:root {
  --paper: var(--md-surface);
  --white: var(--md-surface-lowest);
  --ink: var(--md-on-surface);
  --muted: var(--md-on-surface-variant);
  --line: var(--md-outline-variant);
  --page-width: 1200px;
  --model-green-container: #17231b;
  --model-green-tonal: #254130;
  --model-green-active: #79b88d;
  --model-green-ink: #b6f2c1;
  --model-lilac-container: #1b202c;
  --model-lilac-tonal: #2b354d;
  --model-lilac-active: #91a9db;
  --model-lilac-ink: #bdcdf5;
  --model-peach-container: #2a1e1b;
  --model-peach-tonal: #4b2f27;
  --model-peach-active: #e69368;
  --model-peach-ink: #f6bf93;
  --model-blue-container: #172326;
  --model-blue-tonal: #21414a;
  --model-blue-active: #66b9c3;
  --model-blue-ink: #a0eef1;
  --model-yellow-container: #292518;
  --model-yellow-tonal: #4b3d20;
  --model-yellow-active: #d2b35c;
  --model-yellow-ink: #f0d37d;
  color: var(--ink);
  background: var(--paper);
}

* { box-sizing: border-box; }
html { scroll-padding-top: 80px; }
body { margin: 0; font-size: 1rem; line-height: 1.5; -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
button, select, input { font: inherit; color: inherit; }
button, summary { cursor: pointer; }
button, input, a, summary { -webkit-tap-highlight-color: transparent; }
p, h1, h2, h3, dl, dd { margin: 0; }
:focus-visible { outline: 3px solid var(--md-primary); outline-offset: 3px; }
[hidden] { display: none !important; }
::selection { color: var(--md-on-primary-container); background: var(--md-primary-container); }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
.practice-boot { padding: 32px; text-align: center; }

.practice-topbar { position: sticky; top: 0; z-index: 3; background: var(--md-surface-low); border-bottom: 1px solid var(--line); }
.practice-topbar-inner, .practice-page {
  width: min(100%, var(--page-width)); margin-inline: auto; padding-inline: clamp(16px, 4vw, 36px);
}
.practice-topbar-inner { min-height: 64px; display: flex; align-items: center; justify-content: space-between; gap: 8px; }

.practice-page { padding-block: 28px 64px; }
.checkpoint-review a { color: var(--md-primary); text-decoration: underline; text-underline-offset: 3px; }
.practice-save-warning { position: sticky; top: 72px; z-index: 2; margin-bottom: 16px; padding: 10px 14px; border-radius: 12px; background: #332816; color: #f2bf70; }
.practice-save-warning[data-pending] { background: var(--md-secondary-container); color: var(--md-on-secondary-container); }

.practice-account-layout { display: grid; grid-template-columns: minmax(0, 512px); gap: 22px; align-items: start; }
.practice-account-layout.with-art { grid-template-columns: minmax(0, 646px) minmax(0, 512px); gap: clamp(22px, 3.06vw, 44px); }
.practice-account-card { min-width: 0; overflow-wrap: anywhere; }
.practice-account-art {
  height: 283px;
  padding: 6px;
  border: 1px solid #633d42;
  border-radius: 16px;
  background: var(--md-surface-lowest);
  box-shadow: 0 3px #211417;
}
.practice-account-art img { display: block; width: 100%; height: 100%; object-fit: cover; border-radius: 11px; }
.practice-account-name { font-size: 21px; font-weight: 700; }
@media (max-width: 760px) {
  .practice-account-layout.with-art { grid-template-columns: minmax(0, 1fr); }
  .practice-account-art { height: 124px; }
}
.practice-account-form { display: grid; gap: 8px; }
.practice-account-form label { font-weight: 700; }
.practice-account-form input { width: 100%; min-height: 48px; padding: 8px 12px; border: 1px solid var(--md-outline); border-radius: 8px; background: var(--paper); font-size: 1rem; letter-spacing: .12em; }
.practice-account-form > .practice-button { margin-top: 5px; }
.practice-account-form + .text-button { margin-top: 6px; }
.practice-account-status { color: var(--muted); font-size: .875rem; }
.practice-account-status:empty { display: none; }
.practice-account-status.practice-account-error { color: var(--bright-error); }

