/* ───────────── Tokens ───────────── */
:root {
  --paper: #FAF8F4; --surface: #FFFFFF; --sunk: #F3F0EA;
  --ink: #13202B; --ink-2: #3B4754; --muted: #6B7480; --line: #E6E1D8; --line-2: #D6CFC3;
  --brand: #1F5F4A; --brand-ink: #174A3A; --brand-soft: #E4EEE8; --on-brand: #FAF8F4;
  --clay: #B4532F; --gold: #B7862B;
  --good: #1F7A4D; --good-soft: #E4F2EA; --bad: #B4382F; --bad-soft: #F9E7E4; --hint: #8A5A00; --hint-soft: #FBF1DC;
  --focus: #2F6FDE;
  --r-sm: 10px; --r: 14px; --r-lg: 20px;
  --sh-1: 0 1px 2px rgba(19,32,43,.06); --sh-2: 0 1px 2px rgba(19,32,43,.04), 0 12px 32px -12px rgba(19,32,43,.14);
  --f-body: "IBM Plex Sans Arabic", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-head: "Readex Pro", "IBM Plex Sans Arabic", system-ui, sans-serif;
  --pattern: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='28' height='28'%3E%3Cpath d='M12.8 1.8l2.4 2.4M15.2 1.8l-2.4 2.4M9.3 5.3l2.4 2.4M11.7 5.3l-2.4 2.4M16.3 5.3l2.4 2.4M18.7 5.3l-2.4 2.4M5.8 8.8l2.4 2.4M8.2 8.8l-2.4 2.4M19.8 8.8l2.4 2.4M22.2 8.8l-2.4 2.4M2.3 12.3l2.4 2.4M4.7 12.3l-2.4 2.4M23.3 12.3l2.4 2.4M25.7 12.3l-2.4 2.4M5.8 15.8l2.4 2.4M8.2 15.8l-2.4 2.4M19.8 15.8l2.4 2.4M22.2 15.8l-2.4 2.4M9.3 19.3l2.4 2.4M11.7 19.3l-2.4 2.4M16.3 19.3l2.4 2.4M18.7 19.3l-2.4 2.4M12.8 22.8l2.4 2.4M15.2 22.8l-2.4 2.4M12.8 12.3l2.4 2.4M15.2 12.3l-2.4 2.4' stroke='black' stroke-width='1.1' fill='none'/%3E%3C/svg%3E");
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #0E141B; --surface: #151D26; --sunk: #0B1016;
    --ink: #E9E6DF; --ink-2: #C4C7CB; --muted: #8D96A0; --line: #24303C; --line-2: #33414F;
    --brand: #5FB592; --brand-ink: #8FD0B4; --brand-soft: #16302A; --on-brand: #0E141B;
    --clay: #E08A64; --gold: #E0B45C;
    --good: #5CC08A; --good-soft: #13291F; --bad: #F07D72; --bad-soft: #2E1716; --hint: #E8B65A; --hint-soft: #2B2312;
    --focus: #7AA7FF;
    --sh-1: none; --sh-2: 0 12px 32px -12px rgba(0,0,0,.6);
    color-scheme: dark;
  }
}

/* ───────────── Base ───────────── */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 16px/1.7 var(--f-body); -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility; }
h1, h2, h3, h4 { font-family: var(--f-head); font-weight: 600; line-height: 1.25; margin: 0 0 .5em; letter-spacing: -.01em; color: var(--ink); }
html[lang="ar"] h1, html[lang="ar"] h2, html[lang="ar"] h3 { letter-spacing: 0; }
h1 { font-size: clamp(1.75rem, 3.4vw, 2.5rem); }
h2 { font-size: clamp(1.35rem, 2.4vw, 1.85rem); }
h3 { font-size: 1.1rem; }
p { margin: 0 0 1em; }
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
:focus-visible { outline: 2.5px solid var(--focus); outline-offset: 2px; border-radius: 6px; }
sup, sub { line-height: 0; }
.i { width: 1.15em; height: 1.15em; flex-shrink: 0; vertical-align: -0.2em; }
html[dir="rtl"] .flip { transform: scaleX(-1); }
.back-ic { transform: scaleX(-1); } html[dir="rtl"] .back-ic { transform: none; }
.muted { color: var(--muted); }
.small { font-size: .875rem; }
.wrap { width: 100%; max-width: 1160px; margin-inline: auto; padding-inline: clamp(16px, 4vw, 32px); }
.section { padding-block: clamp(40px, 7vw, 88px); }
.narrow { max-width: 640px; }
.eyebrow { font: 600 .8rem/1.4 var(--f-head); color: var(--brand); letter-spacing: .04em; margin: 0 0 .6em; display: flex; align-items: center; gap: 8px; }
html[lang="en"] .eyebrow { text-transform: uppercase; letter-spacing: .08em; }
.lead { font-size: 1.15rem; color: var(--ink-2); max-width: 52ch; }
.lead-sm { font-size: 1.05rem; max-width: 60ch; }
.skip { position: absolute; inset-inline-start: 12px; top: -60px; z-index: 100; background: var(--ink); color: var(--paper); padding: 8px 14px; border-radius: 8px; }
.skip:focus { top: 12px; }
main, #app:focus-visible { outline: none; } main { min-height: 60vh; }

/* ───────────── Buttons ───────────── */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; padding: 0 18px; border-radius: var(--r-sm);
  border: 1px solid transparent; font: 600 .95rem/1 var(--f-head); cursor: pointer; text-decoration: none !important; white-space: nowrap;
  transition: background .15s, border-color .15s, color .15s, box-shadow .15s, transform .06s; color: var(--ink); background: transparent; }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn:disabled { cursor: not-allowed; opacity: .45; }
.btn.primary { background: var(--brand); color: var(--on-brand); }
.btn.primary:hover:not(:disabled) { background: var(--brand-ink); }
.btn.secondary { background: var(--surface); border-color: var(--line-2); box-shadow: var(--sh-1); }
.btn.secondary:hover { border-color: var(--ink-2); }
.btn.quiet { color: var(--ink-2); }
.btn.quiet:hover { background: var(--sunk); }
.btn.light { background: var(--paper); color: #13202B; }
.btn.ghost-light { color: #FAF8F4; border-color: rgba(250,248,244,.35); }
