/* =========================================================================
   Tutor Portal — professional gray design language
   Cool-neutral canvas · Inter · thin headings · pill buttons ·
   layered sub-0.1 shadows · hairline borders · cards
   ========================================================================= */

:root {
  --bg:      #ffffff;
  --bg-2:    #f4f4f5;
  --bg-3:    #ececed;
  --bg-4:    #e4e4e7;
  --ink:     #18181b;
  --ink-2:   #3f3f46;
  --ink-3:   #71717a;
  --ink-4:   #a1a1aa;
  --border:  #e2e2e5;
  --border-soft: rgba(0,0,0,0.055);

  /* single accent is slate gray — professional, not colorful */
  --accent:  #3f3f46;
  --accent-ink: #27272a;
  --accent-soft: rgba(63,63,70,0.07);

  --green:  #15803d;  --green-soft:  rgba(21,128,61,0.10);
  --amber:  #a16207;  --amber-soft:  rgba(161,98,7,0.10);
  --red:    #b91c1c;  --red-soft:    rgba(185,28,28,0.10);
  --violet: #52525b;  --violet-soft: rgba(82,82,91,0.10);

  --head: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --body: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;

  --radius: 18px;
  --radius-sm: 12px;
  --radius-xs: 9px;

  --shadow-sm: rgba(0,0,0,0.06) 0px 0px 0px 1px, rgba(0,0,0,0.04) 0px 1px 2px 0px;
  --shadow-md: rgba(0,0,0,0.06) 0px 0px 0px 1px, rgba(0,0,0,0.05) 0px 4px 14px -3px;
  --shadow-lg: rgba(0,0,0,0.08) 0px 0px 0px 1px, rgba(0,0,0,0.07) 0px 20px 44px -14px;

  --sidebar-w: 268px;
  --topbar-h: 62px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0; padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--body);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 { font-family: var(--head); font-weight: 300; letter-spacing: -0.02em; margin: 0; color: var(--ink); }
a { color: inherit; text-decoration: none; }
code { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.88em; background: var(--bg-3); padding: 1px 6px; border-radius: 6px; }
small { font-size: 12.5px; }

/* ------------------------------------------------------------ buttons */
.btn {
  font-family: var(--body);
  font-size: 14.5px;
  font-weight: 500;
  border: 1px solid transparent;
  border-radius: 9999px;
  padding: 10px 20px;
  cursor: pointer;
  transition: background .15s, border-color .15s, transform .05s, color .15s;
  white-space: nowrap;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: #18181b; color: #fff; }
.btn-primary:hover { background: #3f3f46; }
.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: var(--accent-ink); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--border); }
.btn-ghost:hover { border-color: var(--ink-4); background: var(--bg-2); }
.btn-sm { padding: 7px 14px; font-size: 13.5px; }
.btn-block { width: 100%; display: block; }
.btn[disabled] { opacity: .5; cursor: not-allowed; }

.icon-btn {
  background: transparent; border: none; cursor: pointer; font-size: 17px;
  color: var(--ink-2); width: 36px; height: 36px; border-radius: 10px;
  display: inline-flex; align-items: center; justify-content: center;
}
.icon-btn:hover { background: var(--bg-2); }

/* ============================================================ AUTH ==== */
.auth-wrap { min-height: 100vh; display: grid; grid-template-columns: 1fr 1.05fr; }
.auth-card {
  padding: 64px clamp(28px, 6vw, 84px);
  display: flex; flex-direction: column; justify-content: center;
  max-width: 620px; width: 100%;
}
.auth-aside {
  background: linear-gradient(180deg, #f4f4f5, #fff);
  border-left: 1px solid var(--border);
  display: flex; align-items: center; padding: 64px clamp(28px, 6vw, 84px);
}
.aside-inner { max-width: 460px; }
.aside-inner h2 { font-size: clamp(26px, 3vw, 36px); margin-bottom: 22px; }

.brand-row { display: flex; align-items: center; gap: 12px; margin-bottom: 34px; }
.brand-row.small { margin-bottom: 0; }
.logo {
  width: 40px; height: 40px; border-radius: 12px; background: var(--accent);
  color: #fff; display: grid; place-items: center; font-size: 20px; flex: none;
}
.brand-name { font-weight: 600; font-size: 15px; letter-spacing: -0.01em; }
.brand-sub { font-size: 12.5px; color: var(--ink-3); }

