:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-2: #f0f3fa;
  --surface-3: #e9edff;
  --text: #172033;
  --muted: #667085;
  --border: #e4e7ec;
  --primary: #5b4bff;
  --primary-2: #7a6dff;
  --accent: #12b886;
  --warning: #e6a117;
  --danger: #d92d20;
  --shadow: 0 12px 35px rgba(28, 39, 76, .08);
  --radius: 20px;
}

[data-theme="dark"] {
  --bg: #0d1220;
  --surface: #151b2d;
  --surface-2: #1b2338;
  --surface-3: #222b4c;
  --text: #f4f6fb;
  --muted: #a6b0c4;
  --border: #29334b;
  --primary: #8b7fff;
  --primary-2: #a59cff;
  --accent: #39d7a4;
  --warning: #f1bd51;
  --danger: #ff746b;
  --shadow: 0 16px 45px rgba(0, 0, 0, .24);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }

.site-shell { min-height: 100vh; }
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 28px;
  min-height: 74px;
  padding: 10px max(22px, calc((100vw - 1180px)/2));
  background: color-mix(in srgb, var(--surface) 90%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid color-mix(in srgb, var(--border) 82%, transparent);
}
.brand { display: inline-flex; align-items: center; gap: 10px; min-width: max-content; }
.brand-mark {
  width: 38px; height: 38px; display: grid; place-items: center;
  border-radius: 12px; color: #fff; font-weight: 900;
  background: linear-gradient(135deg, var(--primary), #8f66ff);
  box-shadow: 0 8px 20px rgba(91,75,255,.24);
}
.brand-copy { display: grid; line-height: 1.15; }
.brand-copy strong { font-size: 14px; letter-spacing: -.2px; }
.brand-copy small { margin-top: 3px; color: var(--muted); font-size: 11px; }
.desktop-nav { display: flex; justify-content: center; gap: 8px; }
.desktop-nav a {
  padding: 9px 11px; border-radius: 10px; color: var(--muted); font-size: 13px; font-weight: 700;
}
.desktop-nav a:hover, .desktop-nav a.active { background: var(--surface-2); color: var(--text); }
.nav-actions { display: flex; align-items: center; gap: 8px; }
.icon-btn, .account-btn, .btn {
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  border-radius: 12px; font-weight: 800;
}
.icon-btn { width: 40px; height: 40px; display: grid; place-items: center; }
.account-btn { padding: 9px 14px; font-size: 13px; }
.account-btn:hover, .icon-btn:hover { background: var(--surface-2); }
.mobile-only { display: none; }
.mobile-menu {
  position: fixed; top: 74px; left: 12px; right: 12px; z-index: 60;
  padding: 12px; border: 1px solid var(--border); border-radius: 16px;
  background: var(--surface); box-shadow: var(--shadow);
}
.mobile-menu a { display: block; padding: 12px; border-radius: 10px; font-weight: 750; }
.mobile-menu a:hover { background: var(--surface-2); }

.app { width: min(1180px, calc(100% - 34px)); margin: 0 auto; padding: 34px 0 64px; }

.hero {
  position: relative; overflow: hidden;
  display: grid; grid-template-columns: 1.18fr .82fr; gap: 34px;
  min-height: 480px; align-items: center;
  padding: clamp(32px, 5vw, 62px);
  border: 1px solid var(--border); border-radius: 30px;
  background:
    radial-gradient(circle at 88% 12%, rgba(91,75,255,.18), transparent 35%),
    radial-gradient(circle at 10% 90%, rgba(18,184,134,.11), transparent 32%),
    var(--surface);
  box-shadow: var(--shadow);
}
.eyebrow, .pill {
  display: inline-flex; align-items: center; gap: 7px; width: fit-content;
  border: 1px solid var(--border); border-radius: 999px;
  background: var(--surface-2); color: var(--muted); font-size: 12px; font-weight: 850;
}
.eyebrow { padding: 7px 11px; text-transform: uppercase; letter-spacing: .7px; }
.hero h1 { margin: 16px 0 14px; max-width: 760px; font-size: clamp(40px, 6.3vw, 70px); line-height: .98; letter-spacing: -3px; }
.hero h1 span { color: var(--primary); }
.hero p { max-width: 680px; color: var(--muted); font-size: clamp(16px, 2vw, 19px); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.btn { display: inline-flex; justify-content: center; align-items: center; gap: 8px; min-height: 44px; padding: 10px 16px; }
.btn.primary { color: #fff; border-color: var(--primary); background: var(--primary); }
.btn.primary:hover { background: var(--primary-2); }
.btn.secondary:hover { background: var(--surface-2); }
.btn.ghost { background: transparent; border-color: transparent; color: var(--muted); }
.btn.small { min-height: 36px; padding: 7px 11px; font-size: 12px; }
.hero-panel { display: grid; gap: 12px; }
.hero-card { padding: 18px; background: color-mix(in srgb, var(--surface) 88%, var(--primary) 12%); border: 1px solid var(--border); border-radius: 18px; }
.hero-card strong { display: block; font-size: 28px; letter-spacing: -1px; }
.hero-card span { color: var(--muted); font-size: 13px; }
.hero-progress { padding: 22px; background: var(--surface); border: 1px solid var(--border); border-radius: 22px; box-shadow: var(--shadow); }
.hero-progress-top { display: flex; justify-content: space-between; gap: 12px; align-items: center; margin-bottom: 12px; }
.progress-track { width: 100%; height: 10px; border-radius: 99px; background: var(--surface-2); overflow: hidden; }
.progress-fill { height: 100%; width: 0; border-radius: inherit; background: linear-gradient(90deg,var(--primary),var(--accent)); transition: width .35s ease; }