.practice-button {
  min-height: 48px; padding: 8px 18px; display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  border: 1px solid transparent; border-radius: 999px; background: transparent; color: var(--md-primary);
  font-size: .875rem; font-weight: 500; letter-spacing: .006em; line-height: 1.25; text-align: center;
  transition: background-color 160ms ease, color 160ms ease, box-shadow 160ms ease, transform 160ms ease;
}
.practice-button:is(.primary, .tonal, .secondary, .model-control):not(:disabled) { box-shadow: var(--md-elevation-1); }
.practice-button:is(.primary, .tonal, .secondary, .model-control):not(:disabled):is(:hover, :focus-visible):not(:active) { box-shadow: var(--md-elevation-2); }
.practice-button:active:not(:disabled) { transform: translateY(1px); }
.practice-button.primary { background: var(--md-primary); color: var(--md-on-primary); }
.practice-button.primary:hover:not(:disabled) { background: var(--md-primary-hover); }
.practice-button.tonal, .model-control:not(.secondary) { background: var(--md-secondary-container); color: var(--md-on-secondary-container); }
.practice-button.tonal:hover, .model-control:not(.secondary):hover { background: var(--md-primary-container); }
.practice-button.secondary { border-color: var(--md-outline); }
.practice-button.secondary:hover, .practice-button.text-button:hover, .practice-button.back-link:hover { background: var(--md-state-hover); }
.practice-button:disabled { color: #5f5a67; background: #e8e3ed; cursor: default; }
.practice-button.back-link { flex-direction: row-reverse; justify-content: start; padding-inline: 8px 13px; margin-inline-start: -8px; }
.practice-button .m3-icon { font-size: 20px; }
.text-button { padding-inline: 8px; }

.tone-green { --tone: var(--model-green-container); --tone-ink: var(--model-green-ink); --tone-deep: var(--model-green-tonal); }
.tone-lilac { --tone: var(--model-lilac-container); --tone-ink: var(--model-lilac-ink); --tone-deep: var(--model-lilac-tonal); }
.tone-peach { --tone: var(--model-peach-container); --tone-ink: var(--model-peach-ink); --tone-deep: var(--model-peach-tonal); }
.tone-blue { --tone: var(--model-blue-container); --tone-ink: var(--model-blue-ink); --tone-deep: var(--model-blue-tonal); }
.tone-yellow { --tone: var(--model-yellow-container); --tone-ink: var(--model-yellow-ink); --tone-deep: var(--model-yellow-tonal); }

.unit-card, .progress-panel, .checkpoint-card, .lesson-rule, .lesson-example, .model-exercise, .question-card, .lesson-complete { box-shadow: var(--md-elevation-1); }

.class-switch {
  display: inline-flex; flex-wrap: wrap; gap: 0; align-items: center; width: fit-content;
  border: 1px solid var(--md-outline); border-radius: 999px; color: var(--md-on-surface);
}
.class-switch a { min-width: 88px; min-height: 48px; display: inline-flex; align-items: center; justify-content: center; gap: 6px; padding: 4px 13px; font-size: .875rem; font-weight: 500; }
.class-switch a:first-child { border-start-start-radius: 999px; border-end-start-radius: 999px; }
.class-switch a:last-child { border-start-end-radius: 999px; border-end-end-radius: 999px; }
.class-switch a + a { border-inline-start: 1px solid var(--md-outline); }
.class-switch a:hover { background: var(--md-state-hover); }
.class-switch a[aria-current] { background: var(--md-primary); color: var(--md-on-primary); }
.class-switch .m3-icon { font-size: 17px; }