.auth-title { font-size: clamp(34px, 4.6vw, 46px); line-height: 1.05; margin-bottom: 14px; }
.auth-lede { color: var(--ink-2); font-size: 15.5px; margin: 0 0 30px; max-width: 44ch; }

.seg {
  display: inline-flex; background: var(--bg-2); border: 1px solid var(--border);
  border-radius: 9999px; padding: 3px; margin-bottom: 24px;
}
.seg-btn {
  border: none; background: transparent; border-radius: 9999px; cursor: pointer;
  padding: 8px 20px; font-size: 14px; font-weight: 500; color: var(--ink-3);
  font-family: var(--body);
}
.seg-btn.active { background: #fff; color: var(--ink); box-shadow: var(--shadow-sm); }

.field { display: block; margin-bottom: 16px; }
.field > span { display: block; font-size: 13px; font-weight: 500; color: var(--ink-2); margin-bottom: 7px; }
.field input {
  width: 100%; font-family: var(--body); font-size: 15px; color: var(--ink);
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 11px 14px; outline: none; transition: border-color .15s, box-shadow .15s;
}
.field input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.err { background: var(--red-soft); color: var(--red); font-size: 13.5px; padding: 10px 14px; border-radius: var(--radius-xs); margin-bottom: 14px; }

.demo-hint {
  margin-top: 26px; padding: 16px 18px; border: 1px dashed var(--border);
  border-radius: var(--radius-sm); font-size: 13px; color: var(--ink-3);
}
.demo-hint strong { display: block; color: var(--ink-2); margin-bottom: 8px; font-size: 12px; text-transform: uppercase; letter-spacing: .06em; }
.demo-hint div { margin: 4px 0; }

.chip {
  display: inline-block; font-size: 12px; font-weight: 600; letter-spacing: .07em;
  text-transform: uppercase; color: var(--accent); background: var(--accent-soft);
  border-radius: 9999px; padding: 5px 13px; margin-bottom: 18px;
}
.aside-list { list-style: none; padding: 0; margin: 22px 0 0; }
.aside-list li {
  display: flex; align-items: center; gap: 12px; padding: 13px 0;
  border-bottom: 1px solid var(--border-soft); font-size: 14.5px;
}
.aside-list .dot { width: 10px; height: 10px; border-radius: 50%; flex: none; }
.aside-list .a-sub { color: var(--ink-3); font-size: 12.5px; }

/* ============================================================ APP ==== */
.app { min-height: 100vh; }
.topbar {
  position: sticky; top: 0; z-index: 40; height: var(--topbar-h);
  display: flex; align-items: center; gap: 14px; padding: 0 22px;
  background: rgba(255,255,255,0.92); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.topbar-right { margin-left: auto; display: flex; align-items: center; gap: 14px; }
.whoami { font-size: 14px; font-weight: 500; color: var(--ink-2); }
.pill { font-size: 11.5px; font-weight: 600; text-transform: uppercase; letter-spacing: .05em; border-radius: 9999px; padding: 4px 11px; }
.role-pill { background: var(--bg-3); color: var(--ink-2); }
.role-pill.tutor { background: var(--accent-soft); color: var(--accent-ink); }
.tutor-status { font-size: 15px; color: var(--ink-4); }
.tutor-status.on { color: var(--green); }
.tutor-status.off { color: var(--red); }

.shell { display: grid; grid-template-columns: var(--sidebar-w) 1fr; min-height: calc(100vh - var(--topbar-h)); }

