blue{background:var(--btn);color:var(--btn-text)}.btn-blue:hover{background:var(--btn-hover)}
.btn-white{background:var(--blue);color:#fff}.btn-white:hover{background:var(--blue2)}
.btn-line{background:transparent;color:var(--text);border-color:var(--line2)}.btn-line:hover{background:var(--bg3)}
.btn-sm{min-height:36px;padding:0 14px;font-size:.9rem}
.btn[disabled]{opacity:.5;cursor:not-allowed}

/* top bar */
.top{position:sticky;top:0;z-index:20;background:color-mix(in srgb,var(--bg) 85%,transparent);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.top .wrap{display:flex;align-items:center;justify-content:space-between;height:60px;gap:16px}
.brand{display:flex;align-items:center;gap:10px;color:var(--text);font-weight:800;letter-spacing:-.02em;font-size:1.05rem}
.brand:hover{text-decoration:none}
.brand .x{display:inline-grid;place-items:center;width:30px;height:30px;border-radius:8px;background:var(--btn);color:var(--btn-text);font-weight:900;font-size:1rem;letter-spacing:0}
.nav{display:flex;align-items:center;gap:18px;font-size:.95rem}
.nav a{color:var(--text2)}.nav a:hover{color:var(--text);text-decoration:none}
@media (max-width:640px){.nav .hide-m{display:none}}

/* flash */
.flash{max-width:1080px;margin:14px auto 0;padding:0 20px}
.flash div{padding:12px 16px;border-radius:12px;border:1px solid var(--line2);background:var(--card);font-size:.95rem}
.flash .ok{border-color:rgba(0,186,124,.4)}.flash .warn{border-color:rgba(244,33,46,.5)}.flash .info{border-color:rgba(29,155,240,.4)}

/* hero */
.hero{padding:72px 0 56px;border-bottom:1px solid var(--line)}
.hero .wrap{display:grid;grid-template-columns:1.25fr .75fr;gap:56px;align-items:center}
@media (max-width:860px){.hero .wrap{grid-template-columns:1fr}.hero{padding:44px 0 40px}}
.hero .lede{margin:22px 0 28px}
.cta{display:flex;flex-wrap:wrap;gap:12px;align-items:center}
.cta .note{width:100%;color:var(--muted);font-size:.9rem;margin-top:6px}

/* the cover, drawn in CSS: a dark book with a white title block */
.cover{aspect-ratio:6/9;width:min(100%,340px);margin:0 auto;border-radius:6px 14px 14px 6px;background:linear-gradient(135deg,#1b1f23,#050607 60%);border:1px solid var(--line2);box-shadow:0 30px 80px rgba(0,0,0,.7),inset 6px 0 14px rgba(255,255,255,.04);padding:34px 30px;display:flex;flex-direction:column;justify-content:space-between;position:relative;overflow:hidden}
.cover::after{content:"";position:absolute;inset:0;background:radial-gradient(ellipse at 20% 0%,rgba(29,155,240,.25),transparent 55%);pointer-events:none}
.cover .ce{font-size:.66rem;letter-spacing:.2em;text-transform:uppercase;color:var(--blue);font-weight:700}
.cover .ct{font-size:2.1rem;font-weight:900;letter-spacing:-.03em;line-height:.98;color:#fff;margin:14px 0 12px}
.cover .cs{font-size:.86rem;color:#b9bfc4;line-height:1.35}
.cover .ca{font-size:.8rem;color:#fff;font-weight:700}
.cover .cu{font-size:.62rem;letter-spacing:.16em;text-transform:uppercase;color:var(--blue);font-weight:700;margin-top:6px}

/* number band */
.nums{display:grid;grid-template-columns:repeat(4,1fr);border-bottom:1px solid var(--line)}
.nums div{padding:28px 20px;border-right:1px solid var(--line)}
.nums div:last-child{border-right:0}
.nums b{display:block;font-size:2.4rem;font-weight:800;letter-spacing:-.03em;line-height:1;color:var(--text);margin-bottom:8px;font-variant-numeric:tabular-nums}
.nums span{color:var(--muted);font-size:.9rem;line-height:1.4}
@media (max-width:860px){.nums{grid-template-columns:1fr 1fr}.nums div:nth-child(2n){border-right:0}.nums div{border-bottom:1px solid var(--line)}}

/* sections */
.sec{padding:64px 0;border-bottom:1px solid var(--line)}
.sec-h{max-width:62ch;margin-bottom:34px}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media (max-width:860px){.grid3,.grid2{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line2);border-radius:var(--r);padding:24px}
.card h3{margin-bottom:8px}
.card p{color:var(--text2);margin:0}
.card p+p{margin-top:.8em}

