:root {
  --bg: #f6f7f2;
  --surface: #ffffff;
  --surface-2: #eef5f7;
  --ink: #17212b;
  --muted: #64717d;
  --line: #d8e0e2;
  --primary: #0f766e;
  --primary-strong: #0b5f59;
  --accent: #d97706;
  --danger: #b42318;
  --ok-bg: #dff7e8;
  --bad-bg: #fee2e2;
  --shadow: 0 16px 48px rgba(24, 35, 43, 0.09);
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

body {
  margin: 0;
  min-height: 100%;
  color: var(--ink);
  background: var(--bg);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.45;
}

a {
  color: inherit;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 64px;
  padding: 12px clamp(16px, 3vw, 36px);
  background: rgba(246, 247, 242, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  color: #fff;
  background: var(--primary);
  border-radius: 8px;
}

.topnav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-left: auto;
}

.topnav a {
  color: var(--muted);
  font-weight: 700;
  text-decoration: none;
}

.site-footer {
  display: flex;
  justify-content: center;
  gap: 18px;
  padding: 0 16px 28px;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 800;
}

.site-footer a {
  text-decoration: none;
}

.training-page.training-active .site-footer {
  display: none;
}

.logout-form {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-left: auto;
}

.topnav + .logout-form {
  margin-left: 0;
}

.user-chip {
  max-width: 220px;
  overflow: hidden;
  color: var(--muted);
  font-weight: 700;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.page-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 48px;
}

.training-page.training-active .page-shell {
  width: 100%;
  padding: 0;
}

.training-page.training-active {
  height: var(--learn-viewport-height, 100dvh);
  overflow: hidden;
}

.training-page.training-active .student-workspace,
.training-page.training-active .training-main {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.training-page.training-active .account-upgrade,
.training-page.training-active .training-main,
.training-page.training-active .training-sidebar {
  display: none;
}

.learn-shell {
  display: grid;
  position: fixed;
  top: var(--learn-viewport-top, 0);
  right: 0;
  left: 0;
  z-index: 20;
  height: var(--learn-viewport-height, 100dvh);
  max-height: var(--learn-viewport-height, 100dvh);
  min-height: 0;
  grid-template-rows: auto auto minmax(0, 1fr) auto auto;
  gap: 8px;
  padding: 8px;
  background: var(--surface);
  overflow: hidden;
}

.learn-top {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px;
  align-items: center;
  color: var(--primary-strong);
  font-size: 1rem;
  font-weight: 900;
}

.learn-actions {
  display: flex;
  gap: 6px;
}

.learn-actions button {
  width: auto;
  min-height: 44px;
  padding: 0 14px;
  font-size: 1rem;
}

.training-summary {
  display: grid;
  gap: 8px;
  width: 100%;
  font-size: 0.9rem;
  font-weight: 900;
}

.summary-row {
  display: grid;
  grid-template-columns: minmax(92px, 0.8fr) repeat(3, minmax(0, 1fr));
  gap: 8px;
  align-items: center;
  min-height: 42px;
  padding: 9px 12px;
  color: #184b73;
  background: #d7ecff;
  border-radius: 8px;
}

.summary-row strong,
.summary-row span,
.summary-result {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.summary-row span {
  text-align: center;
}

.summary-result {
  min-height: 42px;
  padding: 12px 14px;
  color: var(--muted);
  background: var(--surface-2);
  border-radius: 8px;
  font-size: 1.16rem;
  text-align: center;
}

.summary-result.ok {
  color: #05603a;
  background: var(--ok-bg);
}

.summary-result.bad {
  color: #7a271a;
  background: var(--bad-bg);
}

.learn-problem {
  display: grid;
  min-height: 0;
  place-items: center;
  color: #102a43;
  font-size: clamp(3.2rem, 17vw, 5.2rem);
  font-weight: 950;
  line-height: 1;
  text-align: center;
  overflow-wrap: anywhere;
}

.learn-answer {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
}

.learn-answer input {
  height: 62px;
  font-size: 1.9rem;
  font-weight: 900;
  text-align: center;
}