.btn.ghost-light:hover { border-color: #FAF8F4; }
.btn.sm { min-height: 36px; padding: 0 12px; font-size: .875rem; }
.btn.lg { min-height: 52px; padding: 0 24px; font-size: 1rem; }
.btn.block { width: 100%; }
.actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.icon-btn { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 10px; color: var(--ink-2); }
.icon-btn:hover { background: var(--sunk); }
.icon-btn .i { width: 22px; height: 22px; }

/* ───────────── Atoms ───────────── */
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg); padding: clamp(18px, 3vw, 28px); box-shadow: var(--sh-1); }
.card.flush { padding: 0; overflow: hidden; }
.pill { display: inline-flex; align-items: center; gap: 6px; padding: 3px 10px; border-radius: 999px; background: var(--brand-soft); color: var(--brand-ink); font: 600 .78rem/1.5 var(--f-head); }
.badge { display: inline-flex; padding: 2px 8px; border-radius: 6px; background: color-mix(in srgb, var(--gold) 16%, transparent); color: var(--gold); font: 600 .72rem/1.6 var(--f-head); vertical-align: middle; }
.badge.muted { background: var(--sunk); color: var(--muted); }
.meta { display: inline-flex; flex-wrap: wrap; align-items: center; color: var(--muted); font-size: .85rem; }
.meta > span { display: inline-flex; align-items: center; gap: 4px; }
.meta > span + span::before { content: ""; width: 3px; height: 3px; border-radius: 50%; background: currentColor; opacity: .6; margin-inline: 8px; }
.s-tile { --c: var(--brand); display: grid; place-items: center; width: 40px; height: 40px; border-radius: 11px; flex-shrink: 0;
  color: var(--c); background: color-mix(in srgb, var(--c) 11%, var(--surface)); border: 1px solid color-mix(in srgb, var(--c) 18%, transparent); }
.s-tile .i { width: 20px; height: 20px; }
.s-tile.sm { width: 30px; height: 30px; border-radius: 8px; } .s-tile.sm .i { width: 16px; height: 16px; }
.s-tile.lg { width: 48px; height: 48px; border-radius: 13px; } .s-tile.lg .i { width: 24px; height: 24px; }
.s-tag { display: inline-flex; align-items: center; gap: 6px; font: 600 .82rem/1 var(--f-head); color: var(--c); padding: 6px 10px; border-radius: 8px; background: color-mix(in srgb, var(--c) 10%, transparent); white-space: nowrap; }
.meter { display: block; flex: 1; height: 6px; border-radius: 99px; background: var(--sunk); overflow: hidden; min-width: 40px; }
html:not([data-x]) .meter { box-shadow: inset 0 0 0 1px var(--line); }
.meter > span { display: block; height: 100%; border-radius: inherit; background: var(--c); transition: width .5s cubic-bezier(.2,.7,.2,1); }
.field { width: 100%; min-height: 46px; padding: 10px 14px; border: 1px solid var(--line-2); border-radius: var(--r-sm); background: var(--surface); color: var(--ink); font: inherit; }
.field.lg { min-height: 56px; font-size: 1.15rem; }
.field:focus, .num-input:focus, .phone-field:focus-within { outline: none; border-color: var(--brand); box-shadow: 0 0 0 4px color-mix(in srgb, var(--brand) 16%, transparent); }
.checks { list-style: none; padding: 0; margin: 20px 0; display: grid; gap: 10px; }
.checks li { display: flex; gap: 10px; align-items: flex-start; }
.checks .i { color: var(--brand); margin-top: .3em; }
.grid3 { display: grid; gap: 16px; grid-template-columns: repeat(auto-fit, minmax(270px, 1fr)); }
.sec-head { max-width: 680px; margin-bottom: 32px; }
.sec-head.left { margin-bottom: 28px; }

/* ───────────── Top bar / footer / tab bar ───────────── */
.topbar { position: sticky; top: 0; z-index: 30; background: color-mix(in srgb, var(--paper) 88%, transparent); backdrop-filter: saturate(1.4) blur(12px); border-bottom: 1px solid var(--line); }
.topbar-in { display: flex; align-items: center; gap: 28px; height: 64px; }
.logo { display: inline-flex; align-items: center; gap: 10px; font: 700 1.25rem/1 var(--f-head); color: var(--ink); text-decoration: none !important; }
.mark { width: 32px; height: 32px; display: block; }
.mark.lg { width: 56px; height: 56px; margin: 0 auto 16px; }
.nav { display: flex; gap: 4px; }
.nav a { color: var(--ink-2); font: 500 .93rem/1 var(--f-head); padding: 10px 12px; border-radius: 8px; text-decoration: none; }
.nav a:hover { background: var(--sunk); }
.nav a[aria-current] { color: var(--ink); box-shadow: inset 0 -2px 0 var(--brand); border-radius: 0; }
.top-actions { margin-inline-start: auto; display: flex; gap: 6px; align-items: center; }
.footer { border-top: 1px solid var(--line); margin-top: 40px; padding-top: 40px; }
.footer-in { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 24px; }
.footer-in h4 { font-size: .85rem; color: var(--muted); font-weight: 600; }
.footer-in a:not(.logo) { display: block; color: var(--ink-2); padding: 3px 0; font-size: .93rem; }
.footer-in .logo { margin-bottom: 12px; }