.section { margin-top: 46px; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 18px; margin-bottom: 18px; }
.section-head h2, .page-head h1 { margin: 0; letter-spacing: -1.3px; }
.section-head h2 { font-size: 28px; }
.section-head p, .page-head p { margin: 5px 0 0; color: var(--muted); }
.page-head { margin: 8px 0 28px; }
.page-head h1 { font-size: clamp(34px, 5vw, 50px); }
.page-head .kicker { color: var(--primary); font-weight: 900; text-transform: uppercase; font-size: 12px; letter-spacing: .8px; }

.tool-grid, .topic-grid, .stat-grid, .paper-grid { display: grid; gap: 14px; }
.tool-grid { grid-template-columns: repeat(4, 1fr); }
.topic-grid { grid-template-columns: repeat(2, 1fr); }
.stat-grid { grid-template-columns: repeat(4, 1fr); }
.paper-grid { grid-template-columns: repeat(3, 1fr); }
.tool-card, .topic-card, .stat-card, .paper-card, .panel, .content-card, .form-card {
  border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); box-shadow: 0 6px 20px rgba(28,39,76,.035);
}
.tool-card { padding: 20px; transition: transform .18s ease, box-shadow .18s ease; }
.tool-card:hover, .topic-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.tool-icon { width: 43px; height: 43px; display: grid; place-items: center; border-radius: 13px; background: var(--surface-3); color: var(--primary); font-size: 20px; }
.tool-card h3 { margin: 14px 0 6px; font-size: 17px; }
.tool-card p { color: var(--muted); font-size: 13px; margin: 0; }

.topic-card { display: grid; grid-template-columns: auto 1fr auto; gap: 16px; align-items: start; padding: 20px; transition: transform .18s ease, box-shadow .18s ease; }
.topic-number { width: 48px; height: 48px; display: grid; place-items: center; border-radius: 14px; background: var(--surface-3); color: var(--primary); font-weight: 950; }
.topic-card h3 { margin: 0 0 5px; font-size: 16px; }
.topic-card p { margin: 0; color: var(--muted); font-size: 12px; }
.topic-meta { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 11px; }
.pill { padding: 5px 8px; }
.pill.good { background: color-mix(in srgb, var(--accent) 12%, var(--surface)); color: var(--accent); border-color: color-mix(in srgb, var(--accent) 25%, var(--border)); }
.topic-status { font-size: 20px; color: var(--muted); }

.stat-card { padding: 18px; }
.stat-card strong { display: block; font-size: 28px; letter-spacing: -1px; }
.stat-card span { color: var(--muted); font-size: 12px; }

.panel, .form-card { padding: 22px; }
.panel h3, .form-card h3 { margin: 0 0 13px; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.three-col { display: grid; grid-template-columns: repeat(3,1fr); gap: 14px; }

.topic-hero {
  display: grid; grid-template-columns: 1fr auto; gap: 20px; align-items: end;
  padding: 28px; border-radius: 24px; border: 1px solid var(--border);
  background: radial-gradient(circle at 92% 10%, rgba(91,75,255,.16), transparent 38%), var(--surface);
}
.topic-hero h1 { margin: 7px 0 8px; font-size: clamp(31px,5vw,48px); letter-spacing: -1.8px; line-height: 1.05; }
.topic-hero p { max-width: 800px; color: var(--muted); margin: 0; }
.topic-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.topic-layout { display: grid; grid-template-columns: 250px 1fr; gap: 22px; margin-top: 22px; align-items: start; }
.topic-sidebar { position: sticky; top: 92px; padding: 16px; border: 1px solid var(--border); border-radius: 18px; background: var(--surface); }
.topic-sidebar strong { display: block; margin: 4px 7px 9px; font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: .7px; }
.topic-sidebar a { display: block; padding: 8px; border-radius: 9px; font-size: 12px; font-weight: 700; color: var(--muted); }
.topic-sidebar a:hover { background: var(--surface-2); color: var(--text); }
.topic-content { display: grid; gap: 16px; }
.content-card { padding: clamp(18px,3vw,28px); overflow: hidden; }
.content-card h2 { margin: 0 0 18px; font-size: 25px; letter-spacing: -.7px; }
.content-card h3 { margin: 23px 0 9px; font-size: 17px; }
.content-card p { color: color-mix(in srgb, var(--text) 86%, var(--muted)); }
.content-card ul, .content-card ol { padding-left: 22px; }
.content-card li { margin: 7px 0; }
.content-card.requirements { border-left: 4px solid var(--primary); }
.content-card.mistakes { border-left: 4px solid var(--warning); background: color-mix(in srgb, var(--surface) 94%, var(--warning) 6%); }
.content-card.practical { border-left: 4px solid var(--accent); }
.table-wrap { width: 100%; overflow-x: auto; margin: 14px 0 6px; border: 1px solid var(--border); border-radius: 14px; }
table { width: 100%; min-width: 560px; border-collapse: collapse; background: var(--surface); font-size: 13px; }
th, td { padding: 11px 12px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
th { background: var(--surface-2); font-size: 12px; }
tr:last-child td { border-bottom: 0; }