.course-layout { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 24px; align-items: start; margin-top: 34px; }
.section-heading, .panel-heading { display: flex; justify-content: space-between; gap: 12px; align-items: center; }
.section-heading { margin-bottom: 14px; }
.section-heading h2, .section-title { font-size: 1.5rem; line-height: 1.25; font-weight: 500; }
.section-heading > span { color: var(--muted); font-size: .875rem; white-space: nowrap; }
.unit-grid { display: grid; grid-template-columns: minmax(0, 1fr); gap: 10px; }
.unit-card {
  --unit-inset: 12px;
  --unit-radius: 20px;
  min-width: 0;
  border-radius: var(--unit-radius);
  background: var(--md-surface-container-low);
  overflow: hidden;
  transition: background-color 160ms ease;
}
.unit-card.unit-current { background: var(--md-primary-container); }
.unit-card:hover, .unit-card:focus-within { background: var(--md-surface-container); }
.unit-card-link {
  display: grid;
  grid-template-columns: minmax(144px, min(25%, 360px)) minmax(0, 1fr);
  align-items: center;
  gap: clamp(12px, 2vw, 24px);
  min-height: 100%;
  padding: var(--unit-inset);
  border-radius: inherit;
}
.unit-card .unit-card-link:focus-visible { outline-offset: -4px; }
.unit-card-art { overflow: hidden; border-radius: calc(var(--unit-radius) - var(--unit-inset)); }
.unit-index {
  flex: none;
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border-radius: 6px;
  background: var(--md-surface-low);
  color: var(--md-on-surface);
  font-size: .8125rem;
}
.unit-card-content { min-width: 0; padding: 6px 4px; display: grid; gap: 7px; }
.unit-card-content :is(h3, h2) { font-size: 1.16rem; line-height: 1.3; font-weight: 600; overflow-wrap: anywhere; }
.unit-card-content h3 { display: flex; align-items: center; gap: 8px; }
.unit-card-content p { max-width: 62ch; color: var(--muted); font-size: .9375rem; line-height: 1.55; }
.unit-card-bottom { min-height: 28px; display: flex; justify-content: space-between; align-items: center; color: var(--md-primary); font-size: .8125rem; font-weight: 500; }

.progress-panel, .checkpoint-card { border-radius: 12px; padding: 18px; min-width: 0; }
.progress-panel { background: var(--white); }
.panel-heading h2, .progress-grades h2 { font-size: 1.125rem; line-height: 1.3; font-weight: 500; }
.panel-heading .m3-icon { color: var(--md-primary); }
.stat-value { margin-top: 9px; color: var(--muted); font-size: .875rem; font-variant-numeric: tabular-nums; }
.stat-value strong { font-size: 1.75rem; color: var(--ink); line-height: 1.2; font-weight: 700; }
.course-meter { height: 8px; overflow: hidden; border-radius: 99px; background: var(--md-secondary-container); }
.course-meter span { height: 100%; display: block; border-radius: 99px; background: var(--md-primary); transform-origin: left; animation: meter-in 360ms cubic-bezier(.2,.8,.2,1) both; }
.progress-panel .course-meter { margin-top: 8px; }
.stat-note { color: var(--muted); font-size: .875rem; margin-top: 9px; }
.progress-panel .text-button { margin: 4px 0 -8px -8px; }
.checkpoint-card { background: var(--tone); color: var(--tone-ink); }
.checkpoint-card .panel-heading .m3-icon { color: var(--tone-ink); }
.checkpoint-card p { margin-top: 7px; font-size: .875rem; }
.checkpoint-card .practice-button { margin-top: 10px; }
.checkpoint-card .stat-note { color: var(--tone-ink); }
.progress-help { margin-top: 4px; max-width: 54ch; color: var(--muted); }
.progress-help summary { min-height: 48px; width: fit-content; padding-block: 12px; color: var(--md-primary); font-weight: 500; }
.progress-help p { padding-bottom: 6px; font-size: .9375rem; }
.progress-grades { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr)); gap: 16px; margin: 18px 0; }
.progress-unit-list { list-style: none; margin: 12px 0; padding: 0; }
.progress-unit-list li { display: flex; justify-content: space-between; align-items: center; gap: 8px; border-top: 1px solid var(--line); font-size: .875rem; }
.progress-unit-list a { display: flex; align-items: center; min-height: 48px; }
.progress-unit-list a:hover { color: var(--md-primary); text-decoration: underline; }
.progress-unit-list span { color: var(--muted); white-space: nowrap; }
@keyframes meter-in { from { transform: scaleX(.25); } to { transform: scaleX(1); } }