.footer-base { padding-block: 24px 32px; }
.tabbar { display: none; }

/* ───────────── Hero + demo ───────────── */
.hero { position: relative; border-bottom: 1px solid var(--line); overflow: hidden; }
.hero::before { content: ""; position: absolute; inset: 0; background: var(--brand); opacity: .07; -webkit-mask: var(--pattern) 0 0/28px 28px; mask: var(--pattern) 0 0/28px 28px;
  pointer-events: none; }
.hero::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, var(--paper) 35%, transparent 100%); pointer-events: none; }
html[dir="rtl"] .hero::after { background: linear-gradient(270deg, var(--paper) 35%, transparent 100%); }
.hero-grid { position: relative; z-index: 1; display: grid; grid-template-columns: 1.1fr .9fr; gap: clamp(28px, 5vw, 64px); align-items: center; padding-block: clamp(48px, 8vw, 104px); }
.display { font-size: clamp(2.2rem, 5vw, 3.6rem); font-weight: 600; line-height: 1.12; margin-bottom: 20px; }
html[lang="ar"] .display { line-height: 1.3; }
.trust { list-style: none; padding: 0; margin: 28px 0 0; display: flex; flex-wrap: wrap; gap: 8px 22px; color: var(--muted); font-size: .9rem; }
.trust li { display: flex; align-items: center; gap: 8px; }
.trust .i { color: var(--brand); }
.demo { box-shadow: var(--sh-2); }
.demo-head { display: flex; align-items: center; gap: 10px; margin-bottom: 6px; font-family: var(--f-head); }
.demo-q { font: 600 1rem/1.5 var(--f-head); margin: 16px 0 10px; }
.seg { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.seg-b { min-height: 46px; border: 1px solid var(--line-2); border-radius: var(--r-sm); background: var(--surface); color: var(--ink); font: 600 1.05rem var(--f-head); cursor: pointer; }
.seg-b:hover { border-color: var(--ink-2); }
.seg-b.is-right { border-color: var(--good); background: var(--good-soft); color: var(--good); }
.seg-b.is-wrong { border-color: var(--bad); background: var(--bad-soft); color: var(--bad); }
.demo-fb { display: flex; gap: 10px; align-items: flex-start; margin-top: 12px; font-size: .92rem; padding: 10px 12px; border-radius: var(--r-sm); }
.demo-fb:empty { display: none; }
.demo-fb.good { background: var(--good-soft); color: var(--good); } .demo-fb.bad { background: var(--hint-soft); color: var(--hint); }
.demo-fb .i { margin-top: .25em; }
.demo-fb a { font-weight: 600; color: inherit; text-decoration: underline; }

/* ───────────── Widgets ───────────── */
.widget { background: var(--sunk); border: 1px solid var(--line); border-radius: var(--r); padding: 12px; margin-top: 12px; }
.plot { width: 100%; height: auto; display: block; touch-action: none; cursor: crosshair; user-select: none; }
.plot .axis { stroke: var(--line-2); stroke-width: 1.2; }
.plot .tick { stroke: var(--line-2); }
.plot .tick-l { fill: var(--muted); font: 10px var(--f-body); text-anchor: middle; }
.plot .curve { fill: none; stroke: var(--ink-2); stroke-width: 2.5; }
.plot .tan { stroke: var(--clay); stroke-width: 2.5; stroke-linecap: round; }
.plot .handle { cursor: grab; outline: none; }
.plot .halo { fill: var(--brand); opacity: .14; transition: opacity .15s; }
.plot .handle:hover .halo, .plot .handle:focus .halo { opacity: .28; }
.plot .handle:focus-visible .halo { stroke: var(--focus); stroke-width: 2; opacity: .3; }
.plot .pt { fill: var(--brand); stroke: var(--surface); stroke-width: 2.5; }
.readout { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-top: 8px; }
.readout div { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 6px 10px; display: flex; justify-content: space-between; align-items: baseline; font-size: .85rem; color: var(--muted); }
.readout b { font: 600 1.05rem var(--f-head); color: var(--ink); font-variant-numeric: tabular-nums; }
.readout .hl b { color: var(--clay); }
.ohm { display: grid; grid-template-columns: 1fr auto; gap: 12px; align-items: center; }
.circuit { width: 100%; height: auto; }
.circuit .wire { fill: none; stroke: var(--ink-2); stroke-width: 2; }
.circuit .flow { fill: none; stroke: var(--brand); stroke-width: 3; stroke-dasharray: 3 15; stroke-linecap: round; animation: flow 1s linear infinite; }
@keyframes flow { to { stroke-dashoffset: -36; } }
.circuit .mask { fill: var(--sunk); }
.circuit .comp { fill: none; stroke: var(--ink); stroke-width: 2.2; stroke-linejoin: round; stroke-linecap: round; }
.circuit .batt { stroke-width: 3; }
.circuit .meter-c { fill: var(--surface); stroke: var(--ink); stroke-width: 2; }
.circuit .meter-t { fill: var(--ink); font: 600 14px var(--f-head); text-anchor: middle; }
.circuit .c-lab { fill: var(--muted); font: 600 11px var(--f-head); text-anchor: middle; }
.ohm-read { display: flex; flex-direction: column; align-items: center; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); padding: 12px 16px; min-width: 120px; }