.paper-card { overflow: hidden; }
.paper-head { padding: 21px; background: var(--surface-3); }
.paper-head span { display: inline-block; font-size: 11px; font-weight: 900; color: var(--primary); text-transform: uppercase; letter-spacing: .8px; }
.paper-head h3 { margin: 4px 0 0; font-size: 20px; }
.paper-body { padding: 20px; }
.paper-big { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 14px; }
.paper-big div { padding: 12px; border-radius: 13px; background: var(--surface-2); }
.paper-big strong { display: block; font-size: 22px; }
.paper-big small { color: var(--muted); }
.paper-body ul { padding-left: 19px; color: var(--muted); font-size: 13px; }

.field-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 12px; }
.field { display: grid; gap: 6px; }
.field.full { grid-column: 1 / -1; }
.field label { font-size: 12px; font-weight: 800; color: var(--muted); }
input, select, textarea {
  width: 100%; min-height: 44px; padding: 10px 12px;
  border: 1px solid var(--border); border-radius: 12px;
  background: var(--surface); color: var(--text); outline: none;
}
input:focus, select:focus, textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 3px color-mix(in srgb,var(--primary) 14%,transparent); }
.input-suffix { position: relative; }
.input-suffix span { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--muted); font-size: 12px; pointer-events: none; }
.input-suffix input { padding-right: 42px; }
.form-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 16px; }
.helper { color: var(--muted); font-size: 12px; }

.result-box { margin-top: 16px; padding: 20px; border-radius: 16px; background: var(--surface-2); border: 1px solid var(--border); }
.result-box strong.big { display: block; font-size: 42px; letter-spacing: -2px; line-height: 1; }
.result-row { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 8px 0; border-bottom: 1px solid var(--border); }
.result-row:last-child { border-bottom: 0; }
.grade-badge { width: 62px; height: 62px; border-radius: 18px; display: grid; place-items: center; background: var(--primary); color: #fff; font-size: 25px; font-weight: 950; }
.notice { padding: 14px 16px; border-radius: 14px; background: color-mix(in srgb,var(--warning) 10%,var(--surface)); border: 1px solid color-mix(in srgb,var(--warning) 25%,var(--border)); color: color-mix(in srgb,var(--text) 80%,var(--warning)); font-size: 12px; }
.notice.info { background: color-mix(in srgb,var(--primary) 8%,var(--surface)); border-color: color-mix(in srgb,var(--primary) 22%,var(--border)); }

.check-grid { display: grid; grid-template-columns: repeat(2,1fr); gap: 8px; }
.check-item { display: flex; gap: 10px; align-items: flex-start; padding: 11px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface); }
.check-item input { width: 18px; min-height: 18px; margin-top: 2px; accent-color: var(--primary); }
.check-item span { font-size: 12px; font-weight: 700; }

.plan-day { margin-top: 12px; padding: 16px; border: 1px solid var(--border); border-radius: 14px; background: var(--surface); }
.plan-day-head { display: flex; justify-content: space-between; gap: 14px; margin-bottom: 8px; }
.plan-day-head strong { font-size: 14px; }
.plan-day-head span { color: var(--muted); font-size: 12px; }
.plan-task { display: flex; gap: 10px; align-items: center; padding: 8px 0; border-top: 1px solid var(--border); }
.plan-task:first-of-type { border-top: 0; }
.plan-task-bullet { width: 8px; height: 8px; border-radius: 50%; background: var(--primary); flex: 0 0 auto; }
.plan-task div { flex: 1; }
.plan-task small { color: var(--muted); }

.login-shell { width: min(920px, 100%); margin: 24px auto 0; display: grid; grid-template-columns: .9fr 1.1fr; overflow: hidden; border-radius: 26px; border: 1px solid var(--border); background: var(--surface); box-shadow: var(--shadow); }
.login-side { padding: 40px; background: linear-gradient(150deg,var(--primary),#8c63ff); color: #fff; }
.login-side h2 { font-size: 34px; line-height: 1.04; letter-spacing: -1.5px; }
.login-side p { color: rgba(255,255,255,.78); }
.login-side ul { padding-left: 18px; color: rgba(255,255,255,.9); }
.login-form { padding: 40px; }
.login-form h1 { margin-top: 0; }
.auth-tabs { display: flex; gap: 7px; margin-bottom: 18px; padding: 4px; border-radius: 12px; background: var(--surface-2); }
.auth-tabs button { flex: 1; padding: 8px; border: 0; border-radius: 9px; background: transparent; color: var(--muted); font-weight: 850; }
.auth-tabs button.active { background: var(--surface); color: var(--text); box-shadow: 0 2px 7px rgba(0,0,0,.05); }

.empty-state { padding: 36px; text-align: center; border: 1px dashed var(--border); border-radius: 18px; color: var(--muted); }
.search-box { position: relative; max-width: 420px; }
.search-box input { padding-left: 38px; }
.search-box::before { content: '⌕'; position: absolute; left: 13px; top: 9px; color: var(--muted); z-index: 2; }

.footer { width: min(1180px, calc(100% - 34px)); margin: 0 auto; padding: 30px 0 40px; border-top: 1px solid var(--border); display: flex; justify-content: space-between; gap: 28px; color: var(--muted); font-size: 12px; }
.footer strong { color: var(--text); }
.footer p { margin: 5px 0 0; }
.footer-meta { display: grid; text-align: right; gap: 4px; }