.learn-answer button {
  width: auto;
  min-height: 62px;
  padding: 0 22px;
  font-size: 1.08rem;
}

@media (min-width: 760px) and (min-height: 640px) {
  .learn-shell {
    grid-template-rows: auto auto auto auto auto;
    align-content: center;
    gap: 18px;
    padding: clamp(24px, 5vh, 72px) clamp(28px, 8vw, 96px);
  }

  .learn-shell > * {
    width: min(860px, 100%);
    justify-self: center;
  }

  .learn-top {
    font-size: 1.12rem;
  }

  .learn-actions button {
    min-height: 52px;
    padding: 0 18px;
    font-size: 1.08rem;
  }

  .training-summary {
    font-size: 0.98rem;
  }

  .summary-row,
  .summary-result {
    min-height: 50px;
    padding: 12px 16px;
  }

  .summary-result {
    font-size: 1.28rem;
  }

  .learn-problem {
    min-height: clamp(220px, 34vh, 360px);
    font-size: clamp(5rem, 9vw, 8.4rem);
  }

  .learn-answer {
    grid-template-columns: minmax(180px, 360px) auto;
    justify-content: center;
  }

  .learn-answer input {
    height: 76px;
    font-size: 2.25rem;
  }

  .learn-answer button {
    min-height: 76px;
    padding: 0 30px;
    font-size: 1.18rem;
  }
}

.training-page.training-active .training-stage {
  min-height: 100svh;
  gap: 6px;
  padding: 6px;
  border: 0;
  border-radius: 0;
  box-shadow: none;
}

.training-page.training-active .stage-topline {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px;
  align-items: center;
  font-size: 0.86rem;
}

.training-page.training-active .stage-actions {
  display: flex;
  gap: 6px;
}

.training-page.training-active .stage-actions button {
  width: auto;
  min-height: 34px;
  padding: 0 10px;
  font-size: 0.86rem;
}

.training-page.training-active .problem-card {
  min-height: calc(100svh - 52px);
  gap: 10px;
  padding: 8px;
  border: 0;
  border-radius: 0;
}

.training-page.training-active .problem-text {
  font-size: 4.2rem;
}

.training-page.training-active .answer-form {
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 6px;
}

.training-page.training-active .answer-form input {
  height: 48px;
  font-size: 1.35rem;
}

.training-page.training-active .answer-form button {
  width: auto;
  min-height: 48px;
  padding: 0 14px;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 12px;
  font-size: clamp(2.2rem, 5vw, 4.6rem);
  line-height: 0.96;
}

h2 {
  margin-bottom: 16px;
  font-size: 1.2rem;
}

h3 {
  margin-bottom: 4px;
}

.eyebrow {
  margin-bottom: 10px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.muted {
  color: var(--muted);
}

.auth-page {
  background:
    linear-gradient(120deg, rgba(15, 118, 110, 0.10), transparent 42%),
    var(--bg);
}

.auth-wrap,
.student-login {
  display: grid;
  min-height: calc(100vh - 130px);
  align-items: center;
  gap: 32px;
}

.auth-wrap {
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 420px);
}

.panel,
.setup-band,
.training-stage,
.account-upgrade,
.student-card,
.table-section {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.panel,
.setup-band,
.training-stage,
.account-upgrade,
.student-card,
.table-section {
  padding: 22px;
}

.auth-panel,
.student-login-panel {
  display: grid;
  gap: 16px;
}

.auth-stack {
  display: grid;
  gap: 12px;
}

.student-login {
  justify-items: center;
  text-align: center;
}

.student-login h1 {
  margin-bottom: 0;
}

.student-login-panel {
  width: min(440px, 100%);
  text-align: left;
}

.school-badge {
  padding: 8px 12px;
  color: var(--primary-strong);
  background: #d8f2ef;
  border: 1px solid #a9dcd6;
  border-radius: 8px;
  font-weight: 900;
}