.ohm-read span { font-size: .8rem; color: var(--muted); }
.ohm-read b { font: 600 1.6rem var(--f-head); color: var(--brand); font-variant-numeric: tabular-nums; }
.ohm-read small { color: var(--muted); font-size: .75rem; }
.sl-row { display: grid; grid-template-columns: 7.5em 1fr 4em; gap: 12px; align-items: center; margin-top: 10px; font-size: .9rem; color: var(--ink-2); }
.sl-row b { font: 600 .95rem var(--f-head); text-align: end; font-variant-numeric: tabular-nums; }
input[type="range"] { accent-color: var(--brand); width: 100%; height: 28px; }

/* ───────────── Home sections ───────────── */
.band { background: var(--surface); border-block: 1px solid var(--line); padding-block: clamp(40px, 7vw, 80px); }
.band.alt { background: var(--sunk); }
.tabs { display: flex; gap: 6px; overflow-x: auto; scrollbar-width: none; padding-bottom: 2px; margin-bottom: 16px; }
.tabs::-webkit-scrollbar { display: none; }
.tab { display: inline-flex; align-items: center; gap: 6px; min-height: 40px; padding: 0 14px; border: 1px solid var(--line-2); border-radius: 999px; background: var(--surface); color: var(--ink-2); font: 500 .9rem var(--f-head); cursor: pointer; white-space: nowrap; }
.tab:hover { border-color: var(--ink-2); }
.tab[aria-selected="true"] { background: var(--ink); border-color: var(--ink); color: var(--paper); }
.tabs.small { margin-bottom: 20px; }
.br-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 8px; flex-wrap: wrap; }
.br-head h3 { margin: 0; font-size: 1.2rem; }
.subj-list { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 0 24px; }
.subj-list li { display: flex; gap: 12px; align-items: center; padding: 12px 0; border-bottom: 1px solid var(--line); }
.subj-list b { display: block; font: 600 .98rem var(--f-head); }
.method { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; align-items: center; }
.principles { list-style: none; padding: 0; margin: 0; display: grid; gap: 24px; }
.principles li { display: flex; gap: 16px; }
.principles p { color: var(--muted); margin: 0; }
.p-n { flex-shrink: 0; display: grid; place-items: center; width: 36px; height: 36px; border-radius: 50%; border: 1.5px solid var(--brand); color: var(--brand); font: 600 .95rem var(--f-head); }
.curve-fig { margin: 0; }
.curve-fig svg { width: 100%; height: auto; display: block; }
.curve-fig .axis { stroke: var(--line-2); }
.curve-fig .c-no { fill: none; stroke: var(--muted); stroke-width: 2; stroke-dasharray: 5 5; }
.curve-fig .c-yes { fill: none; stroke: var(--brand); stroke-width: 2.6; stroke-linejoin: round; }
.curve-fig .dot { fill: var(--clay); }
.curve-fig .ax-l { fill: var(--muted); font: 11px var(--f-body); }
.curve-fig figcaption { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 8px; font-size: .85rem; color: var(--muted); margin-top: 10px; }
.lgd { display: inline-block; width: 18px; height: 0; border-top: 2.6px solid var(--brand); margin-inline-start: 8px; }
.lgd-no { border-top: 2px dashed var(--muted); }
.preview { display: grid; grid-template-columns: .9fr 1.1fr; gap: clamp(28px, 5vw, 64px); align-items: center; }
.frame { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg); box-shadow: var(--sh-2); overflow: hidden; }
.frame-bar { display: flex; align-items: center; gap: 6px; padding: 10px 14px; border-bottom: 1px solid var(--line); background: var(--sunk); }
.frame-bar i { width: 9px; height: 9px; border-radius: 50%; background: var(--line-2); }
.frame-bar span { margin-inline-start: auto; margin-inline-end: auto; font-size: .75rem; color: var(--muted); direction: ltr; }
.frame-body { padding: 20px; }
.next-mini { display: flex; align-items: center; gap: 12px; padding: 14px; border: 1px solid var(--line); border-radius: var(--r); margin-bottom: 12px; }
.next-mini > div { flex: 1; } .next-mini b { font-family: var(--f-head); display: block; }
.mini-grid { display: grid; grid-template-columns: .8fr 1.2fr; gap: 12px; }
.mini { border: 1px solid var(--line); border-radius: var(--r); padding: 14px; display: flex; flex-direction: column; gap: 4px; }
.mrow { display: flex; align-items: center; gap: 10px; font-size: .85rem; }
.mrow span:first-child { min-width: 5.5em; }
.mrow small { color: var(--muted); min-width: 3ch; text-align: end; }
.big { font: 600 2.2rem/1.1 var(--f-head); font-variant-numeric: tabular-nums; }
.svc { display: flex; flex-direction: column; color: var(--ink); text-decoration: none !important; transition: border-color .15s, box-shadow .15s; }
a.svc:hover { border-color: var(--line-2); box-shadow: var(--sh-2); }
.svc-ic { display: grid; place-items: center; width: 44px; height: 44px; border-radius: 12px; background: var(--brand-soft); color: var(--brand); margin-bottom: 16px; }
.svc-ic .i { width: 22px; height: 22px; }
.svc p { margin: 0; }