.toast { position: fixed; bottom: 22px; right: 22px; z-index: 100; transform: translateY(100px); opacity: 0; padding: 12px 15px; border-radius: 12px; color: #fff; background: #111827; box-shadow: var(--shadow); font-weight: 750; font-size: 12px; transition: .25s ease; }
.toast.show { transform: translateY(0); opacity: 1; }

@media (max-width: 980px) {
  .desktop-nav { display: none; }
  .topbar { grid-template-columns: 1fr auto; }
  .mobile-only { display: grid; }
  .hero { grid-template-columns: 1fr; }
  .hero-panel { grid-template-columns: 1fr 1fr; }
  .hero-progress { grid-column: 1/-1; }
  .tool-grid { grid-template-columns: repeat(2,1fr); }
  .paper-grid { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: repeat(2,1fr); }
  .topic-layout { grid-template-columns: 1fr; }
  .topic-sidebar { display: none; }
}

@media (max-width: 680px) {
  .app { width: min(100% - 22px,1180px); padding-top: 18px; }
  .topbar { padding-left: 12px; padding-right: 12px; min-height: 66px; }
  .brand-copy strong { font-size: 12px; }
  .brand-copy small { font-size: 10px; }
  .account-btn { display: none; }
  .mobile-menu { top: 67px; }
  .hero { padding: 26px 20px; min-height: auto; border-radius: 22px; }
  .hero h1 { letter-spacing: -2px; }
  .hero-panel { grid-template-columns: 1fr; }
  .hero-progress { grid-column: auto; }
  .tool-grid, .topic-grid, .stat-grid, .two-col, .three-col, .field-grid, .check-grid { grid-template-columns: 1fr; }
  .field.full { grid-column: auto; }
  .topic-card { grid-template-columns: auto 1fr; }
  .topic-status { grid-column: 2; }
  .topic-hero { grid-template-columns: 1fr; padding: 22px; }
  .topic-actions { justify-content: flex-start; }
  .login-shell { grid-template-columns: 1fr; }
  .login-side { display: none; }
  .login-form { padding: 25px 20px; }
  .footer { flex-direction: column; }
  .footer-meta { text-align: left; }
}

/* V2 additions */
.desktop-nav { gap: 3px; }
.desktop-nav a { padding: 8px 8px; font-size: 12px; }
.hero-metrics { display: grid; grid-template-columns: repeat(2,1fr); gap: 12px; }
.tool-grid-6 { grid-template-columns: repeat(3,1fr); }
.feature-panel { min-height: 210px; display: flex; flex-direction: column; align-items: flex-start; }
.feature-panel h3 { font-size: 24px; letter-spacing: -.7px; margin: 14px 0 8px; }
.feature-panel .btn { margin-top: auto; }
.stat-card small { display:block; margin-top:4px; color:var(--muted); font-size:10px; }

.mini-link-grid { display:grid; grid-template-columns:repeat(2,1fr); gap:10px; }
.mini-link { padding:14px; border:1px solid var(--border); border-radius:14px; background:var(--surface-2); transition:.18s ease; }
.mini-link:hover { transform:translateY(-1px); border-color:color-mix(in srgb,var(--primary) 40%,var(--border)); }
.mini-link strong { display:block; font-size:13px; }
.mini-link span { display:block; color:var(--muted); font-size:11px; margin-top:4px; }

.practical-grid { display:grid; grid-template-columns:repeat(3,1fr); gap:14px; }
.practical-card { padding:19px; border:1px solid var(--border); border-radius:var(--radius); background:var(--surface); box-shadow:0 6px 20px rgba(28,39,76,.035); transition:transform .18s ease,box-shadow .18s ease; }
.practical-card:hover { transform:translateY(-2px); box-shadow:var(--shadow); }
.practical-card-top { display:flex; justify-content:space-between; align-items:center; gap:10px; }
.practical-index { width:42px; height:42px; display:grid; place-items:center; border-radius:13px; background:color-mix(in srgb,var(--accent) 12%,var(--surface)); color:var(--accent); font-weight:950; }
.practical-card h3 { margin:14px 0 6px; font-size:16px; }
.practical-card p { margin:0; color:var(--muted); font-size:12px; }
.practical-hero { background:radial-gradient(circle at 92% 10%,rgba(18,184,134,.15),transparent 38%),var(--surface); }
.paper6-rules ul { columns:2; column-gap:34px; }