.sidebar {
  border-right: 1px solid var(--border); background: var(--bg);
  padding: 22px 16px; display: flex; flex-direction: column; gap: 6px;
  position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h)); overflow-y: auto;
}
.nav { display: flex; flex-direction: column; gap: 2px; }
.nav-label { font-size: 11px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--ink-4); padding: 12px 12px 6px; }
.nav-item {
  display: flex; align-items: center; gap: 11px; padding: 9px 12px; border-radius: 10px;
  font-size: 14px; color: var(--ink-2); cursor: pointer; transition: background .12s, color .12s;
}
.nav-item:hover { background: var(--bg-2); }
.nav-item.active { background: var(--bg-3); color: var(--ink); font-weight: 500; }
.ni-ico { width: 18px; text-align: center; color: var(--ink-3); font-size: 13px; }
.nav-item.active .ni-ico { color: var(--accent); }
.nav-dot { width: 8px; height: 8px; border-radius: 50%; flex: none; }
.nav-item .m-pct { margin-left: auto; font-size: 12px; color: var(--ink-4); font-variant-numeric: tabular-nums; }
.side-sep { height: 1px; background: var(--border-soft); margin: 14px 4px; }
.badge { background: var(--accent); color: #fff; font-size: 11px; border-radius: 9999px; padding: 1px 7px; margin-left: auto; font-weight: 600; }

.side-foot { margin-top: auto; padding: 18px 8px 4px; }
.side-foot-title { font-size: 11px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--ink-4); margin-bottom: 6px; }
.ring-wrap { position: relative; width: 120px; height: 120px; margin: 0 auto; }
.ring { transform: rotate(-90deg); }
.ring-bg { fill: none; stroke: var(--bg-3); stroke-width: 10; }
.ring-fg { fill: none; stroke: var(--accent); stroke-width: 10; stroke-linecap: round; stroke-dasharray: 327; stroke-dashoffset: 327; transition: stroke-dashoffset .6s ease; }
.ring-label { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; }
.ring-label span { font-size: 25px; font-weight: 300; letter-spacing: -0.02em; }
.ring-label small { font-size: 11px; color: var(--ink-3); }

.content { padding: 34px clamp(22px, 3.6vw, 52px) 80px; max-width: 1180px; }
.loading { color: var(--ink-3); padding: 40px 0; }

/* -------- page header -------- */
.page-head { margin-bottom: 30px; }
.page-head .eyebrow { font-size: 12px; font-weight: 600; letter-spacing: .07em; text-transform: uppercase; color: var(--accent); margin-bottom: 10px; }
.page-head h1 { font-size: clamp(28px, 3.4vw, 40px); line-height: 1.1; }
.page-head p { color: var(--ink-2); margin: 12px 0 0; max-width: 68ch; }

/* -------- cards / grids -------- */
.grid { display: grid; gap: 18px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-courses { display: grid; gap: 18px; grid-template-columns: repeat(3, 1fr); }

.card {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; transition: border-color .15s, box-shadow .15s, transform .15s;
}
.card.hoverable { cursor: pointer; }
.card.hoverable:hover { border-color: var(--ink-4); box-shadow: var(--shadow-md); transform: translateY(-2px); }
.card-top { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.card h3 { font-size: 19px; margin-bottom: 6px; }
.card .muted { color: var(--ink-3); font-size: 13.5px; }

.stat-card { text-align: left; }
.stat-card .big { font-size: 38px; font-weight: 300; letter-spacing: -0.02em; line-height: 1; }
.stat-card .lbl { color: var(--ink-3); font-size: 13px; margin-top: 6px; }

.course-card { display: flex; flex-direction: column; gap: 14px; }
.course-card .course-head { display: flex; align-items: flex-start; gap: 13px; }
.course-card .cc-dot { width: 12px; height: 12px; border-radius: 50%; margin-top: 6px; flex: none; }
.course-card .cc-code { font-size: 12px; font-weight: 600; letter-spacing: .06em; color: var(--ink-4); text-transform: uppercase; }
.course-card h3 { font-size: 18px; }
.course-card .cc-blurb { color: var(--ink-3); font-size: 13.5px; margin: 0; }
.meter { height: 7px; border-radius: 9999px; background: var(--bg-3); overflow: hidden; }
.meter > i { display: block; height: 100%; border-radius: 9999px; transition: width .5s ease; }
.meter-row { display: flex; align-items: center; gap: 10px; font-size: 12.5px; color: var(--ink-3); }
.meter-row .meter { flex: 1; }