.register-wrap {
  display: grid;
  gap: 22px;
}

.register-head {
  max-width: 720px;
}

.register-choice {
  display: grid;
  grid-template-columns: repeat(2, minmax(280px, 1fr));
  gap: 18px;
  align-items: start;
}

.register-choice-card {
  display: grid;
  min-height: 170px;
  align-content: start;
  gap: 10px;
  padding: 22px;
  color: var(--ink);
  text-align: left;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.register-choice-card strong {
  font-size: 1.35rem;
}

.register-choice-card span {
  color: var(--muted);
  font-weight: 800;
}

.register-choice-card:hover {
  border-color: var(--primary);
  outline: 3px solid rgba(15, 118, 110, 0.12);
}

.register-form-wrap {
  max-width: 560px;
}

.register-panel h2 {
  margin-bottom: 6px;
}

.register-panel-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px;
  align-items: start;
}

.register-panel-head button {
  width: auto;
}

.legal-page {
  max-width: 860px;
  margin: 0 auto;
}

.legal-page h1 {
  font-size: clamp(2rem, 4vw, 3.6rem);
}

.legal-page p {
  color: #344350;
  font-size: 1.02rem;
}

.legal-block {
  margin-top: 22px;
}

.legal-block h2 {
  margin-bottom: 8px;
}

label {
  display: grid;
  gap: 7px;
  color: #344350;
  font-size: 0.9rem;
  font-weight: 800;
}

input,
select {
  width: 100%;
  height: 44px;
  padding: 0 12px;
  color: var(--ink);
  background: #fbfcfc;
  border: 1px solid #c7d1d4;
  border-radius: 8px;
  font: inherit;
  scroll-margin-bottom: 180px;
}

fieldset {
  min-width: 0;
  margin: 0;
  padding: 0;
  border: 0;
}

legend {
  margin-bottom: 10px;
  color: #344350;
  font-size: 0.9rem;
  font-weight: 900;
}

input:focus,
select:focus {
  outline: 3px solid rgba(15, 118, 110, 0.18);
  border-color: var(--primary);
}

button,
.primary-button,
.secondary-button,
.danger-button,
.icon-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 0 16px;
  border: 1px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  font: inherit;
  font-weight: 900;
  text-decoration: none;
}

.primary-button {
  color: #fff;
  background: var(--primary);
}

.primary-button:hover {
  background: var(--primary-strong);
}

.secondary-button {
  color: var(--primary-strong);
  background: #e3f3f1;
  border-color: #b8ded9;
}

.danger-button {
  color: #fff;
  background: var(--danger);
}

.icon-button {
  width: 42px;
  padding: 0;
  color: var(--ink);
  background: var(--surface);
  border-color: var(--line);
  font-size: 1.2rem;
}

.big {
  min-height: 50px;
  font-size: 1rem;
}

.flash-stack {
  display: grid;
  gap: 10px;
  margin-bottom: 20px;
}

.flash {
  padding: 12px 14px;
  border-radius: 8px;
  font-weight: 800;
}

.flash.error {
  color: #7a271a;
  background: #fee4e2;
}

.flash.success {
  color: #05603a;
  background: #d1fadf;
}

.flash.info {
  color: #184b73;
  background: #d7ecff;
}

.dashboard-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: end;
  gap: 22px;
  margin-bottom: 22px;
}

.dashboard-head h1 {
  font-size: clamp(2rem, 4vw, 3.4rem);
}

.metric-grid {
  display: grid;
  gap: 12px;
}

.metric-grid.compact {
  grid-template-columns: repeat(4, minmax(92px, 1fr));
}

.metric-grid.mini {
  grid-template-columns: repeat(3, minmax(76px, 1fr));
}

.stat-panel .metric-grid.mini {
  grid-template-columns: repeat(2, minmax(96px, 1fr));
}

.metric {
  display: grid;
  min-height: 72px;
  align-content: center;
  padding: 12px;
  background: var(--surface-2);
  border: 1px solid #d4e7eb;
  border-radius: 8px;
}

.metric span {
  font-size: 1.65rem;
  font-weight: 900;
}

.metric small {
  color: var(--muted);
  font-weight: 800;
}

.split-layout {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-bottom: 22px;
}