.practice-layout { display:grid; grid-template-columns:320px minmax(0,1fr); gap:18px; align-items:start; }
.practice-controls { position:sticky; top:92px; }
.practice-help { display:grid; gap:7px; margin-top:20px; padding-top:16px; border-top:1px solid var(--border); }
.practice-help strong { font-size:12px; text-transform:uppercase; letter-spacing:.6px; color:var(--muted); }
.practice-help span { font-size:12px; }
.question-area { min-width:0; }
.question-empty { min-height:360px; display:grid; place-items:center; align-content:center; gap:8px; background:var(--surface); }
.question-empty h2,.question-empty p { margin:0; }
.question-card { padding:clamp(20px,3vw,30px); border:1px solid var(--border); border-radius:24px; background:var(--surface); box-shadow:var(--shadow); }
.question-top { display:flex; justify-content:space-between; gap:18px; align-items:flex-start; }
.question-top h2 { margin:13px 0 7px; font-size:clamp(24px,3vw,34px); line-height:1.17; letter-spacing:-1px; }
.question-top p { margin:0 0 20px; color:var(--muted); }
.marks { color:var(--primary); white-space:nowrap; font-size:.78em; }
.answer-toolbar { display:flex; flex-wrap:wrap; gap:8px; margin-bottom:10px; }
.file-btn { position:relative; overflow:hidden; }
.file-btn input { position:absolute; inset:0; opacity:0; cursor:pointer; }
#practiceAnswer { min-height:180px; resize:vertical; line-height:1.55; }
.listening { border-color:var(--danger)!important; color:var(--danger)!important; }
.photo-preview { display:flex; gap:12px; align-items:center; margin-top:12px; padding:10px; border:1px solid var(--border); border-radius:14px; background:var(--surface-2); }
.photo-preview img { width:90px; height:70px; object-fit:cover; border-radius:10px; }
.photo-preview div { display:grid; }
.photo-preview span { color:var(--muted); font-size:11px; }
.feedback-box { margin-top:18px; padding:18px; border:1px solid var(--border); border-radius:16px; background:var(--surface-2); }
.feedback-good { background:color-mix(in srgb,var(--accent) 8%,var(--surface)); border-color:color-mix(in srgb,var(--accent) 25%,var(--border)); }
.feedback-score { display:flex; justify-content:space-between; align-items:center; gap:12px; margin-bottom:13px; }
.feedback-score strong { display:block; font-size:34px; letter-spacing:-1.5px; }
.score-ring { width:58px; height:58px; display:grid; place-items:center; border-radius:50%; background:var(--surface); border:5px solid color-mix(in srgb,var(--primary) 30%,var(--border)); font-weight:900; font-size:12px; }
.mark-point-list { display:grid; gap:7px; }
.mark-point { display:flex; gap:10px; align-items:flex-start; padding:9px 10px; border-radius:10px; background:var(--surface); border:1px solid var(--border); }
.mark-point span { width:22px; height:22px; flex:0 0 22px; display:grid; place-items:center; border-radius:50%; font-weight:950; }
.mark-point p { margin:0; font-size:12px; }
.mark-point.hit span { background:color-mix(in srgb,var(--accent) 15%,var(--surface)); color:var(--accent); }
.mark-point.miss span { background:color-mix(in srgb,var(--warning) 14%,var(--surface)); color:var(--warning); }
.model-answer { margin-top:12px; padding-top:10px; border-top:1px solid var(--border); }
.model-answer summary { cursor:pointer; font-weight:800; font-size:12px; }
.model-answer p { font-size:12px; color:var(--muted); }

.calc-main { display:flex; justify-content:space-between; align-items:center; gap:18px; }
.formula-line { padding:18px; border-radius:14px; background:var(--surface-3); color:var(--primary); font-size:clamp(15px,2vw,20px); font-weight:900; letter-spacing:-.3px; }

.planner-grid { display:grid; grid-template-columns:minmax(0,1fr) 310px; gap:18px; align-items:start; }
.planner-side { position:sticky; top:92px; }
.toggle-field { display:flex; flex-direction:column; justify-content:center; gap:10px; padding:9px 0; }
.toggle-field label { display:flex; gap:8px; align-items:center; color:var(--text); }
.toggle-field input { width:17px; min-height:17px; accent-color:var(--primary); }
.planner-check-grid .check-item span { display:grid; gap:2px; }
.planner-check-grid .check-item span small { color:var(--muted); font-size:10px; font-weight:600; }
.planner-estimate { margin-top:16px; }
.estimate-card { display:grid; grid-template-columns:repeat(4,1fr); gap:8px; padding:12px; border-radius:16px; background:var(--surface-2); border:1px solid var(--border); }
.estimate-card div { padding:9px; border-radius:11px; background:var(--surface); }
.estimate-card span { display:block; color:var(--muted); font-size:10px; font-weight:750; }
.estimate-card strong { display:block; margin-top:3px; font-size:18px; }

.weak-list,.mistake-list { display:grid; gap:8px; }
.weak-row { display:flex; justify-content:space-between; align-items:center; gap:14px; padding:11px 12px; border:1px solid var(--border); border-radius:12px; background:var(--surface-2); }
.weak-row div { display:grid; }
.weak-row span { color:var(--muted); font-size:10px; }
.weak-row b { color:var(--primary); }
.mistake-row { padding:10px 12px; border-left:3px solid var(--warning); border-radius:8px; background:var(--surface-2); }
.mistake-row span { color:var(--muted); font-size:10px; font-weight:800; }
.mistake-row p { margin:2px 0 0; font-size:12px; }
.login-eyebrow { background:rgba(255,255,255,.12); border-color:rgba(255,255,255,.25); color:#fff; }

@media (max-width: 1080px) {
  .tool-grid-6 { grid-template-columns:repeat(2,1fr); }
  .practical-grid { grid-template-columns:repeat(2,1fr); }
  .practice-layout,.planner-grid { grid-template-columns:1fr; }
  .practice-controls,.planner-side { position:static; }
}

@media (max-width: 680px) {
  .hero-metrics,.tool-grid-6,.practical-grid,.mini-link-grid,.estimate-card { grid-template-columns:1fr; }
  .paper6-rules ul { columns:1; }
  .question-top,.calc-main { flex-direction:column; }
  .question-top { display:flex; }
  .question-top .pill { align-self:flex-start; }
  .photo-preview { align-items:flex-start; }
}