/* the points table */
.points{border:1px solid var(--line2);border-radius:var(--r);overflow:hidden;background:var(--card)}
.points .row{display:flex;justify-content:space-between;align-items:center;padding:12px 18px;border-top:1px solid var(--line);font-size:.98rem}
.points .row:first-child{border-top:0;color:var(--muted);font-size:.78rem;letter-spacing:.12em;text-transform:uppercase;font-weight:700}
.points b{font-variant-numeric:tabular-nums;font-size:1.1rem;color:var(--text)}
.points .neg b{color:var(--red)}
.points .foot{padding:10px 18px;color:var(--muted);font-size:.85rem;border-top:1px solid var(--line)}

/* preview */
.peek{padding:64px 0;border-bottom:1px solid var(--line);background:var(--bg2)}
.peek .frame{position:relative;max-height:520px;overflow:hidden;border:1px solid var(--line2);border-radius:var(--r);background:#fffdf8;color:#1a1714;padding:40px 44px;font-family:var(--serif);font-size:1.05rem;line-height:1.65;-webkit-mask-image:linear-gradient(180deg,#000 55%,transparent);mask-image:linear-gradient(180deg,#000 55%,transparent)}
.peek .frame h3{font-family:var(--serif);font-weight:600;color:#9b2f2c;font-size:1.05rem;margin:18px 0 6px}
.peek .frame p{margin:0 0 .9em}
.peek .frame ul{margin:0 0 1em 1.2em;padding:0}
.peek table{border-collapse:collapse;width:100%;font-family:var(--sans);font-size:.82rem;margin:8px 0 16px}
.peek th,.peek td{text-align:left;padding:5px 8px;border-bottom:1px solid rgba(26,23,20,.12);vertical-align:top}
.peek th{font-size:.7rem;letter-spacing:.1em;text-transform:uppercase;color:#746963}
.peek .n{text-align:right;white-space:nowrap;font-variant-numeric:tabular-nums}
.peek .go{text-align:center;margin-top:-30px;position:relative;z-index:2}

/* changes */
.log{border:1px solid var(--line2);border-radius:var(--r);overflow:hidden}
.log .ent{padding:20px 22px;border-top:1px solid var(--line);display:grid;grid-template-columns:150px 1fr;gap:18px}
.log .ent:first-child{border-top:0}
.log .d{color:var(--blue);font-weight:700;font-size:.85rem;letter-spacing:.08em;text-transform:uppercase}
.log ul{margin:0;padding-left:18px;color:var(--text2)}
.log li{margin:0 0 4px}
@media (max-width:640px){.log .ent{grid-template-columns:1fr;gap:6px}}

/* faq */
.faq{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media (max-width:860px){.faq{grid-template-columns:1fr}}

/* where */
.where .card{display:flex;flex-direction:column;gap:14px}
.where ul{margin:0;padding-left:18px;color:var(--text2);flex:1}
.where li{margin:0 0 6px}
.fine{color:var(--muted);font-size:.85rem;line-height:1.5;max-width:70ch;margin-top:24px}

/* forms */
.field{margin:0 0 16px}
.field label{display:block;font-size:.85rem;color:var(--muted);margin-bottom:6px}
input[type=text],input[type=email],input[type=url],input[type=number],input[type=password],textarea,select{width:100%;background:var(--bg);color:var(--text);border:1px solid var(--line2);border-radius:10px;padding:12px 14px;font:inherit;font-size:1rem}
input:focus,textarea:focus,select:focus{outline:none;border-color:var(--blue)}
textarea{min-height:120px;resize:vertical}
.help{color:var(--muted);font-size:.85rem;margin-top:6px}

/* sign-in card */
.auth{max-width:440px;margin:80px auto;padding:0 20px}
.auth .card{padding:32px}
.auth h1{font-size:1.8rem;margin-bottom:8px}

/* library */
.lib{padding:56px 0}
.lib .stat{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:26px 0}
@media (max-width:700px){.lib .stat{grid-template-columns:1fr}}
.lib .stat div{padding:18px 20px;border:1px solid var(--line2);border-radius:var(--r);background:var(--card)}
.lib .stat small{display:block;color:var(--muted);font-size:.78rem;letter-spacing:.1em;text-transform:uppercase;font-weight:700;margin-bottom:6px}
.lib .stat b{font-size:1.3rem;font-weight:800;letter-spacing:-.02em}
.renew{border:1px solid rgba(29,155,240,.5);background:var(--blue-dim);border-radius:var(--r);padding:22px 24px;display:flex;flex-wrap:wrap;gap:16px;align-items:center;justify-content:space-between;margin:22px 0}
.renew p{margin:0;max-width:60ch}
table.list{width:100%;border-collapse:collapse;font-size:.95rem}
table.list th{text-align:left;color:var(--muted);font-size:.75rem;letter-spacing:.1em;text-transform:uppercase;padding:10px 12px;border-bottom:1px solid var(--line)}
table.list td{padding:12px;border-bottom:1px solid var(--line);vertical-align:top}

