/* styles.css — class-based, RTL-safe styling for eTutor (team-i18n).
 *
 * Replaces the former inline styles in app.jsx so the layout can mirror under
 * dir="rtl" (ar/he/fa/ur). Directional spacing/alignment uses CSS *logical*
 * properties (margin-inline, padding-inline, inset-inline, text-align:start/end)
 * which flip automatically with the document direction. Genuinely dynamic values
 * (computed colors, bar widths, animation) remain inline in JSX — they are
 * direction-neutral and cannot break RTL.
 */

/* ── palette ─────────────────────────────────────────────────────────────── */
:root {
  --bg: #0d1117; --panel: #161b22; --panel2: #1c232c; --line: #2b333f;
  --ink: #e6edf3; --mute: #8b97a6; --faint: #5b6675;
  --teal: #54f2b2; --amber: #ffb454; --crimson: #ff5d6c; --blue: #6cb6ff; --gold: #e3b341;
}

/* ── base ────────────────────────────────────────────────────────────────── */
html, body { margin: 0; background: var(--bg); color: var(--ink); font-family: 'IBM Plex Mono', monospace; }
* { box-sizing: border-box; }
.nr { font-family: 'Newsreader', Georgia, serif; }
button, input, select, textarea { font-family: inherit; }

/* Script-aware fonts so CJK / Arabic / Devanagari render with coverage. */
:lang(zh) { font-family: 'Noto Sans SC', 'IBM Plex Mono', sans-serif; }
:lang(ja) { font-family: 'Noto Sans JP', 'IBM Plex Mono', sans-serif; }
:lang(ko) { font-family: 'Noto Sans KR', 'IBM Plex Mono', sans-serif; }
:lang(hi) { font-family: 'Noto Sans Devanagari', 'IBM Plex Mono', sans-serif; }
:lang(ar), :lang(he), :lang(fa), :lang(ur) { font-family: 'Noto Sans Arabic', 'IBM Plex Mono', sans-serif; }

.scroll::-webkit-scrollbar { width: 8px; height: 8px; }
.scroll::-webkit-scrollbar-thumb { background: var(--line); border-radius: 8px; }
input[type=range] { -webkit-appearance: none; height: 4px; border-radius: 4px; background: var(--line); outline: none; }
input[type=range]::-webkit-slider-thumb { -webkit-appearance: none; width: 16px; height: 16px; border-radius: 50%; background: var(--teal); cursor: pointer; border: 2px solid var(--bg); }
@keyframes flick { 0%, 100% { opacity: 1; } 50% { opacity: .82; } }

/* ── color/utility helpers ───────────────────────────────────────────────── */
.t-mute { color: var(--mute); } .t-faint { color: var(--faint); } .t-ink { color: var(--ink); }
.t-teal { color: var(--teal); } .t-amber { color: var(--amber); } .t-blue { color: var(--blue); } .t-crimson { color: var(--crimson); }
.app { min-height: 100vh; }
.loading { padding: 40px; color: var(--faint); }
.center-screen { min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 20px; }
.stack { display: grid; gap: 8px; }
.row { display: flex; align-items: center; gap: 10px; }
.row-wrap { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; }
.grow { flex: 1; }
.spacer { flex: 1; }
.muted-note { color: var(--faint); font-size: 11px; }

/* ── buttons ─────────────────────────────────────────────────────────────── */
.btn { background: var(--panel2); color: var(--ink); border: none; border-radius: 6px; padding: 7px 11px; font-size: 12.5px; cursor: pointer; }
.btn:disabled { opacity: .6; cursor: default; }
.btn-primary { background: var(--teal); color: var(--bg); font-weight: 600; }
.btn-warn { background: var(--amber); color: var(--bg); }
.btn-reset { background: var(--line); color: var(--ink); }
.btn-muted { background: var(--panel2); color: var(--mute); }
.btn-danger { background: var(--panel2); color: var(--crimson); }
.btn-clear { background: var(--panel); color: var(--faint); border: 1px solid var(--line); }
.btn-ai { background: var(--panel2); color: var(--teal); border: 1px solid var(--line); font-size: 12px; }
.btn-replace { background: var(--crimson); color: var(--bg); inline-size: 100%; margin-block-start: 4px; }
.btn-outline { border: 1px solid var(--line); }
.btn-block { inline-size: 100%; }
.btn-bold { font-weight: 600; }
.btn-start { text-align: start; }
.btn-tiny { font-size: 11px; padding: 3px 8px; }