/* -------- unit list -------- */
.unit-row {
  display: flex; align-items: center; gap: 16px; padding: 16px 18px;
  border: 1px solid var(--border); border-radius: var(--radius-sm); margin-bottom: 10px;
  background: var(--bg); cursor: pointer; transition: border-color .15s, box-shadow .15s;
}
.unit-row:hover { border-color: var(--ink-4); box-shadow: var(--shadow-sm); }
.unit-row .u-num { width: 30px; height: 30px; border-radius: 9px; background: var(--bg-3); color: var(--ink-2); display: grid; place-items: center; font-size: 13px; font-weight: 600; flex: none; }
.unit-row .u-main { flex: 1; min-width: 0; }
.unit-row .u-title { font-weight: 500; font-size: 15px; }
.unit-row .u-sum { color: var(--ink-3); font-size: 13px; margin-top: 2px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.unit-row .u-right { display: flex; align-items: center; gap: 12px; flex: none; }
.mini-bar { width: 90px; height: 6px; border-radius: 9999px; background: var(--bg-3); overflow: hidden; }
.mini-bar > i { display: block; height: 100%; }
.u-pct { font-size: 12.5px; color: var(--ink-3); width: 38px; text-align: right; font-variant-numeric: tabular-nums; }

/* -------- unit detail -------- */
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--border); margin: 24px 0 26px; flex-wrap: wrap; }
.tab {
  background: none; border: none; cursor: pointer; font-family: var(--body); font-size: 14.5px;
  color: var(--ink-3); padding: 11px 16px; border-bottom: 2px solid transparent; margin-bottom: -1px;
}
.tab:hover { color: var(--ink); }
.tab.active { color: var(--ink); border-bottom-color: var(--accent); font-weight: 500; }
.tab-panel { display: none; }
.tab-panel.active { display: block; }

.learn-block { margin-bottom: 26px; }
.learn-block h3 { font-size: 20px; margin-bottom: 12px; }
.concept { padding: 14px 0; border-bottom: 1px solid var(--border-soft); }
.concept:last-child { border-bottom: none; }
.concept .c-t { font-weight: 600; font-size: 14.5px; }
.concept .c-d { color: var(--ink-2); font-size: 14px; margin-top: 3px; }

.formula {
  display: flex; align-items: baseline; gap: 14px; padding: 13px 16px; border: 1px solid var(--border);
  border-radius: var(--radius-sm); margin-bottom: 9px; background: var(--bg);
}
.formula .f-name { font-weight: 600; font-size: 13.5px; min-width: 180px; }
.formula .f-eq { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 14.5px; color: var(--accent-ink); background: var(--accent-soft); padding: 3px 10px; border-radius: 8px; }
.formula .f-note { color: var(--ink-3); font-size: 12.5px; margin-left: auto; text-align: right; }

.example-card { background: var(--bg-3); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; }
.example-card h4 { font-size: 15px; margin-bottom: 12px; }
.example-card ol { margin: 0 0 14px; padding-left: 20px; }
.example-card ol li { margin-bottom: 6px; font-size: 14px; color: var(--ink-2); }
.answer-box { background: #fff; border: 1px solid var(--border); border-left: 3px solid var(--accent); border-radius: 10px; padding: 13px 16px; font-size: 14px; }
.answer-box strong { color: var(--accent-ink); }

.trap { display: flex; gap: 11px; padding: 11px 0; font-size: 14px; color: var(--ink-2); }
.trap::before { content: "⚑"; color: var(--amber); flex: none; }
.practice-item { padding: 14px 16px; border: 1px solid var(--border); border-radius: var(--radius-sm); margin-bottom: 10px; }
.practice-q { font-size: 14.5px; }
.reveal-btn { margin-top: 10px; }
.practice-a { margin-top: 10px; font-size: 14px; color: var(--ink-2); background: var(--bg-3); border-radius: 9px; padding: 11px 14px; }