.svc .more { margin-top: auto; padding-top: 16px; color: var(--brand); }
.cta { position: relative; overflow: hidden; display: flex; justify-content: space-between; align-items: center; gap: 24px; flex-wrap: wrap;
  background: #13202B; color: #FAF8F4; border-radius: 24px; padding: clamp(28px, 5vw, 56px); margin-top: 24px; }
.cta::before { content: ""; position: absolute; inset: 0; background: #FAF8F4; opacity: .06; -webkit-mask: var(--pattern) 0 0/28px 28px; mask: var(--pattern) 0 0/28px 28px; }
.cta > * { position: relative; }
.cta h2 { color: #FAF8F4; } .cta p { color: #C9CED3; max-width: 52ch; margin: 0; }
.cta .actions { margin: 0; }

/* ───────────── Subjects ───────────── */
.chips { display: flex; gap: 6px; flex-wrap: wrap; margin: 8px 0 28px; }
.chip { padding: 6px 12px; border-radius: 999px; border: 1px solid var(--line-2); color: var(--ink-2); font: 500 .88rem var(--f-head); text-decoration: none !important; }
.chip:hover { border-color: var(--ink-2); }
.chip[aria-current] { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.subj { display: flex; flex-direction: column; gap: 14px; }
.subj header { display: flex; gap: 14px; align-items: center; }
.subj h3 { margin: 0 0 2px; }
.lessons { list-style: none; padding: 0; margin: 0; border-top: 1px solid var(--line); }
.lessons a { display: flex; align-items: center; gap: 12px; padding: 12px 4px; border-bottom: 1px solid var(--line); color: var(--ink); text-decoration: none; }
.lessons a:hover { background: var(--sunk); }
.lessons a span:nth-child(2) { flex: 1; font-weight: 500; }
.lessons small { color: var(--muted); }
.l-ic { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; border: 1.5px solid var(--line-2); color: var(--ink-2); }
.l-ic .i { width: 13px; height: 13px; }
.l-ic.done { background: var(--good); border-color: var(--good); color: var(--surface); }
.soon-note { display: flex; gap: 8px; align-items: center; margin: 0; }
.subj .btn { align-self: flex-start; margin-top: auto; }

/* ───────────── Onboarding ───────────── */
.ob { display: grid; grid-template-columns: 280px 1fr; gap: clamp(24px, 5vw, 64px); align-items: start; max-width: 960px; }
.stepper { list-style: none; padding: 0; margin: 28px 0 0; display: grid; gap: 4px; }
.stepper li { display: flex; align-items: center; gap: 12px; padding: 8px 0; color: var(--muted); font: 500 .95rem var(--f-head); }
.stepper li span { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; border: 1.5px solid var(--line-2); font-size: .82rem; }
.stepper li.cur { color: var(--ink); } .stepper li.cur span { border-color: var(--brand); color: var(--brand); box-shadow: 0 0 0 4px var(--brand-soft); }
.stepper li.done span { background: var(--brand); border-color: var(--brand); color: var(--on-brand); }
.stepper .i { width: 14px; height: 14px; }
.ob-progress { display: none; }
.ob-card { padding: clamp(22px, 4vw, 40px); }
.q-label { display: block; font: 600 1.3rem/1.4 var(--f-head); margin: 0 0 16px; }
.q-label.sm { font-size: 1rem; margin-top: 28px; margin-bottom: 8px; }
.opts { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 10px; margin-top: 8px; }
.opts.row { grid-template-columns: repeat(4, 1fr); }
.opt { display: flex; align-items: center; gap: 12px; min-height: 56px; padding: 12px 14px; border: 1px solid var(--line-2); border-radius: var(--r); background: var(--surface); color: var(--ink); font: 500 .98rem var(--f-body); text-align: start; cursor: pointer; transition: border-color .12s, background .12s; }
.opt > span:not(.o-m):not(.s-tile) { flex: 1; }
.opt:hover { border-color: var(--ink-2); }
.opt.center { flex-direction: column; justify-content: center; gap: 0; text-align: center; }
.opt.center b { font: 600 1.4rem var(--f-head); }
.o-m { width: 20px; height: 20px; border-radius: 50%; border: 1.5px solid var(--line-2); flex-shrink: 0; position: relative; }
.o-m.box { border-radius: 6px; }
.opt[aria-checked="true"], .opt[aria-pressed="true"] { border-color: var(--brand); background: color-mix(in srgb, var(--brand) 6%, var(--surface)); box-shadow: inset 0 0 0 1px var(--brand); }
.opt[aria-checked="true"] .o-m { border: 6px solid var(--brand); }
.opt[aria-pressed="true"] .o-m { background: var(--brand); border-color: var(--brand); }
.opt[aria-pressed="true"] .o-m::after { content: ""; position: absolute; inset: 3px 5px 5px; border: solid var(--on-brand); border-width: 0 2px 2px 0; transform: rotate(45deg); }
.target { display: flex; flex-direction: column; gap: 8px; margin-top: 16px; }
.target b { font: 600 3rem/1 var(--f-head); color: var(--brand); font-variant-numeric: tabular-nums; }
.ob-actions { display: flex; justify-content: space-between; align-items: center; margin-top: 36px; padding-top: 20px; border-top: 1px solid var(--line); }

/* ───────────── Dashboard ───────────── */