.split-layout form {
  display: grid;
  align-content: start;
  gap: 14px;
}

.class-account-section {
  margin: 22px 0;
}

.class-account-form {
  display: grid;
  grid-template-columns: repeat(4, minmax(140px, 1fr)) auto;
  gap: 14px;
  align-items: end;
}

.class-account-form h2 {
  grid-column: 1 / -1;
}

.account-management-list {
  display: grid;
  gap: 14px;
}

.account-management-card {
  display: grid;
  gap: 16px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfdfc;
}

.account-management-head {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 18px;
}

.account-management-head h3 {
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.account-management-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
  text-align: right;
}

.account-management-form {
  display: grid;
  grid-template-columns: repeat(5, minmax(120px, 1fr)) auto;
  gap: 12px;
  align-items: end;
}

.account-management-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: flex-end;
}

.table-section {
  margin-top: 22px;
}

.table-wrap {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th,
td {
  padding: 12px 10px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

th {
  color: var(--muted);
  font-size: 0.82rem;
  text-transform: uppercase;
}

code {
  padding: 2px 5px;
  background: #eef2f3;
  border-radius: 6px;
  font-family: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  white-space: nowrap;
}

.student-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.student-card {
  display: grid;
  gap: 16px;
  box-shadow: none;
}

.card-title {
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.card-title span {
  color: var(--muted);
  font-weight: 800;
}

.classroom-list,
.student-admin-form,
.settings-form,
.account-settings-form {
  display: grid;
  gap: 12px;
}

.settings-form {
  grid-template-columns: minmax(220px, 1fr) minmax(220px, auto) auto;
  align-items: end;
}

.account-settings-form {
  max-width: 560px;
}

.settings-page {
  display: grid;
  gap: 18px;
}

.danger-zone {
  border-color: #f3b4ae;
  background: #fff7f7;
}

.check-row {
  display: flex;
  min-height: 44px;
  align-items: center;
  gap: 10px;
  color: #344350;
  font-size: 0.95rem;
}

.check-row input {
  width: 20px;
  height: 20px;
  flex: 0 0 auto;
}

.management-row {
  display: grid;
  grid-template-columns: minmax(180px, 1fr) 110px auto;
  gap: 12px;
  align-items: end;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.row-metric {
  display: grid;
  min-height: 44px;
  align-content: center;
  color: var(--muted);
}

.row-metric span {
  color: var(--ink);
  font-size: 1.35rem;
  font-weight: 900;
}

.row-metric small {
  font-weight: 800;
}

.action-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.inline-form {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin: 0;
}

.status-pill {
  display: inline-flex;
  min-height: 30px;
  align-items: center;
  padding: 0 10px;
  border-radius: 8px;
  font-size: 0.84rem;
  font-weight: 900;
}

.status-pill.ok {
  color: #05603a;
  background: var(--ok-bg);
}

.status-pill.bad {
  color: #7a271a;
  background: var(--bad-bg);
}

.muted-row {
  opacity: 0.72;
}

.wide-actions input,
.wide-actions select {
  min-width: 150px;
}

.weak-list,
.attempt-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.weak-list span,
.attempt-list span {
  padding: 7px 9px;
  background: #f2f4f7;
  border-radius: 8px;
  color: #344350;
  font-size: 0.88rem;
  font-weight: 800;
}

.attempt-list .ok {
  background: var(--ok-bg);
}

.attempt-list .bad {
  background: var(--bad-bg);
}

.student-workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 330px;
  gap: 20px;
  align-items: start;
}

.training-main,
.training-sidebar {
  display: grid;
  gap: 18px;
}

.setup-band {
  display: grid;
  gap: 20px;
}

.setup-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 12px;
  align-items: start;
}

.setup-logout {
  display: none;
  margin: 0;
}

.setup-logout button {
  width: auto;
}

.account-upgrade {
  display: grid;
  grid-template-columns: minmax(220px, 0.8fr) minmax(0, 1.2fr);
  gap: 18px;
  align-items: end;
  background: #fffaf0;
  border-color: #f4d08b;
}