/* toggle group (slot select, view-as) */
.toggle { background: var(--panel2); color: var(--mute); border: 1px solid var(--line); }
.toggle.is-active { background: var(--blue); color: var(--bg); border-color: var(--blue); }
.seg { display: flex; border: 1px solid var(--line); border-radius: 6px; overflow: hidden; }
.seg__btn { background: var(--panel2); color: var(--mute); border: none; border-radius: 0; padding: 6px 10px; cursor: pointer; font-size: 12.5px; }
.seg__btn + .seg__btn { border-inline-start: 1px solid var(--line); }
.seg__btn.is-active { background: var(--blue); color: var(--bg); }

/* ── atoms ───────────────────────────────────────────────────────────────── */
.h { font-size: 17px; font-weight: 600; margin-block-end: 12px; }
.h .dim { color: var(--faint); font-weight: 400; font-size: 13px; }
.sub { font-size: 11px; color: var(--mute); text-transform: uppercase; letter-spacing: .08em; margin-block-end: 6px; }
.card { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 18px; }
.card--flush { padding: 0; }
.card-mb-sm { margin-block-end: 12px; }
.span2 { grid-column: span 2; }
.dim { color: var(--faint); font-weight: 400; font-size: 13px; }
.vmid { vertical-align: middle; }
.link { color: var(--blue); cursor: pointer; }
.link--mute { color: var(--mute); cursor: pointer; }
.ok { color: var(--teal); font-size: 12px; margin-block-end: 8px; }
.auth-foot { display: flex; justify-content: space-between; margin-block-start: 10px; font-size: 11.5px; color: var(--faint); }
.pill { font-size: 10.5px; padding: 2px 8px; border-radius: 20px; border: 1px solid var(--line); color: var(--mute); }
.helptext { color: var(--mute); font-size: 12.5px; margin-block-end: 12px; }

.field { inline-size: 100%; background: var(--bg); border: 1px solid var(--line); border-radius: 6px; color: var(--ink); padding: 10px 12px; font-size: 13px; margin-block-end: 12px; }
.select { background: var(--bg); border: 1px solid var(--line); border-radius: 6px; color: var(--ink); padding: 9px 11px; font-size: 13px; }

.err { color: var(--crimson); font-size: 12px; }
.err-box { color: var(--crimson); font-size: 12px; margin-block-end: 12px; border: 1px solid var(--crimson); border-radius: 6px; padding: 8px 10px; }

/* ── meter / gauge ───────────────────────────────────────────────────────── */
.meter { background: var(--panel); border: 1px solid var(--line); border-radius: 6px; padding: 8px 10px; }
.meter__label { font-size: 10px; color: var(--mute); text-transform: uppercase; letter-spacing: .06em; }
.meter__value { font-size: 19px; font-weight: 600; }
.meter__unit { font-size: 11px; color: var(--faint); }
.gauge { text-align: end; }
.gauge__label { font-size: 10px; color: var(--mute); letter-spacing: .1em; }
.gauge__value { font-size: 22px; font-weight: 600; }

/* ── top bar ─────────────────────────────────────────────────────────────── */
.topbar { border-block-end: 1px solid var(--line); padding: 14px 22px; display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.brand { font-size: 22px; font-weight: 600; }
.brand--lg { font-size: 28px; margin-block-end: 4px; }
.brand__sub { color: var(--mute); font-size: 13px; }
.topbar__right { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.usermeta { font-size: 12px; color: var(--mute); }

/* ── circuit lab ─────────────────────────────────────────────────────────── */
.lab { background: var(--bg); color: var(--ink); min-height: 100vh; }
.lab__header { border-block-end: 1px solid var(--line); padding: 16px 20px; display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.lab__title { font-size: 24px; font-weight: 600; }
.lab__summary { color: var(--faint); font-size: 12px; margin-block-start: 2px; }
.lab__tasks { padding: 12px 20px; border-block-end: 1px solid var(--line); display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.lab__goal { padding: 10px 20px; color: var(--amber); font-size: 13px; border-block-end: 1px solid var(--line); background: var(--panel); }
.task-btn { border: 1px solid var(--line); }
.task-btn.is-active { background: var(--teal); color: var(--bg); font-weight: 600; }
.task-btn.is-done { border-color: var(--teal); }

.lab__grid { display: grid; grid-template-columns: minmax(220px, 1fr) minmax(360px, 2fr) minmax(260px, 1.2fr); gap: 1px; background: var(--line); }
.lab__col { background: var(--bg); padding: 18px; }
.lab__col--flex { display: flex; flex-direction: column; }
.lab__col--assess { min-height: 540px; }
.meter-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin-block-start: 12px; }

.range-row { display: flex; align-items: center; gap: 10px; margin-block-end: 16px; }
.range-val { color: var(--amber); inline-size: 54px; text-align: end; }
.range-val--wide { inline-size: 64px; }

.palette-row { display: flex; justify-content: space-between; align-items: center; }
.statusbar { margin-block-start: 12px; padding: 9px 12px; border-radius: 6px; background: var(--panel); font-size: 12.5px; }
.hints { color: var(--mute); font-size: 12px; line-height: 1.5; padding-inline-start: 18px; margin-block-start: 8px; }