.dash-h { display: flex; justify-content: space-between; align-items: flex-end; gap: 16px; flex-wrap: wrap; margin-bottom: 28px; }
.dash-h h1 { margin-bottom: 4px; }
.dash-h .meta .i { width: 14px; height: 14px; }
.dash-grid { display: grid; grid-template-columns: 1fr 340px; gap: 20px; align-items: start; }
.col { display: grid; gap: 20px; }
.h-sm { font-size: 1.05rem; display: flex; align-items: center; gap: 8px; }
.next { display: grid; gap: 18px; color: var(--ink); text-decoration: none !important; border-inline-start: 4px solid var(--c); transition: box-shadow .15s; }
.next:hover { box-shadow: var(--sh-2); }
.next .eyebrow { margin: 0; color: var(--c); }
.next-row { display: flex; gap: 16px; align-items: center; }
.next h2 { margin: 0 0 4px; font-size: 1.35rem; }
.next .btn { justify-self: start; }
.plan { list-style: none; padding: 0; margin: 0; }
.plan a { display: flex; align-items: center; gap: 14px; padding: 14px 6px; border-top: 1px solid var(--line); color: var(--ink); text-decoration: none; }
.plan li:first-child a { border-top: 0; }
.plan a:hover { background: var(--sunk); }
.plan a > div { flex: 1; } .plan b { display: block; font-weight: 600; }
.p-i { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--sunk); color: var(--ink-2); font: 600 .82rem var(--f-head); }
.chev { color: var(--muted); }
.done-msg { display: flex; gap: 10px; align-items: center; color: var(--good); margin: 0; }
.mastery { list-style: none; padding: 0; margin: 0; display: grid; gap: 4px; }
.mastery li { display: grid; grid-template-columns: auto 8.5em 1fr 5.5em; gap: 12px; align-items: center; padding: 6px 0; font-size: .93rem; }
.mastery small { color: var(--muted); text-align: end; font-variant-numeric: tabular-nums; }
.stat { display: flex; flex-direction: column; gap: 2px; }
.st-ic { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 10px; background: var(--brand-soft); color: var(--brand); margin-bottom: 10px; }
.st-ic.warm { background: color-mix(in srgb, var(--clay) 14%, transparent); color: var(--clay); }
.week { display: grid; grid-template-columns: repeat(7, 1fr); gap: 6px; margin: 14px 0 8px; }
.week span { display: flex; flex-direction: column; align-items: center; gap: 4px; }
.week i { width: 100%; max-width: 26px; aspect-ratio: 1; border-radius: 7px; background: var(--sunk); border: 1px solid var(--line); }
.week .on i { background: var(--clay); border-color: var(--clay); }
.week .today i { box-shadow: 0 0 0 2px var(--surface), 0 0 0 3.5px var(--ink-2); }
.week small { font-size: .7rem; color: var(--muted); }
.rem .btn { margin-top: 4px; }
.reset { justify-self: start; color: var(--muted); }
.empty { text-align: center; padding: 48px 28px; }

/* ───────────── Player (focus mode) ───────────── */
body.focus-mode .topbar, body.focus-mode .footer, body.focus-mode .tabbar { display: none; }
.player { min-height: 100vh; min-height: 100dvh; display: flex; flex-direction: column; }
.player-top { position: sticky; top: 0; z-index: 10; display: flex; align-items: center; gap: 16px; padding: 12px clamp(12px, 3vw, 28px); background: var(--paper); border-bottom: 1px solid var(--line); }
.segments { flex: 1; display: flex; gap: 6px; max-width: 640px; margin-inline: auto; }
.segments span { flex: 1; height: 6px; border-radius: 99px; background: var(--line); overflow: hidden; }
.segments i { display: block; height: 100%; width: 0; background: var(--brand); border-radius: inherit; transition: width .4s cubic-bezier(.2,.7,.2,1); }
.player-main { flex: 1; padding: clamp(24px, 5vw, 48px) clamp(16px, 4vw, 32px) 160px; }
.player-inner { max-width: 660px; margin: 0 auto; }
.step-title { font-size: clamp(1.4rem, 3vw, 1.9rem); margin-bottom: 20px; }
.step-title .count { font: 500 .95rem var(--f-body); color: var(--muted); margin-inline-start: 8px; }
.prose { font-size: 1.08rem; color: var(--ink-2); }
.prose p { color: var(--ink-2); }
.rule { margin: 20px 0; padding: 18px 20px; border-radius: var(--r); background: var(--surface); border: 1px solid var(--line); border-inline-start: 4px solid var(--brand); font: 600 1.2rem/1.6 var(--f-head); color: var(--ink); text-align: center; }
.problem { font: 600 1.15rem/1.6 var(--f-head); padding: 16px 18px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); }
.worked { list-style: none; counter-reset: w; padding: 0; margin: 16px 0 0; }
.worked li { counter-increment: w; position: relative; padding: 12px 0; padding-inline-start: 44px; border-bottom: 1px dashed var(--line); animation: rise .3s ease both; font-size: 1.05rem; }
.worked li::before { content: counter(w); position: absolute; inset-inline-start: 0; top: 11px; width: 28px; height: 28px; border-radius: 50%; display: grid; place-items: center; background: var(--brand-soft); color: var(--brand); font: 600 .85rem var(--f-head); }