.account-upgrade h2 {
  margin-bottom: 8px;
}

.account-form {
  display: grid;
  grid-template-columns: repeat(3, minmax(130px, 1fr)) auto;
  gap: 12px;
  align-items: end;
}

.compact-upgrade {
  grid-template-columns: minmax(0, 1fr) auto;
}

.setup-band h1 {
  margin-bottom: 0;
}

.setup-form {
  display: grid;
  grid-template-columns: repeat(4, minmax(120px, 1fr));
  gap: 14px;
  align-items: end;
}

.mode-picker {
  display: grid;
  grid-column: 1 / -1;
  gap: 14px;
}

.mode-section {
  display: grid;
  gap: 10px;
  padding: 14px;
  background: #f7faf9;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.mode-section-options {
  background: #ffffff;
}

.mode-section-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
}

.mode-section-title span {
  color: #344350;
  font-size: 0.9rem;
  font-weight: 950;
  text-transform: uppercase;
}

.mode-section-title small {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

.mode-tabs {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.mode-tab {
  display: grid;
  align-content: center;
  justify-content: stretch;
  gap: 5px;
  min-height: 64px;
  padding: 12px;
  color: var(--ink);
  text-align: left;
  background: var(--surface);
  border: 1px solid #c7d1d4;
  border-radius: 8px;
  cursor: pointer;
  box-shadow: none;
}

.mode-tab.active {
  color: #ffffff;
  background: var(--primary);
  border-color: var(--primary);
}

.mode-tab span,
.mode-option strong {
  display: block;
  font-weight: 900;
  line-height: 1.18;
}

.mode-tab small,
.mode-option small {
  display: block;
  margin-top: 3px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 750;
  line-height: 1.24;
}

.mode-tab.active small {
  color: rgba(255, 255, 255, 0.84);
}

.mode-panel {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 10px;
}

.mode-option {
  display: grid;
  position: relative;
  grid-template-columns: minmax(0, 1fr);
  align-items: start;
  min-height: 82px;
  padding: 13px 14px 13px 44px;
  background: #fbfcfc;
  border: 1px solid #c7d1d4;
  border-radius: 8px;
  cursor: pointer;
}

.mode-option input {
  position: absolute;
  opacity: 0;
}

.mode-option::before {
  content: "";
  position: absolute;
  top: 16px;
  left: 14px;
  width: 18px;
  height: 18px;
  background: #ffffff;
  border: 2px solid #9fb1b7;
  border-radius: 999px;
}

.mode-option:has(input:checked) {
  background: #e3f3f1;
  border-color: var(--primary);
  outline: 3px solid rgba(15, 118, 110, 0.14);
}

.mode-option:has(input:checked)::before {
  border-color: var(--primary);
  box-shadow: inset 0 0 0 4px #ffffff;
  background: var(--primary);
}

.setup-form .primary-button {
  min-width: 120px;
}

.training-stage {
  display: grid;
  gap: 18px;
}

.training-finish {
  display: grid;
  gap: 18px;
  max-width: 820px;
  margin: 0 auto;
  text-align: center;
}

.training-finish .training-summary {
  text-align: left;
}

.stage-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  color: var(--primary-strong);
  font-weight: 900;
}

.stage-actions {
  display: flex;
  gap: 8px;
}

.problem-card {
  display: grid;
  gap: 20px;
  min-height: 310px;
  place-items: center;
  padding: clamp(18px, 4vw, 42px);
  background: #e8f3f5;
  border: 1px solid #c4dde2;
  border-radius: 8px;
}

.problem-text {
  width: 100%;
  color: #102a43;
  font-size: clamp(3.2rem, 10vw, 7rem);
  font-weight: 950;
  line-height: 1;
  text-align: center;
  overflow-wrap: anywhere;
}

.answer-form {
  display: grid;
  grid-template-columns: minmax(130px, 220px) auto;
  gap: 10px;
  justify-content: center;
  width: 100%;
}