/* V3 — Core + Extended, persistent practice and visual placeholders */
.sr-only {
  position:absolute!important;
  width:1px!important;
  height:1px!important;
  padding:0!important;
  margin:-1px!important;
  overflow:hidden!important;
  clip:rect(0,0,0,0)!important;
  white-space:nowrap!important;
  border:0!important;
}

.track-select-wrap {
  display:flex;
  align-items:center;
  min-width:112px;
}
.track-select-wrap select {
  width:100%;
  min-height:38px;
  padding:7px 30px 7px 11px;
  border:1px solid var(--border);
  border-radius:12px;
  background:var(--surface);
  color:var(--text);
  font:inherit;
  font-size:12px;
  font-weight:850;
  cursor:pointer;
  outline:none;
}
.track-select-wrap select:focus {
  border-color:var(--primary);
  box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 13%,transparent);
}

.mobile-track-copy {
  display:flex;
  justify-content:space-between;
  align-items:center;
  gap:12px;
  padding:10px 12px 13px;
  margin-bottom:4px;
  color:var(--muted);
  font-size:11px;
  border-bottom:1px solid var(--border);
}
.mobile-track-copy strong { color:var(--primary); }

.hero-route-inline {
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  margin-top:16px;
}
.route-chip {
  border:1px solid var(--border);
  border-radius:999px;
  padding:8px 12px;
  background:var(--surface);
  color:var(--text);
  font-size:11px;
  font-weight:850;
  cursor:pointer;
  transition:.16s ease;
}
.route-chip:hover { transform:translateY(-1px); border-color:color-mix(in srgb,var(--primary) 45%,var(--border)); }
.route-chip.active,
.route-chip.active-state {
  background:color-mix(in srgb,var(--primary) 10%,var(--surface));
  border-color:color-mix(in srgb,var(--primary) 45%,var(--border));
  color:var(--primary);
}

.route-card {
  position:relative;
  overflow:hidden;
  border:1px solid var(--border);
  border-radius:20px;
  background:var(--surface);
  padding:20px;
}
.route-card::after {
  content:"";
  position:absolute;
  width:110px;
  height:110px;
  right:-45px;
  top:-45px;
  border-radius:50%;
  background:color-mix(in srgb,var(--primary) 9%,transparent);
}
.route-card strong { display:block; font-size:17px; margin-bottom:5px; }
.route-card p { margin:0; color:var(--muted); font-size:12px; line-height:1.55; }

.visual-coming,
.visual-question-placeholder {
  border:1px dashed color-mix(in srgb,var(--primary) 42%,var(--border));
  background:linear-gradient(135deg,color-mix(in srgb,var(--primary) 5%,var(--surface)),var(--surface));
  border-radius:18px;
}
.visual-coming {
  display:grid;
  grid-template-columns:auto 1fr;
  gap:14px;
  align-items:start;
  padding:17px;
  margin:15px 0;
}
.visual-icon,
.visual-big-icon {
  display:grid;
  place-items:center;
  background:color-mix(in srgb,var(--primary) 12%,var(--surface));
  color:var(--primary);
  border-radius:14px;
}
.visual-icon { width:42px; height:42px; font-size:18px; }
.visual-big-icon { width:62px; height:62px; margin:0 auto 12px; font-size:25px; }
.visual-coming h3 { margin:0 0 5px; font-size:14px; }
.visual-coming p { margin:0; color:var(--muted); font-size:11px; line-height:1.55; }
.visual-list { display:flex; flex-wrap:wrap; gap:7px; margin-top:10px; }
.visual-list span {
  padding:6px 8px;
  border-radius:9px;
  border:1px solid var(--border);
  background:var(--surface);
  font-size:10px;
  font-weight:750;
}
.visual-question-placeholder {
  text-align:center;
  padding:28px 20px;
  margin:16px 0;
}
.visual-question-placeholder h3 { margin:0 0 7px; font-size:19px; }
.visual-question-placeholder p { max-width:560px; margin:0 auto; color:var(--muted); font-size:12px; line-height:1.55; }
.visual-question { margin-top:15px; }

.question-pills {
  display:flex;
  flex-wrap:wrap;
  gap:7px;
  margin-top:9px;
}
.question-pills .pill { font-size:10px; }
.pool-info {
  margin-top:12px;
  padding:10px 11px;
  border-radius:12px;
  border:1px solid var(--border);
  background:var(--surface-2);
  color:var(--muted);
  font-size:10px;
  line-height:1.5;
}

.mcq-options { display:grid; gap:9px; margin:10px 0 16px; }
.mcq-option {
  display:grid;
  grid-template-columns:32px 1fr;
  gap:10px;
  align-items:center;
  width:100%;
  padding:12px;
  text-align:left;
  border:1px solid var(--border);
  border-radius:13px;
  background:var(--surface);
  color:var(--text);
  cursor:pointer;
  transition:.16s ease;
}
.mcq-option:hover { border-color:color-mix(in srgb,var(--primary) 40%,var(--border)); transform:translateY(-1px); }
.mcq-option.selected {
  border-color:var(--primary);
  background:color-mix(in srgb,var(--primary) 7%,var(--surface));
}
.mcq-letter {
  width:30px;
  height:30px;
  display:grid;
  place-items:center;
  border-radius:9px;
  background:var(--surface-2);
  font-weight:950;
  color:var(--primary);
}