.stem { font: 500 1.2rem/1.7 var(--f-head); margin-bottom: 20px; }
.options { display: grid; gap: 10px; }
.option { display: flex; align-items: center; gap: 14px; min-height: 58px; padding: 12px 14px; border: 1px solid var(--line-2); border-radius: var(--r); background: var(--surface); color: var(--ink); font: 400 1.05rem var(--f-body); text-align: start; cursor: pointer; transition: border-color .12s, background .12s, opacity .2s; }
.option:hover:not(:disabled) { border-color: var(--ink-2); }
.option kbd { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 7px; border: 1px solid var(--line-2); background: var(--sunk); font: 600 .8rem var(--f-head); color: var(--muted); flex-shrink: 0; }
.o-t { flex: 1; }
.option[aria-checked="true"] { border-color: var(--brand); box-shadow: inset 0 0 0 1px var(--brand); background: color-mix(in srgb, var(--brand) 5%, var(--surface)); }
.option[aria-checked="true"] kbd { background: var(--brand); border-color: var(--brand); color: var(--on-brand); }
.option.is-right { border-color: var(--good); box-shadow: inset 0 0 0 1px var(--good); background: var(--good-soft); opacity: 1 !important; }
.option.is-right kbd { background: var(--good); border-color: var(--good); color: var(--surface); }
.option.is-wrong { border-color: var(--bad); background: var(--bad-soft); animation: nudge .3s; }
.option:disabled:not(.is-right) { cursor: default; opacity: .55; }
.kbd-hint { margin-top: 14px; font-size: .78rem; color: var(--muted); }
.num-input { width: 100%; max-width: 280px; min-height: 56px; padding: 0 16px; border: 1px solid var(--line-2); border-radius: var(--r); background: var(--surface); color: var(--ink); font: 600 1.35rem var(--f-head); font-variant-numeric: tabular-nums; }
.num-input.is-right { border-color: var(--good); background: var(--good-soft); color: var(--good); }
.num-input.is-wrong { border-color: var(--bad); background: var(--bad-soft); animation: nudge .3s; }
.num-input.is-close { border-color: var(--hint); background: var(--hint-soft); }
.predict { margin-top: 24px; padding-top: 20px; border-top: 1px solid var(--line); }
.predict label { display: block; font: 600 1.05rem/1.6 var(--f-head); margin-bottom: 12px; }
.coach { margin-top: 20px; display: grid; gap: 10px; }
.coach-msg { display: flex; gap: 10px; align-items: flex-start; animation: rise .3s ease both; }
.coach-av { width: 30px; height: 30px; flex-shrink: 0; }
.bubble { background: var(--hint-soft); color: var(--ink); padding: 10px 14px; border-radius: 4px 14px 14px 14px; font-size: .98rem; max-width: 52ch; }
html[dir="rtl"] .bubble { border-radius: 14px 4px 14px 14px; }
.player-bar { position: fixed; inset-inline: 0; bottom: 0; z-index: 20; background: var(--surface); border-top: 1px solid var(--line); padding: 14px clamp(12px, 3vw, 28px) calc(14px + env(safe-area-inset-bottom)); transition: background .2s, border-color .2s; }
.player-bar[data-state="good"] { background: var(--good-soft); border-color: color-mix(in srgb, var(--good) 30%, transparent); }
.player-bar[data-state="bad"] { background: var(--bad-soft); border-color: color-mix(in srgb, var(--bad) 30%, transparent); }
.player-bar[data-state="hint"] { background: var(--hint-soft); border-color: color-mix(in srgb, var(--hint) 30%, transparent); }
.bar-inner { max-width: 760px; margin: 0 auto; display: flex; align-items: center; gap: 16px; }
.bar-fb { flex: 1; display: flex; gap: 12px; align-items: flex-start; min-width: 0; }
.bar-fb b { font: 600 1.05rem var(--f-head); display: block; }
.bar-fb p { margin: 2px 0 0; font-size: .93rem; color: var(--ink-2); }
.fb-ic { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; flex-shrink: 0; color: var(--surface); animation: pop .3s cubic-bezier(.3,1.6,.5,1); }
[data-state="good"] .fb-ic { background: var(--good); } [data-state="bad"] .fb-ic { background: var(--bad); } [data-state="hint"] .fb-ic { background: var(--hint); }
[data-state="good"] .bar-fb b { color: var(--good); } [data-state="bad"] .bar-fb b { color: var(--bad); } [data-state="hint"] .bar-fb b { color: var(--hint); }
.bar-actions { display: flex; gap: 8px; margin-inline-start: auto; }
.bar-actions .b-main { min-width: 150px; min-height: 50px; }
[data-state="good"] .b-main { background: var(--good); } [data-state="bad"] .b-main:not(:disabled) { background: var(--bad); }
.summary { text-align: center; padding-top: 24px; position: relative; }
.ring { width: 140px; height: 140px; transform: rotate(-90deg); display: block; margin: 0 auto; }
.ring-bg { fill: none; stroke: var(--line); stroke-width: 8; }
.ring-fg { fill: none; stroke: var(--brand); stroke-width: 8; stroke-linecap: round; animation: ring 1s .15s cubic-bezier(.2,.7,.2,1) forwards; }
