/* ===========================================================================
   SymptomsEase AI — "Clinical Editorial" design
   Serif display (Fraunces) + mono labels (JetBrains Mono) + indexed hairline
   grid. Purple->blue accent, restrained. Dark + light, RTL-aware, a11y-tuned.
   =========================================================================== */

:root {
  /* dark (default) */
  --bg: #0e0b15;
  --bg-2: #120e1c;
  --surface: #161221;
  --surface-2: #1d1830;
  --line: #271f38;
  --line-2: #352c4a;
  --text: #efedf7;
  --text-2: #b3acc6;
  --muted: #9890ad;
  --primary: #8b5cf6;
  --primary-press: #7c4cf0;
  --blue: #5b8def;
  --accent-text: #bda9f8;          /* accent-colored TEXT (links, numbers) — AA on dark */
  --on-primary: #ffffff;
  --grad: linear-gradient(118deg, #7c3aed 0%, #3b6fe0 100%); /* both stops clear AA for white text */
  --grad-veil: linear-gradient(118deg, rgba(139,92,246,.14), rgba(91,141,239,.12));
  --shadow: 0 30px 70px -34px rgba(0,0,0,.8);
  --ring: #b69bff;

  --maxw: 1180px;
  --rail: 190px;
  --header-h: 64px;
  --radius: 4px;          /* editorial = low radius, hairlines do the work */
  --radius-lg: 10px;

  --font: "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --mono: "JetBrains Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
  --font-ar: "IBM Plex Sans Arabic", "Tajawal", "Segoe UI", system-ui, sans-serif;
}

[data-theme="light"] {
  --bg: #f3f1fb;
  --bg-2: #ece9f7;
  --surface: #ffffff;
  --surface-2: #f6f4fd;
  --line: #e6e1f4;
  --line-2: #d7d0ec;
  --text: #161222;
  --text-2: #47415d;
  --muted: #615b76;
  --primary: #6d45e0;
  --primary-press: #5a32cc;
  --blue: #2f6fe0;
  --accent-text: #5a33c8;          /* AA on light bg */
  --on-primary: #ffffff;
  --grad: linear-gradient(118deg, #6d45e0 0%, #2456c8 100%);
  --grad-veil: linear-gradient(118deg, rgba(109,69,224,.08), rgba(47,111,224,.08));
  --shadow: 0 26px 60px -34px rgba(60,40,120,.4);
  --ring: #6d45e0;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }
body {
  margin: 0; background: var(--bg); color: var(--text); font-family: var(--font);
  font-size: 17px; line-height: 1.7; -webkit-font-smoothing: antialiased;
  overflow-x: hidden; transition: background .35s, color .35s;
}
[dir="rtl"] body { font-family: var(--font-ar); }
img { max-width: 100%; display: block; }
.container { width: min(100% - 44px, var(--maxw)); margin-inline: auto; }

h1, h2, h3 { margin: 0; font-family: var(--serif); font-weight: 600; line-height: 1.08; letter-spacing: -.015em; }
[dir="rtl"] h1, [dir="rtl"] h2, [dir="rtl"] h3 { font-family: var(--font-ar); font-weight: 700; letter-spacing: 0; line-height: 1.3; }
p { margin: 0 0 1rem; color: var(--text-2); }
a { color: var(--accent-text); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

.mono { font-family: var(--mono); }
[dir="rtl"] .label-text { font-family: var(--font-ar); }

/* focus-visible ring (a11y) */
:focus-visible { outline: 2px solid var(--ring); outline-offset: 3px; border-radius: 4px; }
:focus:not(:focus-visible) { outline: none; }

.skip-link {
  position: fixed; inset-inline-start: 14px; top: -60px; z-index: 300;
  background: var(--primary); color: #fff; padding: 10px 16px; border-radius: 6px; transition: top .2s;
}
.skip-link:focus { top: 14px; }