.estimate-card-5 { grid-template-columns:repeat(5,1fr); }
.estimate-card small { display:block; margin-top:2px; color:var(--muted); font-size:9px; line-height:1.35; }

.practice-controls .field select,
.practice-controls .field input,
.practice-controls .field textarea {
  width:100%;
}
.practice-controls .btn { width:100%; justify-content:center; }

@media (max-width: 1180px) {
  .track-select-wrap { min-width:96px; }
  .desktop-nav a { padding-inline:6px; }
}

@media (max-width: 900px) {
  .track-select-wrap { display:none; }
  .estimate-card-5 { grid-template-columns:repeat(2,1fr); }
}

@media (max-width: 680px) {
  .visual-coming { grid-template-columns:1fr; }
  .visual-icon { width:38px; height:38px; }
  .estimate-card-5 { grid-template-columns:1fr; }
  .question-card { border-radius:18px; padding:17px; }
  #practiceAnswer { min-height:150px; }
  .mcq-option { grid-template-columns:30px 1fr; padding:10px; }
}
.mobile-track-copy select {
  min-height:34px;
  padding:5px 24px 5px 9px;
  border:1px solid var(--border);
  border-radius:10px;
  background:var(--surface);
  color:var(--text);
  font:inherit;
  font-size:11px;
  font-weight:850;
}

/* V4 — diagram lab */
.diagram-lab{margin-top:24px}
.diagram-lab-head{align-items:flex-end}
.diagram-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}
.diagram-card{background:var(--surface);border:1px solid var(--border);border-radius:20px;overflow:hidden;box-shadow:var(--shadow-sm)}
.diagram-card-head{display:flex;align-items:flex-start;justify-content:space-between;gap:16px;padding:18px 18px 10px}
.diagram-card-head h3{margin:4px 0 0;font-size:20px}
.diagram-tabs{display:flex;gap:8px;padding:0 18px 12px}
.diagram-tab{appearance:none;border:1px solid var(--border);background:var(--surface-2);color:var(--text);font:inherit;font-weight:800;padding:8px 13px;border-radius:999px;cursor:pointer}
.diagram-tab.active{background:var(--accent);color:#fff;border-color:var(--accent)}
.diagram-frame{background:#f6f9fb;border-top:1px solid var(--border);border-bottom:1px solid var(--border);aspect-ratio:1/1;display:grid;place-items:center;overflow:hidden}
.diagram-frame img{width:100%;height:100%;object-fit:contain;display:block}
.diagram-card-foot{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;padding:11px 16px 14px;color:var(--muted);font-size:12px}
.diagram-note{margin-top:16px}
.diagram-zoom{flex:0 0 auto}
.diagram-modal{position:fixed;inset:0;z-index:9999;display:grid;place-items:center;padding:20px}
.diagram-modal-backdrop{position:absolute;inset:0;background:rgba(4,12,28,.76);backdrop-filter:blur(5px)}
.diagram-modal-card{position:relative;z-index:1;max-width:min(1180px,96vw);max-height:94vh;background:#fff;border-radius:18px;overflow:auto;box-shadow:0 28px 90px rgba(0,0,0,.35)}
.diagram-modal-card img{display:block;max-width:100%;height:auto}
.diagram-modal-close{position:sticky;float:right;top:10px;right:10px;z-index:2;width:38px;height:38px;border:0;border-radius:50%;background:rgba(8,28,51,.92);color:#fff;font-size:26px;line-height:1;cursor:pointer;margin:10px}
body.modal-open{overflow:hidden}
@media(max-width:850px){.diagram-grid{grid-template-columns:1fr}.diagram-frame{aspect-ratio:auto}.diagram-frame img{height:auto}.diagram-card-foot{display:none}}