/* -------- flashcard -------- */
.fc-wrap { max-width: 560px; }
.fc {
  perspective: 1200px; height: 300px; margin-bottom: 18px; cursor: pointer;
}
.fc-inner { position: relative; width: 100%; height: 100%; transition: transform .5s; transform-style: preserve-3d; }
.fc.flipped .fc-inner { transform: rotateY(180deg); }
.fc-face {
  position: absolute; inset: 0; backface-visibility: hidden; border-radius: var(--radius);
  display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center;
  padding: 34px; border: 1px solid var(--border);
}
.fc-front { background: var(--bg); }
.fc-back { background: var(--accent-soft); transform: rotateY(180deg); }
.fc-face .fc-kicker { font-size: 11px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--ink-4); margin-bottom: 14px; }
.fc-face .fc-text { font-size: 20px; font-weight: 400; line-height: 1.4; }
.fc-face .fc-text.small { font-size: 16px; font-weight: 300; }
.fc-controls { display: flex; align-items: center; gap: 12px; }
.fc-counter { margin-left: auto; font-size: 13px; color: var(--ink-3); font-variant-numeric: tabular-nums; }

/* -------- study deck: uploaded material as prompt → options → Answer -------- */
.deck-wrap { max-width: 860px; }
.deck-head { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; margin-bottom: 12px; }
.deck-head .fc-counter { margin-left: 0; font-weight: 500; color: var(--ink); }
.deck-actions { display: flex; align-items: center; gap: 8px; margin-top: 14px; }
.opt-correct { border-color: var(--green); background: var(--green-soft); }
.opt-wrong { border-color: var(--red); background: var(--red-soft); }
.opt-correct span, .opt-wrong span { font-weight: 500; }
.why-box { margin-top: 16px; padding: 15px 18px; border-left: 3px solid var(--accent);
           background: var(--bg-2); border-radius: var(--radius-xs); }
.why-head { font-weight: 600; font-size: 14px; margin-bottom: 6px; }
.why-line { font-size: 14.5px; line-height: 1.55; color: var(--ink-2); margin-top: 3px; }

/* auth: plan note + the cancel link */
.plan-note { font-size: 13px; line-height: 1.55; color: var(--ink-3); margin: -2px 0 12px; }
.link-btn { background: none; border: 0; padding: 0; margin-top: 12px; cursor: pointer;
            font-family: var(--body); font-size: 13px; color: var(--ink-3);
            text-decoration: underline; text-underline-offset: 3px; }
.link-btn:hover { color: var(--ink); }

/* diagram that belongs to the question being asked */
.q-figure { margin: 0 0 16px; padding: 12px; text-align: center;
            border: 1px solid var(--border); border-radius: var(--radius-sm); background: var(--bg); }
.q-figure img { display: block; max-width: 100%; height: auto; margin: 0 auto;
                border-radius: var(--radius-xs); }
.q-figure figcaption { margin-top: 8px; font-size: 12.5px; color: var(--ink-3); }

/* -------- quiz -------- */
.quiz-q { border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; margin-bottom: 16px; }
.quiz-q .qq-text { font-size: 15.5px; font-weight: 500; margin-bottom: 14px; }
.opt { display: flex; align-items: center; gap: 12px; padding: 12px 15px; border: 1px solid var(--border); border-radius: var(--radius-xs); margin-bottom: 8px; cursor: pointer; font-size: 14.5px; transition: border-color .12s, background .12s; }
.opt:hover { border-color: var(--ink-4); background: var(--bg-2); }
.opt input { accent-color: var(--accent); }
.opt.sel { border-color: var(--accent); background: var(--accent-soft); }
.opt.right { border-color: var(--green); background: var(--green-soft); }
.opt.wrong { border-color: var(--red); background: var(--red-soft); }
.quiz-explain { margin-top: 12px; font-size: 13.5px; color: var(--ink-2); background: var(--bg-3); border-radius: 9px; padding: 11px 14px; }
.result-banner { border-radius: var(--radius); padding: 22px; margin-bottom: 22px; display: flex; align-items: center; gap: 18px; }
.result-banner.pass { background: var(--green-soft); }
.result-banner.fail { background: var(--amber-soft); }
.result-banner .rb-score { font-size: 40px; font-weight: 300; letter-spacing: -0.02em; }
.result-banner .rb-txt strong { display: block; font-size: 15px; }
.result-banner .rb-txt small { color: var(--ink-2); }