/* ---------------------------------------------------------------- header */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: color-mix(in srgb, var(--bg) 82%, transparent); backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--line); transition: box-shadow .25s, border-color .25s;
}
.site-header.scrolled { box-shadow: 0 1px 0 var(--line), 0 14px 30px -26px rgba(0,0,0,.6); }
.header-inner { display: flex; align-items: center; gap: 20px; height: var(--header-h); }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; font-size: 1rem; }
.brand img { border-radius: 8px; }
.brand-name { font-family: var(--serif); font-weight: 600; font-size: 1.18rem; letter-spacing: -.01em; }
[dir="rtl"] .brand-name { font-family: var(--font-ar); font-weight: 700; }
.main-nav { display: flex; gap: 2px; margin-inline: auto; flex-wrap: wrap; }
.main-nav a {
  color: var(--text-2); padding: 8px 12px; border-radius: 6px; font-family: var(--mono);
  font-size: .76rem; text-transform: uppercase; letter-spacing: .08em; font-weight: 500; transition: color .2s, background .2s;
}
[dir="rtl"] .main-nav a { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; font-size: .9rem; }
.main-nav a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.header-controls { display: flex; align-items: center; gap: 8px; }
.icon-btn, .lang-btn {
  border: 1px solid var(--line-2); background: var(--surface); color: var(--text); height: 38px;
  border-radius: 6px; cursor: pointer; font: inherit; display: inline-flex; align-items: center; justify-content: center; transition: border-color .2s, color .2s;
}
.icon-btn { width: 38px; font-size: 1rem; }
.lang-btn { padding: 0 13px; font-family: var(--mono); font-size: .76rem; letter-spacing: .04em; }
[dir="rtl"] .lang-btn { font-family: var(--font); }
.icon-btn:hover, .lang-btn:hover { border-color: var(--primary); }
.menu-toggle { display: none; }

/* ---------------------------------------------------------------- buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  padding: 13px 24px; border-radius: 7px; font-weight: 600; font-size: .98rem; font-family: var(--font);
  cursor: pointer; border: 1px solid transparent; transition: transform .15s, box-shadow .2s, background .2s, border-color .2s; text-align: center;
}
[dir="rtl"] .btn { font-family: var(--font-ar); }
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--grad); color: var(--on-primary); text-shadow: 0 1px 2px rgba(0,0,0,.28); box-shadow: 0 14px 30px -14px var(--primary); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 20px 42px -16px var(--primary); text-decoration: none; }
.btn-ghost { background: transparent; color: var(--text); border-color: var(--line-2); }
.btn-ghost:hover { border-color: var(--primary); color: var(--text); text-decoration: none; }
.btn-link { background: none; border: 0; color: var(--accent-text); padding: 13px 6px; font-weight: 600; border-bottom: 1px solid currentColor; border-radius: 0; }
.btn-lg { padding: 16px 30px; font-size: 1.05rem; }

/* ---------------------------------------------------------------- section frame (indexed editorial) */
section { padding: clamp(46px, 6vw, 92px) 0; border-top: 1px solid var(--line); position: relative; }
section.no-rule { border-top: 0; }
.section-grid { display: grid; grid-template-columns: var(--rail) minmax(0, 1fr); gap: clamp(22px, 4vw, 60px); align-items: start; }
.sec-rail { position: sticky; top: calc(var(--header-h) + 26px); }
.sec-rail .num { font-family: var(--mono); font-size: .8rem; color: var(--accent-text); display: block; }
.sec-rail .label { font-family: var(--mono); text-transform: uppercase; letter-spacing: .14em; font-size: .72rem; color: var(--muted); margin-top: 6px; display: block; }
[dir="rtl"] .sec-rail .label { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; font-size: .85rem; }
.sec-main > h2 { font-size: clamp(1.7rem, 1.1rem + 2.4vw, 2.7rem); margin-bottom: .35em; }
.sec-main > .lead { font-size: 1.2rem; color: var(--text-2); max-width: 60ch; margin-bottom: 1.6rem; }
.sec-main p { max-width: 68ch; }
.stack-gap > * + * { margin-top: 26px; }