.answer-form input {
  height: 54px;
  font-size: 1.5rem;
  font-weight: 900;
  text-align: center;
}

.feedback {
  padding: 15px;
  border-radius: 8px;
  font-size: 1.05rem;
  font-weight: 900;
}

.feedback.ok {
  color: #05603a;
  background: var(--ok-bg);
}

.feedback.bad {
  color: #7a271a;
  background: var(--bad-bg);
}

.feedback.info {
  color: #184b73;
  background: #d7ecff;
}

.mode-stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 18px;
}

.mode-stat-card {
  display: grid;
  gap: 16px;
  padding: 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.mode-stat-head h2 {
  margin-bottom: 0;
  font-size: 1.25rem;
}

.mode-stat-block {
  display: grid;
  gap: 10px;
}

.mode-stat-block h3 {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 0.9rem;
  text-transform: uppercase;
}

.empty-state {
  display: grid;
  min-height: 50vh;
  place-items: center;
  text-align: center;
}

[hidden] {
  display: none !important;
}

@media (max-width: 900px) {
  .auth-wrap,
  .dashboard-head,
  .split-layout,
  .account-upgrade,
  .student-workspace {
    grid-template-columns: 1fr;
  }

  .metric-grid.compact {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .setup-form {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .account-form {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .settings-form,
  .class-account-form,
  .account-management-form,
  .compact-upgrade {
    grid-template-columns: 1fr;
  }

  .account-management-head,
  .account-management-actions {
    justify-content: flex-start;
    text-align: left;
  }

  .account-management-head {
    flex-direction: column;
  }

  .management-row {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  body {
    min-height: 100svh;
  }

  .auth-page,
  .student-auth-page {
    min-height: 100svh;
  }

  .auth-page .topbar,
  .student-auth-page .topbar {
    display: none;
  }

  .auth-page .page-shell,
  .student-auth-page .page-shell {
    padding-bottom: max(180px, 38svh);
  }

  .auth-wrap,
  .student-login {
    min-height: auto;
    align-items: start;
    gap: 18px;
  }

  .auth-wrap {
    grid-template-columns: 1fr;
  }

  .register-choice {
    grid-template-columns: 1fr;
  }

  .register-panel-head {
    grid-template-columns: 1fr;
  }

  .register-panel-head button {
    width: 100%;
  }

  .auth-copy h1 {
    font-size: 2rem;
  }

  .auth-panel,
  .student-login-panel {
    gap: 14px;
  }

  .auth-panel input,
  .student-login-panel input {
    height: 50px;
    font-size: 1rem;
  }

  .auth-panel button,
  .student-login-panel button {
    min-height: 52px;
  }

  .topbar {
    gap: 10px;
  }

  .user-chip {
    display: none;
  }

  .topbar {
    align-items: flex-start;
    flex-wrap: wrap;
  }

  .training-page .topbar {
    display: none;
  }

  .topnav {
    order: 3;
    width: 100%;
    margin-left: 0;
  }

  .topnav a {
    min-height: 34px;
    padding: 7px 10px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 8px;
  }

  .page-shell {
    width: min(100% - 16px, 1180px);
    padding-top: 16px;
  }

  .training-page .page-shell {
    width: 100%;
    padding: 0;
  }

  .training-page .student-workspace {
    gap: 0;
  }

  .training-page .training-main {
    gap: 0;
  }

  .training-page .account-upgrade,
  .training-page .training-sidebar {
    display: none;
  }

  .training-page .setup-band {
    border-width: 0 0 1px;
    border-radius: 0;
    box-shadow: none;
  }

  .training-page .setup-head {
    grid-template-columns: 1fr auto;
    padding: 8px 8px 0;
  }

  .training-page .setup-head > div {
    display: none;
  }

  .training-page .setup-logout button {
    min-height: 36px;
    padding: 0 12px;
    font-size: 0.9rem;
  }

  .training-page .setup-logout {
    display: block;
  }

  .training-page .mode-tabs {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 6px;
  }