.bars { display: grid; gap: 8px; margin-block-end: 14px; }
.bar-head { display: flex; justify-content: space-between; font-size: 12px; margin-block-end: 3px; }
.bar-track { height: 7px; background: var(--panel2); border-radius: 6px; overflow: hidden; }
.bar-fill { height: 100%; transition: width .4s; }

.evidence { flex: 1; overflow-y: auto; border: 1px solid var(--line); border-radius: 6px; background: var(--panel); min-height: 120px; }
.evidence__empty { padding: 14px; color: var(--faint); font-size: 12px; }
.evidence__row { padding: 8px 10px; border-block-end: 1px solid var(--line); display: flex; gap: 8px; font-size: 12px; }
.evidence__verb { inline-size: 78px; flex-shrink: 0; }
.evidence__time { color: var(--faint); font-size: 10px; }
.xapi { background: #0a0d12; border: 1px solid var(--line); border-radius: 6px; padding: 10px; font-size: 10.5px; color: var(--teal); max-height: 150px; overflow: auto; margin-block-end: 10px; }
.footnote { margin-block-start: 10px; font-size: 10.5px; color: var(--faint); line-height: 1.5; }
.between { display: flex; justify-content: space-between; align-items: baseline; }

.schematic { inline-size: 100%; background: #0a0d12; border: 1px solid var(--line); border-radius: 8px; }

/* ── dashboards ──────────────────────────────────────────────────────────── */
.page { padding: 22px; max-width: 1000px; margin-inline: auto; }
.card-mb { margin-block-end: 22px; }
.tutor-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 14px; }
.chip-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 8px; }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; margin-block-end: 22px; }

/* tutor row */
.tutor-row { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; flex-wrap: wrap; }
.tutor-row__main { flex: 1; min-width: 200px; }
.tutor-row__title { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.tutor-row__actions { display: flex; gap: 8px; flex-wrap: wrap; }
.tutor-name { font-size: 17px; font-weight: 600; }

/* concept catalog */
.legend { display: flex; gap: 12px; flex-wrap: wrap; margin-block-end: 12px; }
.legend__item { display: inline-flex; align-items: center; gap: 5px; font-size: 11px; color: var(--faint); }
.fit { font-size: 9.5px; font-weight: 600; border: 1px solid currentColor; border-radius: 4px; padding: 1px 5px; letter-spacing: .04em; text-transform: uppercase; flex-shrink: 0; }
.chip { display: flex; align-items: center; gap: 7px; text-align: start; background: var(--bg); border: 1px solid var(--line); border-radius: 6px; color: var(--ink); padding: 7px 9px; font-size: 12px; cursor: pointer; line-height: 1.35; }
.cat { border-block-start: 1px solid var(--line); }
.cat__head { inline-size: 100%; display: flex; justify-content: space-between; align-items: center; gap: 10px; background: transparent; border: none; color: var(--ink); padding: 11px 2px; cursor: pointer; text-align: start; }
.cat__caret { color: var(--teal); margin-inline-end: 8px; }
.cat__name { font-size: 15px; font-weight: 600; }
.cat__count { color: var(--faint); font-size: 11px; margin-inline-start: 8px; }
.cat__body { padding: 0 2px 14px; }
.cat__blurb { color: var(--faint); font-size: 11.5px; margin-block-end: 9px; }
.cat__ai { display: flex; align-items: center; gap: 10px; margin-block-start: 11px; }

/* login */
.login-card { inline-size: 460px; max-inline-size: 100%; }
.provider-link { display: block; text-align: center; text-decoration: none; font-weight: 600; }
.divider { border-block-start: 1px solid var(--line); margin: 4px 0 16px; padding-block-start: 14px; color: var(--faint); font-size: 11px; }
.role-btn { text-align: start; display: flex; justify-content: space-between; align-items: center; border: 1px solid var(--line); }
.role-btn.is-active { background: var(--blue); color: var(--bg); border-color: var(--blue); }

/* admin */
.user-row { display: flex; justify-content: space-between; padding: 10px 16px; border-block-end: 1px solid var(--line); font-size: 12.5px; }
.kv { font-size: 12.5px; }

/* roster modal */
.modal-overlay { position: fixed; inset: 0; background: rgba(0, 0, 0, .6); display: flex; align-items: center; justify-content: center; padding: 20px; z-index: 10; }
.modal { inline-size: 640px; max-inline-size: 100%; max-block-size: 80vh; overflow: auto; }
.modal--wide { inline-size: 760px; }
.roster-row { border-block-start: 1px solid var(--line); padding: 10px 0; display: flex; justify-content: space-between; align-items: center; gap: 10px; }