/* -------- tutor chat -------- */
.chat-layout { display: grid; grid-template-columns: 258px 1fr; gap: 20px; height: calc(100vh - var(--topbar-h) - 120px); min-height: 460px; }
.chat-side { border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; overflow-y: auto; }
.chat-side h4 { font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-4); margin-bottom: 12px; }
.chat-sess { padding: 9px 11px; border-radius: 9px; font-size: 13.5px; cursor: pointer; color: var(--ink-2); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.chat-sess:hover { background: var(--bg-2); }
.chat-sess.active { background: var(--bg-3); color: var(--ink); font-weight: 500; }
.chat-main { display: flex; flex-direction: column; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.chat-context { padding: 12px 18px; border-bottom: 1px solid var(--border); display: flex; align-items: center; gap: 12px; flex-wrap: wrap; font-size: 13px; color: var(--ink-3); background: var(--bg-3); }
.chat-context select { font-family: var(--body); font-size: 13px; border: 1px solid var(--border); border-radius: 8px; padding: 5px 10px; background: #fff; color: var(--ink); }
.chat-stream { flex: 1; overflow-y: auto; padding: 22px; display: flex; flex-direction: column; gap: 16px; }
.msg { max-width: 78%; }
.msg .bubble { padding: 12px 16px; border-radius: 16px; font-size: 14.5px; line-height: 1.62; white-space: pre-wrap; overflow-wrap: anywhere; }
.msg.user { align-self: flex-end; }
.msg.user .bubble { background: #18181b; color: #fff; border-bottom-right-radius: 5px; }
.msg.assistant .bubble { background: var(--bg-3); color: var(--ink); border-bottom-left-radius: 5px; }
.msg .role-tag { font-size: 11px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--ink-4); margin-bottom: 5px; }
.msg.user .role-tag { text-align: right; }
.typing { color: var(--ink-3); font-size: 14px; padding: 4px 2px; }
.typing::after { content: "▍"; animation: blink 1s steps(2) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.chat-input { border-top: 1px solid var(--border); padding: 14px; display: flex; gap: 11px; align-items: flex-end; }
.chat-input textarea {
  flex: 1; font-family: var(--body); font-size: 14.5px; resize: none; border: 1px solid var(--border);
  border-radius: 14px; padding: 11px 14px; outline: none; max-height: 160px; min-height: 44px;
}
.chat-input textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

/* -------- table -------- */
.table { width: 100%; border-collapse: collapse; font-size: 14px; }
.table th { text-align: left; font-size: 12px; text-transform: uppercase; letter-spacing: .05em; color: var(--ink-4); font-weight: 600; padding: 9px 12px; border-bottom: 1px solid var(--border); }
.table td { padding: 12px; border-bottom: 1px solid var(--border-soft); }
.table tr:last-child td { border-bottom: none; }
.tag { display: inline-block; font-size: 12px; border-radius: 9999px; padding: 3px 11px; font-weight: 500; }
.tag.ok { background: var(--green-soft); color: var(--green); }
.tag.warn { background: var(--amber-soft); color: var(--amber); }
.tag.bad { background: var(--red-soft); color: var(--red); }
.tag.neutral { background: var(--bg-3); color: var(--ink-2); }

.empty { text-align: center; color: var(--ink-3); padding: 46px 20px; border: 1px dashed var(--border); border-radius: var(--radius); }

/* -------- modal -------- */
.modal-overlay { position: fixed; inset: 0; background: rgba(20,20,20,0.42); z-index: 90; display: none; align-items: center; justify-content: center; padding: 22px; }
.modal-overlay.open { display: flex; }
.modal { background: #fff; border-radius: var(--radius); width: 100%; max-width: 640px; max-height: 86vh; display: flex; flex-direction: column; box-shadow: var(--shadow-lg); }
.modal-head { display: flex; align-items: center; padding: 20px 22px; border-bottom: 1px solid var(--border); }
.modal-head h3 { font-size: 18px; }
.modal-head .icon-btn { margin-left: auto; }
.modal-body { padding: 22px; overflow-y: auto; }