/* footer */
.foot{padding:40px 0 60px;color:var(--muted);font-size:.88rem}
.foot .wrap{display:flex;flex-wrap:wrap;gap:16px 28px;justify-content:space-between;align-items:center}
.foot a{color:var(--text2)}

/* reader chrome */
.rd{position:fixed;inset:0;display:grid;grid-template-rows:52px 1fr;background:var(--bg3)}
.rd .bar{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:0 16px;border-bottom:1px solid var(--line2);background:var(--bg)}
.rd .bar .l,.rd .bar .r{display:flex;align-items:center;gap:14px;font-size:.9rem}
.rd .bar b{font-weight:800;letter-spacing:-.01em}
.rd iframe{width:100%;height:100%;border:0;background:#f3efe7}
.rd .pg{color:var(--muted);font-variant-numeric:tabular-nums}
@media (max-width:640px){.rd .bar .hide-m{display:none}}

/* terms page */
.terms{padding:56px 0}
.terms h1{margin-bottom:6px}
.terms h2{font-size:1.2rem;margin:30px 0 8px}
.terms p{color:var(--text2);max-width:72ch}

/* the one black band, like X's Post button */
.stage{background:var(--stage);color:var(--stage-text);border-bottom:0}
.stage h2{color:var(--stage-text)}.stage .lede{color:#b9bfc4}.stage .eyebrow{color:var(--blue)}
.stage .btn-blue{background:#fff;color:#0f1419}.stage .btn-blue:hover{background:#e7e9ea}
.stage .btn-line{color:#fff;border-color:#3e4144}.stage .btn-line:hover{background:#272c30}

/* sun / moon */
.theme{display:inline-grid;place-items:center;width:36px;height:36px;border-radius:999px;border:1px solid var(--line2);background:transparent;color:var(--text);cursor:pointer;padding:0}
.theme:hover{background:var(--bg3)}
.theme svg{width:18px;height:18px}
.theme .moon{display:none}
:root[data-theme="dark"] .theme .sun{display:none}
:root[data-theme="dark"] .theme .moon{display:block}
input[type=text],input[type=email],input[type=url],input[type=number],input[type=password],textarea,select{background:var(--card)}

/* the preview: one reading column on the book's paper, the site's bar above it */
.pv-bar{position:sticky;top:0;z-index:5;display:flex;align-items:center;justify-content:space-between;gap:14px;height:60px;padding:0 20px;background:color-mix(in srgb,var(--bg) 85%,transparent);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.pv-bar .r{display:flex;align-items:center;gap:14px}
.pv-page{max-width:680px;margin:40px auto 80px;padding:0 20px}
.pv-page h1{font-family:var(--serif);font-weight:600;letter-spacing:-.01em;font-size:clamp(1.8rem,4vw,2.6rem);margin:0 0 22px}
.pv-text{font-family:var(--serif);font-size:1.2rem;line-height:1.65;color:var(--text)}
.pv-text h3{font-family:var(--serif);font-weight:600;font-size:1.2rem;margin:26px 0 8px}
.pv-text p{margin:0 0 1em}
.pv-text ul{margin:0 0 1em 1.2em;padding:0}
.pv-text li{margin:0 0 .5em}
.pv-text table{border-collapse:collapse;width:100%;font-family:var(--sans);font-size:.88rem;margin:10px 0 20px}
.pv-text th,.pv-text td{text-align:left;padding:7px 9px;border-bottom:1px solid var(--line2);vertical-align:top}
.pv-text th{font-size:.72rem;letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.pv-text .n{text-align:right;white-space:nowrap;font-variant-numeric:tabular-nums}
.pv-text{-webkit-mask-image:linear-gradient(180deg,#000 calc(100% - 220px),transparent);mask-image:linear-gradient(180deg,#000 calc(100% - 220px),transparent)}
.pv-gate{text-align:center;margin-top:-40px;position:relative;padding:28px;border:1px solid var(--line2);border-radius:var(--r);background:var(--card)}
.pv-gate h2{font-size:1.5rem;margin-bottom:8px}
.pv-gate p{color:var(--text2);max-width:48ch;margin:0 auto 18px}

.social{display:flex;flex-direction:column;gap:10px;margin:18px 0 6px}
.social .btn{width:100%;justify-content:center;gap:10px}
.or{display:flex;align-items:center;gap:12px;color:var(--muted);font-size:.82rem;margin:16px 0 10px}
.or::before,.or::after{content:"";flex:1;border-top:1px solid var(--line2)}