/* ---------------------------------------------------------------- hero */
.hero { border-top: 0; padding-top: clamp(40px, 6vw, 86px); padding-bottom: clamp(40px, 6vw, 80px); }
.hero-grid { display: grid; grid-template-columns: 1.55fr .9fr; gap: clamp(28px, 5vw, 72px); align-items: center; }
.hero-kicker { font-family: var(--mono); font-size: .8rem; letter-spacing: .14em; text-transform: uppercase; color: var(--accent-text); margin-bottom: 22px; display: flex; align-items: center; gap: 10px; }
[dir="rtl"] .hero-kicker { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; }
.hero-kicker::before { content: ""; width: 34px; height: 1px; background: var(--accent-text); display: inline-block; }
.hero h1 { font-size: clamp(2.6rem, 1.3rem + 6vw, 5.2rem); font-weight: 600; letter-spacing: -.025em; margin-bottom: .25em; }
.hero h1 em { font-style: italic; color: var(--accent-text); }
.hero p { font-size: 1.08rem; max-width: 52ch; }
.hero-cta { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; margin-top: 30px; }
.hero-aside { border-inline-start: 1px solid var(--line); padding-inline-start: clamp(20px, 3vw, 40px); }
[dir="rtl"] .hero-aside { border-inline-start: 0; border-inline-end: 1px solid var(--line); }
.hero-mark { width: 78px; height: 78px; border-radius: 20px; box-shadow: var(--shadow); margin-bottom: 26px; }
.hero-stats { display: grid; gap: 0; }
.hero-stat { padding: 14px 0; border-top: 1px solid var(--line); display: flex; align-items: baseline; gap: 12px; }
.hero-stat:first-child { border-top: 0; }
.hero-stat .v { font-family: var(--serif); font-size: 1.6rem; font-weight: 600; color: var(--text); min-width: 2.6em; }
[dir="rtl"] .hero-stat .v { font-family: var(--mono); }
.hero-stat .k { font-family: var(--mono); font-size: .74rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); }
[dir="rtl"] .hero-stat .k { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; font-size: .9rem; }
.hero-note { margin-top: 22px; font-size: .82rem; color: var(--muted); font-family: var(--mono); }
[dir="rtl"] .hero-note { font-family: var(--font-ar); }

/* ---------------------------------------------------------------- tiles (features / stack / requirements) */
.tiles { display: grid; gap: 0; grid-template-columns: repeat(2, 1fr); border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; }
.tiles.three { grid-template-columns: repeat(3, 1fr); }
.tile { padding: 24px; border-top: 1px solid var(--line); transition: background .2s; }
.tile:first-child { border-top: 0; }
.tile:hover { background: var(--surface-2); }
@media (min-width: 761px) {
  .tiles .tile { border-inline-start: 1px solid var(--line); }
  .tiles:not(.three) .tile:nth-child(2n+1) { border-inline-start: 0; }
  .tiles:not(.three) .tile:nth-child(-n+2) { border-top: 0; }
  .tiles.three .tile:nth-child(3n+1) { border-inline-start: 0; }
  .tiles.three .tile:nth-child(-n+3) { border-top: 0; }
}
.tile .ti { font-family: var(--mono); font-size: .76rem; color: var(--accent-text); display: block; margin-bottom: 12px; }
.tile h3 { font-family: var(--serif); font-size: 1.12rem; margin-bottom: .35em; }
[dir="rtl"] .tile h3 { font-family: var(--font-ar); }
.tile p { margin: 0; color: var(--text-2); font-size: .95rem; }

/* ---------------------------------------------------------------- steps (how) */
.steps { border-top: 1px solid var(--line); }
.step { display: grid; grid-template-columns: 64px 1fr; gap: 20px; padding: 24px 0; border-bottom: 1px solid var(--line); align-items: baseline; }
.step .sn { font-family: var(--mono); font-size: 1.5rem; color: var(--accent-text); font-weight: 500; }
.step h3 { font-family: var(--serif); font-size: 1.25rem; margin-bottom: .25em; }
[dir="rtl"] .step h3 { font-family: var(--font-ar); }
.step p { margin: 0; }

/* ---------------------------------------------------------------- spec list (model / dataset bullets) */
.spec { display: grid; gap: 0; border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; }
.spec li { list-style: none; padding: 15px 20px; border-top: 1px solid var(--line); display: flex; flex-wrap: wrap; gap: 4px 18px; }
.spec li:first-child { border-top: 0; }
.spec b { font-family: var(--mono); font-weight: 600; color: var(--text); font-size: .9rem; min-width: 200px; }
[dir="rtl"] .spec b { font-family: var(--font-ar); }
.spec span { color: var(--text-2); font-size: .95rem; flex: 1; min-width: 220px; }
.spec ul, .spec { margin: 0; padding: 0; }