.flex-end { display: flex; justify-content: flex-end; margin-block-end: 8px; }

/* language picker */
.lang-select { background: var(--panel2); color: var(--mute); border: 1px solid var(--line); border-radius: 6px; padding: 6px 8px; font-size: 12px; }

/* concept diagram (AI-generated SVG) */
.concept-diagram { margin-block-end: 16px; }
.concept-diagram__svg { background: #0a0d12; border: 1px solid var(--line); border-radius: 8px; overflow: hidden; }
.concept-diagram__svg svg { display: block; width: 100%; height: auto; }

/* difficulty switcher bar (above the lab) */
.difficulty-bar { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; padding: 10px 20px; border-block-end: 1px solid var(--line); background: var(--panel); }
.t-crimson { color: var(--crimson); }

/* generation progress panel */
.gen { margin-block-start: 14px; padding: 14px; border: 1px solid var(--line); border-radius: 8px; background: var(--panel2); }
.gen__head { display: flex; align-items: center; gap: 10px; margin-block-end: 10px; }
.gen__title { font-size: 13px; color: var(--ink); flex: 1; }
.gen__time { font-size: 12px; color: var(--mute); font-variant-numeric: tabular-nums; }
.gen__bar { height: 6px; background: var(--line); border-radius: 6px; overflow: hidden; margin-block-end: 10px; }
.gen__bar-fill { height: 100%; background: var(--teal); transition: width .5s ease; }
.gen__steps { display: grid; gap: 4px; }
.gen__step { font-size: 12px; color: var(--faint); transition: color .3s; }
.gen__step.is-active { color: var(--teal); }
.gen__step.is-done { color: var(--mute); }
.gen__dot { display: inline-block; inline-size: 14px; }
.spinner { inline-size: 14px; block-size: 14px; border: 2px solid var(--line); border-block-start-color: var(--teal); border-radius: 50%; display: inline-block; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* conceptual study view (fit === stretch: not lab-graded) */
.study { padding: 18px 20px; max-width: 760px; }
.study__list { color: var(--mute); font-size: 13px; line-height: 1.6; padding-inline-start: 18px; margin: 6px 0 18px; }
.study__list b { color: var(--ink); }

/* ===================== landing (STEM Bench — pilot) ===================== */
.landing { max-width: 1040px; margin: 0 auto; padding: 0 20px 60px; }
.landing-nav { display: flex; align-items: center; justify-content: space-between; padding: 18px 0; border-block-end: 1px solid var(--line); position: sticky; top: 0; background: var(--bg); z-index: 5; }
.landing-brand { font-size: 20px; font-weight: 600; letter-spacing: .02em; }
.pilot-badge { font-size: 10px; font-weight: 700; letter-spacing: .12em; color: var(--bg); background: var(--amber); border-radius: 4px; padding: 2px 6px; margin-inline-start: 8px; vertical-align: middle; }
.btn-lg { padding: 11px 20px; font-size: 14px; }

.landing-hero { text-align: center; padding: 64px 12px 40px; }
.pilot-tag { display: inline-block; font-size: 11px; letter-spacing: .08em; text-transform: uppercase; color: var(--amber); border: 1px solid var(--line); border-radius: 999px; padding: 5px 14px; margin-block-end: 22px; }
.landing-title { font-size: 56px; font-weight: 700; line-height: 1.05; margin: 0; background: linear-gradient(90deg, var(--teal), var(--blue)); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.landing-tagline { font-size: 19px; color: var(--ink); margin: 12px 0 18px; }
.landing-lede { max-width: 620px; margin: 0 auto 28px; color: var(--mute); font-size: 14.5px; line-height: 1.65; }

.landing-section { padding: 34px 0; border-block-start: 1px solid var(--line); }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.feature-card { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 18px; }
.feature-card__title { color: var(--teal); font-weight: 600; font-size: 14px; margin-block-end: 8px; }
.feature-card__desc { color: var(--mute); font-size: 13px; line-height: 1.55; }

.bench-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin-block-start: 14px; }
.bench-card { background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 16px; transition: transform .15s, border-color .15s; }
.bench-card:hover { transform: translateY(-2px); border-color: var(--faint); }
.bench-card__name { font-weight: 600; font-size: 15px; margin-block-end: 6px; }
.bench-card__desc { color: var(--mute); font-size: 12.5px; line-height: 1.5; }
.bench-card--soon { border-style: dashed; background: transparent; }

.landing-footer { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding-block-start: 28px; margin-block-start: 24px; border-block-start: 1px solid var(--line); color: var(--faint); font-size: 12px; flex-wrap: wrap; }
.landing-back { max-width: 460px; margin: 18px auto -6px; padding: 0 20px; }
@media (max-width: 560px) { .landing-title { font-size: 40px; } }