  .training-page .mode-picker {
    gap: 8px;
  }

  .training-page .mode-section {
    gap: 6px;
    padding: 8px;
    border-radius: 8px;
  }

  .training-page .mode-section-title {
    display: none;
  }

  .training-page .mode-tab {
    min-height: 44px;
    padding: 8px;
  }

  .training-page .mode-tab small,
  .training-page .mode-option small {
    display: none;
  }

  .training-page .mode-panel {
    grid-template-columns: 1fr;
    gap: 6px;
  }

  .training-page .mode-option {
    min-height: 42px;
    padding: 8px 8px 8px 34px;
  }

  .training-page .mode-option::before {
    top: 11px;
    left: 10px;
    width: 14px;
    height: 14px;
  }

  .training-page.training-active .page-shell {
    height: var(--learn-viewport-height, 100dvh);
  }

  .learn-shell {
    gap: 10px;
    padding: 8px;
  }

  .learn-top {
    font-size: 1.05rem;
  }

  .learn-actions button {
    min-height: 50px;
    padding: 0 16px;
    font-size: 1.05rem;
  }

  .training-summary {
    gap: 6px;
    font-size: 0.84rem;
  }

  .summary-row {
    grid-template-columns: minmax(78px, 0.9fr) repeat(3, minmax(0, 1fr));
    gap: 5px;
  }

  .summary-row,
  .summary-result {
    min-height: 44px;
    padding: 8px 9px;
  }

  .summary-result {
    min-height: 50px;
    padding: 11px 10px;
    font-size: 1.12rem;
  }

  .summary-row strong,
  .summary-row span {
    overflow: visible;
    line-height: 1.1;
    text-overflow: clip;
    white-space: normal;
  }

  .learn-problem {
    font-size: clamp(4.8rem, 24vw, 7.2rem);
  }

  .learn-answer input {
    height: 68px;
    font-size: 2.15rem;
  }

  .learn-answer button {
    min-height: 68px;
    padding: 0 22px;
    font-size: 1.12rem;
  }

  .training-page .training-stage {
    min-height: 100svh;
    gap: 6px;
    padding: 6px;
    border: 0;
    border-radius: 0;
    box-shadow: none;
  }

  .training-page .stage-topline {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 6px;
    align-items: center;
    font-size: 0.86rem;
  }

  .training-page .stage-actions {
    display: flex;
    gap: 6px;
  }

  .training-page .stage-actions button {
    width: auto;
    min-height: 34px;
    padding: 0 10px;
    font-size: 0.86rem;
  }

  h1 {
    font-size: 2rem;
    line-height: 1.05;
  }

  .panel,
  .setup-band,
  .training-stage,
  .account-upgrade,
  .student-card,
  .table-section {
    padding: 14px;
  }

  .setup-form,
  .account-form,
  .settings-form,
  .answer-form,
  .metric-grid.compact,
  .metric-grid.mini,
  .stat-panel .metric-grid.mini {
    grid-template-columns: 1fr;
  }

  .stage-topline {
    align-items: stretch;
    flex-direction: column;
  }

  .stage-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .problem-card {
    min-height: 230px;
    padding: 16px;
  }

  .training-page .problem-card {
    min-height: calc(100svh - 58px);
    gap: 10px;
    padding: 8px;
    border: 0;
    border-radius: 0;
  }

  .problem-text {
    font-size: 3.4rem;
  }

  .training-page .problem-text {
    font-size: 4.2rem;
  }

  .training-page .answer-form {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 6px;
  }

  .training-page .answer-form input {
    height: 48px;
    font-size: 1.35rem;
  }

  .training-page .answer-form button {
    width: auto;
    min-height: 48px;
    padding: 0 14px;
  }

  button,
  .primary-button,
  .secondary-button,
  .danger-button {
    width: 100%;
  }

  .inline-form,
  .action-row {
    width: 100%;
  }
}

@media (max-width: 560px) and (max-height: 520px) {
  .auth-wrap:focus-within .auth-copy,
  .student-login:focus-within .school-badge,
  .student-login:focus-within h1 {
    display: none;
  }
}