@keyframes ring { to { stroke-dashoffset: var(--off); } }
.ring-ic { position: absolute; top: 24px; inset-inline: 0; height: 140px; display: grid; place-items: center; color: var(--brand); }
.ring-ic .i { width: 40px; height: 40px; }
.summary h1 { margin-top: 20px; }
.sum-stats { display: flex; justify-content: center; gap: 12px; margin: 20px 0 28px; }
.sum-stats div { display: flex; flex-direction: column; min-width: 130px; padding: 14px; border: 1px solid var(--line); border-radius: var(--r); background: var(--surface); }
.sum-stats b { font: 600 1.6rem var(--f-head); }
.sum-stats span { font-size: .85rem; color: var(--muted); }

/* ───────────── Exams / join ───────────── */
.filters { display: flex; flex-wrap: wrap; gap: 12px; margin: 24px 0 16px; }
.filters label { display: grid; gap: 6px; font: 500 .85rem var(--f-head); color: var(--muted); min-width: 220px; }
.tbl { width: 100%; border-collapse: collapse; font-size: .95rem; }
.tbl th { text-align: start; font: 600 .8rem var(--f-head); color: var(--muted); background: var(--sunk); padding: 12px 18px; border-bottom: 1px solid var(--line); }
.tbl td { padding: 14px 18px; border-bottom: 1px solid var(--line); }
.tbl tr:last-child td { border-bottom: 0; }
.dl { display: inline-flex; align-items: center; gap: 6px; font-weight: 600; }
.card.flush + .btn { margin-top: 20px; }
.join { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(24px, 5vw, 64px); align-items: start; }
.tab .i { width: 16px; height: 16px; }
.form { display: grid; gap: 16px; }
.form label { display: grid; gap: 6px; font: 500 .9rem var(--f-head); color: var(--ink-2); }
.form label.check { display: flex; align-items: flex-start; gap: 10px; font: 400 .88rem var(--f-body); color: var(--muted); }
.form label.check input { width: 18px; height: 18px; margin-top: 3px; accent-color: var(--brand); }
.phone-field { display: flex; border: 1px solid var(--line-2); border-radius: var(--r-sm); background: var(--surface); overflow: hidden; }
.phone-field select { border: 0; border-inline-end: 1px solid var(--line); background: var(--sunk); color: var(--ink); font: 500 1rem var(--f-head); padding: 0 10px; }
.phone-field input { flex: 1; border: 0; min-height: 46px; padding: 0 14px; font: 500 1.05rem var(--f-head); background: transparent; color: var(--ink); outline: none; letter-spacing: .03em; }
.form-err { color: var(--bad); font-size: .9rem; margin: 0; min-height: 1.2em; }
.success { text-align: center; padding: 16px 0; }
.success > .i { width: 48px; height: 48px; padding: 10px; border-radius: 50%; background: var(--good-soft); color: var(--good); margin-bottom: 12px; }

/* ───────────── Responsive ───────────── */
@media (max-width: 960px) {
  .hero-grid, .method, .preview, .join { grid-template-columns: 1fr; }
  .hero::after { background: linear-gradient(180deg, var(--paper) 40%, transparent) !important; }
  .dash-grid { grid-template-columns: 1fr; }
  .ob { grid-template-columns: 1fr; }
  .stepper { display: none; } .ob-progress { display: block; margin-top: 16px; }
}
@media (max-width: 760px) {
  body { padding-bottom: calc(64px + env(safe-area-inset-bottom)); }
  body.focus-mode { padding-bottom: 0; }
  .nav { display: none; }
  .topbar-in { height: 56px; }
  .tabbar { display: flex; position: fixed; bottom: 0; inset-inline: 0; z-index: 30; background: color-mix(in srgb, var(--surface) 94%, transparent); backdrop-filter: blur(12px);
    border-top: 1px solid var(--line); padding: 6px 4px calc(6px + env(safe-area-inset-bottom)); }
  .tabbar a { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 2px; color: var(--muted); font: 500 .68rem var(--f-head); text-decoration: none; padding: 4px 0; }
  .tabbar .i { width: 22px; height: 22px; }
  .tabbar a[aria-current] { color: var(--brand); }
  .footer-in { grid-template-columns: 1fr 1fr; } .footer-in > div:first-child { grid-column: 1 / -1; }
  .mastery li { grid-template-columns: auto 1fr 4.5em; } .mastery li .meter { grid-column: 2 / -1; grid-row: 2; }
  .opts.row { grid-template-columns: repeat(2, 1fr); }
  .mini-grid { grid-template-columns: 1fr; }
  .kbd-hint { display: none; }
  .bar-inner { flex-wrap: wrap; }
  .bar-actions { width: 100%; } .bar-actions .b-main { flex: 1; }
  .ohm { grid-template-columns: 1fr; }
  .sl-row { grid-template-columns: 6.5em 1fr 3.5em; }
  .tbl th, .tbl td { padding: 12px; }
}

/* ───────────── Motion ───────────── */
@keyframes rise { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }
@keyframes pop { from { transform: scale(.4); opacity: 0; } to { transform: scale(1); opacity: 1; } }
@keyframes nudge { 30% { transform: translateX(-4px); } 70% { transform: translateX(4px); } }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition: none !important; } .ring-fg { stroke-dashoffset: var(--off); } }