/* -------- difficulty levels -------- */
.lvl { display: inline-flex; align-items: center; gap: 4px; font-size: 11px; font-weight: 600;
       letter-spacing: .03em; border-radius: 9999px; padding: 2px 9px; white-space: nowrap; }
.lvl-1 { background: var(--green-soft); color: var(--green); }
.lvl-2 { background: var(--amber-soft); color: var(--amber); }
.lvl-3 { background: var(--red-soft);   color: var(--red); }
.lvl-dot { display: inline-flex; gap: 3px; margin-left: 2px; }
.lvl-dot i { width: 5px; height: 5px; border-radius: 50%; background: var(--bg-4); display: block; }
.lvl-dot i.on.l1 { background: var(--green); }
.lvl-dot i.on.l2 { background: var(--amber); }
.lvl-dot i.on.l3 { background: var(--red); }
.level-legend { display: flex; gap: 14px; flex-wrap: wrap; font-size: 12.5px; color: var(--ink-3); margin-bottom: 18px; }
.level-legend span { display: inline-flex; align-items: center; gap: 6px; }
.ramp-note { font-size: 12.5px; color: var(--ink-3); display: inline-flex; align-items: center; gap: 6px; }

/* -------- worked-example tiers -------- */
.tier { border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 14px; overflow: hidden; }
.tier-head { display: flex; align-items: center; gap: 12px; padding: 13px 16px; background: var(--bg-2); border-bottom: 1px solid var(--border); }
.tier-head h4 { font-size: 14.5px; font-weight: 600; }
.tier-body { padding: 18px; }

/* -------- terms -------- */
.term-card { display: flex; flex-direction: column; gap: 12px; }
.term-head { display: flex; align-items: center; gap: 12px; }
.term-head h3 { font-size: 17px; }
.term-active { background: var(--accent-soft); color: var(--accent-ink); }
.chip-x { font-size:12px; border:1px solid var(--border); border-radius:9999px; padding:3px 11px; display:inline-flex; gap:7px; align-items:center; background:var(--bg); }
.chip-x button { border:none; background:none; cursor:pointer; color:var(--ink-4); font-size:13px; line-height:1; padding:0 2px; }
.chip-x button:hover { color: var(--red); }
.field select, .field textarea { width: 100%; font-family: var(--body); font-size: 15px; color: var(--ink);
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 11px 14px; outline: none; }
.field select:focus, .field textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.week-row { display: flex; align-items: center; gap: 14px; padding: 11px 14px; border-bottom: 1px solid var(--border-soft); font-size: 14px; }
.week-row:last-child { border-bottom: none; }
.week-num { width: 62px; font-size: 12px; color: var(--ink-4); font-weight: 600; text-transform: uppercase; letter-spacing: .04em; }

/* -------- misc -------- */
.stack > * + * { margin-top: 14px; }
.row { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.row-between { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.spacer { flex: 1; }
.muted { color: var(--ink-3); }
.only-mobile { display: none; }

@media (max-width: 1080px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 900px) {
  .auth-wrap { grid-template-columns: 1fr; }
  .auth-aside { display: none; }
  .shell { grid-template-columns: 1fr; }
  .sidebar { position: fixed; left: 0; top: var(--topbar-h); z-index: 50; width: 280px; transform: translateX(-102%); transition: transform .22s ease; box-shadow: var(--shadow-lg); }
  .sidebar.open { transform: translateX(0); }
  .only-mobile { display: inline-flex; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .chat-layout { grid-template-columns: 1fr; height: auto; }
  .chat-side { display: none; }
  .chat-stream { max-height: 60vh; }
}

/* ---------------------------------------------- Notes -> Study Kit ---- */
.toolbar {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; flex-wrap: wrap; margin: 4px 0 26px;
}
.toolbar .tabs { margin: 0; border-bottom: none; }
.qq-explain {
  margin-top: 12px; padding: 11px 14px; border-left: 3px solid var(--accent);
  background: var(--bg-2); border-radius: 0 var(--radius-xs) var(--radius-xs) 0;
  font-size: 13.5px; color: var(--ink-2);
}
.quiz-q.ok { border-color: var(--green); }
.quiz-q.bad { border-color: var(--red); }
select, textarea, input[type="file"] { font-size: 14.5px; color: var(--ink); }
textarea { line-height: 1.6; }