/* ---------------------------------------------------------------- tables */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius-lg); }
table { width: 100%; border-collapse: collapse; min-width: 540px; }
caption { caption-side: bottom; padding: 12px 18px; color: var(--muted); font-size: .8rem; text-align: start; font-family: var(--mono); }
[dir="rtl"] caption { font-family: var(--font-ar); }
th, td { padding: 13px 18px; text-align: start; border-top: 1px solid var(--line); font-size: .92rem; }
thead th { border-top: 0; background: var(--surface-2); color: var(--text); font-family: var(--mono); font-weight: 600; font-size: .74rem; text-transform: uppercase; letter-spacing: .06em; }
[dir="rtl"] thead th { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; font-size: .85rem; }
td:not(:nth-child(2)) { font-family: var(--mono); color: var(--text-2); }
tbody tr:hover td { background: var(--surface-2); }

/* ---------------------------------------------------------------- model architecture */
.arch { display: flex; align-items: stretch; gap: 8px; flex-wrap: wrap; padding: 8px 0 4px; }
.layer { min-width: 80px; padding: 14px 12px; border: 1px solid var(--line-2); border-radius: 8px; text-align: center; background: var(--surface); }
.layer .lname { font-family: var(--mono); font-size: .7rem; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; }
[dir="rtl"] .layer .lname { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; }
.layer .lval { font-family: var(--serif); font-weight: 600; font-size: 1.25rem; margin-top: 4px; }
.layer.io { background: var(--grad); color: #fff; border: 0; }
.layer.io .lname { color: #fff; }
.layer.io .lval { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,.28); }
.arch .arrow { align-self: center; color: var(--line-2); font-family: var(--mono); }
[dir="rtl"] .arch .arrow { transform: scaleX(-1); }

/* ---------------------------------------------------------------- results metric */
.metric { display: flex; align-items: flex-end; gap: 18px; padding-bottom: 8px; border-bottom: 1px solid var(--line); margin-bottom: 26px; }
.metric .big { font-family: var(--serif); font-weight: 600; font-size: clamp(3.4rem, 2rem + 6vw, 6rem); line-height: .9; letter-spacing: -.03em; color: var(--primary); }
@supports ((-webkit-background-clip: text) or (background-clip: text)) {
  .metric .big { background: var(--grad); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; color: transparent; }
}
@media (forced-colors: active) { .metric .big { background: none; -webkit-text-fill-color: CanvasText; color: CanvasText; } }
.metric .lbl { font-family: var(--mono); font-size: .8rem; text-transform: uppercase; letter-spacing: .1em; color: var(--muted); padding-bottom: 12px; }
[dir="rtl"] .metric .big { font-family: var(--mono); }
[dir="rtl"] .metric .lbl { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; }

/* ---------------------------------------------------------------- screenshots */
.gallery { display: grid; gap: 20px; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.shot { border: 1px solid var(--line); border-radius: var(--radius-lg); overflow: hidden; background: var(--surface); }
.shot-trigger { display: block; width: 100%; padding: 0; border: 0; background: #0e0b15; cursor: zoom-in; }
.shot-trigger img { width: 100%; height: auto; display: block; transition: opacity .2s; }
.shot-trigger:hover img { opacity: .9; }
.shot figcaption { padding: 14px 18px; border-top: 1px solid var(--line); }
.shot figcaption b { font-family: var(--serif); font-weight: 600; display: block; font-size: 1rem; }
[dir="rtl"] .shot figcaption b { font-family: var(--font-ar); }
.shot figcaption span { color: var(--muted); font-size: .88rem; }

.lightbox { position: fixed; inset: 0; z-index: 400; background: rgba(8,6,16,.92); display: none; align-items: center; justify-content: center; padding: 30px; }
.lightbox.open { display: flex; }
.lightbox img { max-width: 96vw; max-height: 90vh; border-radius: 8px; box-shadow: var(--shadow); }
.lightbox .lb-close { position: fixed; top: 18px; inset-inline-end: 22px; width: 44px; height: 44px; border-radius: 8px; border: 1px solid var(--line-2); background: var(--surface); color: var(--text); font-size: 1.3rem; cursor: pointer; }