/* V4 — Mock Exams and readiness diagnostic */
.mock-paper-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
.mock-paper-card{padding:20px;border:1px solid var(--border);border-radius:20px;background:var(--surface);box-shadow:0 6px 20px rgba(28,39,76,.035)}
.mock-paper-card h3{margin:6px 0 10px;font-size:21px}
.mock-paper-card p{color:var(--muted);font-size:13px;line-height:1.55}
.mock-paper-stats{display:flex;gap:7px;flex-wrap:wrap;margin:10px 0 12px}
.mock-paper-stats span{padding:6px 9px;border-radius:999px;background:var(--surface-2);font-size:11px;font-weight:850;color:var(--muted)}
.assessment-shell{max-width:980px;margin:0 auto}
.assessment-topbar{display:flex;justify-content:space-between;align-items:center;gap:16px;margin-bottom:14px;padding:16px 18px;border:1px solid var(--border);border-radius:18px;background:var(--surface);box-shadow:0 6px 20px rgba(28,39,76,.035)}
.assessment-topbar strong{display:block;margin-top:3px}
.assessment-timer{text-align:right;min-width:112px;padding:9px 12px;border-radius:13px;background:var(--surface-3)}
.assessment-timer span{display:block;color:var(--muted);font-size:11px;font-weight:800}
.assessment-timer b{display:block;font-size:24px;color:var(--primary);font-variant-numeric:tabular-nums}
.assessment-timer.diagnostic b{color:var(--accent)}
.assessment-progress{margin-bottom:14px;padding:0 2px}
.assessment-progress>div:first-child{display:flex;justify-content:space-between;gap:16px;margin-bottom:8px;color:var(--muted);font-size:12px;font-weight:800}
.assessment-question{box-shadow:none}
.assessment-options{margin-top:14px}
.assessment-nav{display:flex;justify-content:space-between;gap:10px;margin-top:18px}
.assessment-nav .btn{min-width:130px}
.assessment-submit-row{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-top:14px;padding:13px 2px}
.btn.danger{background:#c93b4d;border-color:#c93b4d;color:#fff}
.btn.danger:hover{filter:brightness(.95)}
.assessment-result-hero{display:grid;grid-template-columns:220px 1fr;gap:24px;align-items:center;padding:24px;border:1px solid var(--border);border-radius:24px;background:linear-gradient(135deg,color-mix(in srgb,var(--primary) 8%,var(--surface)),var(--surface));box-shadow:var(--shadow)}
.assessment-result-hero>div:first-child{display:grid;place-items:center;text-align:center;padding:20px;border-radius:20px;background:var(--surface)}
.assessment-result-hero>div:first-child span,.assessment-result-hero>div:first-child small{color:var(--muted)}
.assessment-result-hero>div:first-child strong{font-size:44px;letter-spacing:-1.5px}
.result-copy h2{margin:0 0 8px;font-size:25px}.result-copy p{color:var(--muted)}
.review-question-list{display:grid;gap:9px}
.review-question{display:grid;grid-template-columns:90px 1fr auto;gap:12px;align-items:center;padding:12px 14px;border:1px solid var(--border);border-radius:13px;background:var(--surface)}
.review-question span{font-size:11px;font-weight:900;color:var(--primary)}.review-question p{margin:0;color:var(--muted);font-size:13px}.review-question strong{font-size:13px}
.history-list{display:grid;gap:9px}
.history-row{display:flex;justify-content:space-between;gap:18px;align-items:center;padding:12px 14px;border:1px solid var(--border);border-radius:13px;background:var(--surface)}
.history-row div{display:grid;gap:2px}.history-row span{font-size:11px;color:var(--muted)}
.readiness-intro{display:grid;grid-template-columns:1fr 240px;gap:28px;align-items:center;padding:28px;border:1px solid var(--border);border-radius:24px;background:linear-gradient(135deg,color-mix(in srgb,var(--accent) 8%,var(--surface)),var(--surface));box-shadow:var(--shadow);margin-bottom:18px}
.readiness-intro h2{font-size:30px;margin:5px 0 8px}.readiness-intro p{color:var(--muted)}
.readiness-feature-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin:18px 0}
.readiness-feature-grid span{padding:9px 10px;border-radius:11px;background:var(--surface);border:1px solid var(--border);font-size:12px;font-weight:800}
.readiness-graphic{aspect-ratio:1/1;border-radius:50%;display:grid;place-items:center;align-content:center;background:var(--surface);border:10px solid color-mix(in srgb,var(--accent) 28%,var(--border));text-align:center}
.readiness-graphic strong{font-size:58px;line-height:.95;color:var(--accent)}.readiness-graphic span{font-weight:950}.readiness-graphic small{color:var(--muted);margin-top:5px}
.readiness-score{display:grid;grid-template-columns:190px 1fr;gap:24px;align-items:center;padding:25px;border:1px solid var(--border);border-radius:24px;background:var(--surface);box-shadow:var(--shadow)}
.readiness-ring{aspect-ratio:1/1;border-radius:50%;display:grid;place-items:center;align-content:center;border:12px solid color-mix(in srgb,var(--primary) 28%,var(--border));background:var(--surface-2)}
.readiness-ring strong{font-size:46px;color:var(--primary)}.readiness-ring span{font-size:12px;font-weight:900;color:var(--muted)}
.readiness-columns{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.readiness-topic{display:flex;justify-content:space-between;gap:12px;align-items:center;padding:10px 11px;border:1px solid var(--border);border-radius:11px;background:var(--surface-2);margin-top:8px;font-size:12px}
.readiness-topic span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.readiness-topic b{flex:0 0 auto}.readiness-topic.strong b{color:var(--accent)}.readiness-topic.weak b{color:var(--warning)}
@media(max-width:900px){.mock-paper-grid{grid-template-columns:1fr}.assessment-result-hero,.readiness-intro,.readiness-score{grid-template-columns:1fr}.readiness-graphic{width:190px;margin:auto}.readiness-ring{width:160px;margin:auto}.readiness-columns{grid-template-columns:1fr}.review-question{grid-template-columns:70px 1fr}.review-question strong{grid-column:2}.assessment-topbar{align-items:flex-start}.assessment-submit-row{align-items:flex-start;flex-direction:column}}
@media(max-width:560px){.readiness-feature-grid{grid-template-columns:1fr}.assessment-topbar{flex-direction:column}.assessment-timer{text-align:left;width:100%}.assessment-nav{display:grid;grid-template-columns:1fr 1fr}.assessment-nav .btn{min-width:0}}
.related-visual-ready{display:grid;gap:7px;margin:14px 0;padding:13px;border-radius:13px;border:1px solid color-mix(in srgb,var(--accent) 25%,var(--border));background:color-mix(in srgb,var(--accent) 8%,var(--surface))}
.related-visual-ready span{color:var(--muted);font-size:12px}
.related-visual-ready .btn{width:max-content;margin-top:4px}