/* ---------------------------------------------------------------- faq */
.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 20px 0; font-family: var(--serif); font-weight: 600; font-size: 1.12rem; color: var(--text); list-style: none; display: flex; justify-content: space-between; gap: 18px; align-items: center; }
[dir="rtl"] .faq summary { font-family: var(--font-ar); }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font-family: var(--mono); color: var(--accent-text); font-size: 1.5rem; line-height: 1; }
.faq details[open] summary::after { content: "\2212"; }
.faq details p { margin: 0 0 20px; max-width: 72ch; }

/* ---------------------------------------------------------------- disclaimer */
.disclaimer { background: var(--grad-veil); border: 1px solid var(--line-2); border-radius: var(--radius-lg); padding: 28px 30px; }
.disclaimer .dlabel { font-family: var(--mono); font-size: .74rem; letter-spacing: .14em; text-transform: uppercase; color: var(--accent-text); }
[dir="rtl"] .disclaimer .dlabel { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; }
.disclaimer h2 { font-size: 1.5rem; margin: 8px 0 .4em; }
.disclaimer p { margin: 0; color: var(--text); max-width: 80ch; }

/* ---------------------------------------------------------------- download band */
.download { background: var(--bg-2); }
.download .sec-main > h2 { font-size: clamp(2rem, 1.3rem + 3vw, 3.1rem); }
.download-meta { margin-top: 4px; font-family: var(--mono); font-size: .8rem; color: var(--muted); line-height: 1.9; }
[dir="rtl"] .download-meta { font-family: var(--font-ar); }
.btn-arrow { font-family: var(--mono); }

/* ---------------------------------------------------------------- footer */
.site-footer { border-top: 1px solid var(--line); padding: 46px 0 34px; }
.footer-inner { display: flex; justify-content: space-between; gap: 26px; flex-wrap: wrap; align-items: flex-start; }
.footer-brand { display: flex; align-items: center; gap: 10px; font-family: var(--serif); font-weight: 600; font-size: 1.15rem; }
[dir="rtl"] .footer-brand { font-family: var(--font-ar); }
.footer-brand img { width: 30px; height: 30px; border-radius: 7px; }
.footer-links { display: flex; gap: 8px 20px; flex-wrap: wrap; }
.footer-links a { color: var(--text-2); font-family: var(--mono); font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; }
[dir="rtl"] .footer-links a { font-family: var(--font-ar); text-transform: none; letter-spacing: 0; font-size: .92rem; }
.footer-links a:hover { color: var(--primary); }
.footer-meta { width: 100%; color: var(--muted); font-size: .82rem; border-top: 1px solid var(--line); padding-top: 20px; margin-top: 24px; }

/* ---------------------------------------------------------------- to-top */
.to-top { position: fixed; inset-inline-end: 22px; bottom: 22px; width: 44px; height: 44px; border-radius: 8px; border: 1px solid var(--line-2); background: var(--surface); color: var(--text); font-size: 1.15rem; cursor: pointer; opacity: 0; pointer-events: none; transition: opacity .25s, transform .2s; z-index: 90; }
.to-top.show { opacity: 1; pointer-events: auto; }
.to-top:hover { border-color: var(--primary); transform: translateY(-2px); }

/* ---------------------------------------------------------------- reveal */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s ease, transform .6s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ---------------------------------------------------------------- responsive */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; }
  .hero-aside { border-inline-start: 0; padding-inline-start: 0; border-top: 1px solid var(--line); padding-top: 26px; }
  [dir="rtl"] .hero-aside { border-inline-end: 0; }
  .section-grid { grid-template-columns: 1fr; gap: 18px; }
  .sec-rail { position: static; display: flex; align-items: baseline; gap: 14px; }
  .sec-rail .label { margin-top: 0; }
}
@media (max-width: 760px) {
  .main-nav { position: fixed; inset-block: var(--header-h) auto; inset-inline: 0; flex-direction: column; background: var(--bg-2); border-bottom: 1px solid var(--line); padding: 12px 22px; gap: 2px; transform: translateY(-130%); transition: transform .28s ease; margin: 0; }
  .main-nav.open { transform: translateY(0); box-shadow: var(--shadow); }
  .main-nav a { padding: 13px 8px; }
  .menu-toggle { display: inline-flex; }
  .tiles, .tiles.three { grid-template-columns: 1fr; }
  .tiles .tile { border-inline-start: 0; }
  .step { grid-template-columns: 44px 1fr; gap: 14px; }
}
@media (max-width: 480px) {
  .brand-name { display: none; }
  .hero-cta .btn { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}