.page-title { font-size: 2.5rem; line-height: 1.15; letter-spacing: -.025em; font-weight: 700; overflow-wrap: anywhere; }
.page-description { margin-top: 6px; color: var(--muted); }
.unit-header { margin-top: 8px; border-radius: 20px; padding: 24px; background: var(--tone); color: var(--tone-ink); display: grid; grid-template-columns: minmax(0, 1fr) 185px; align-items: end; gap: 16px; }
.unit-header h1 { color: var(--ink); }
.unit-header p { margin-top: 6px; }
.unit-progress { font-size: .875rem; font-weight: 500; }
.unit-progress .course-meter { margin-top: 8px; background: var(--tone-deep); }
.unit-layout { margin-top: 22px; }
.unit-lessons { padding: 0; margin: 10px 0 0; list-style: none; }
.unit-lessons li + li { border-top: 1px solid var(--line); }
.unit-lessons a {
  display: grid; grid-template-columns: 44px minmax(0, 1fr) 24px; align-items: center; min-height: 72px;
  gap: 12px; padding: 8px 14px; border-radius: 12px;
}
.unit-lessons a:hover { background: var(--md-surface-container); }
.lesson-current a { background: var(--md-secondary-container); }
.lesson-index { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 50%; background: var(--md-surface-container-high); font-weight: 500; }
.lesson-current .lesson-index { background: var(--md-primary); color: var(--md-on-primary); }
.lesson-done .lesson-index { background: var(--model-green-tonal); color: var(--model-green-ink); }
.lesson-row-copy { display: grid; min-width: 0; gap: 2px; }
.lesson-row-copy strong { font-weight: 500; }
.lesson-row-copy small { color: var(--muted); font-size: .8125rem; }
.extra-grid { margin-top: 18px; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.page-title + .class-switch { margin-top: 14px; }

.lesson-page { max-width: 1120px; }
.lesson-toolbar {
  display: grid; grid-template-columns: minmax(94px, .8fr) minmax(0, 1fr) minmax(140px, .8fr); align-items: center;
  gap: 12px; margin-bottom: 19px;
}
.lesson-toolbar .back-link { justify-self: start; }
.lesson-step-number { grid-column: 3; justify-self: end; color: var(--muted); font-size: .8125rem; font-weight: 500; text-align: end; }
.lesson-heading { margin-bottom: 20px; display: flex; flex-wrap: wrap; gap: 3px 12px; align-items: center; justify-content: space-between; }
.lesson-reference { margin-top: 5px; color: var(--muted); font-size: .875rem; }
.practice-button.lesson-jump { display: none; }
.lesson-layout { display: grid; grid-template-columns: minmax(0, 1.07fr) minmax(0, .93fr); align-items: start; gap: 18px; }
.lesson-enter { animation: lesson-in 190ms cubic-bezier(.2,.8,.2,1) both; }
@keyframes lesson-in { from { transform: translateY(4px); } to { transform: translateY(0); } }
.lesson-notes { display: grid; grid-template-columns: minmax(0, 1fr); gap: 15px; min-width: 0; }
.lesson-rule, .lesson-example { border-radius: 12px; min-width: 0; padding: 19px; }
.lesson-rule { background: var(--md-surface-container-low); }
.lesson-example { background: var(--white); }
.lesson-notes h2, .model-exercise h2, .checkpoint-review h2 { font-size: 1.25rem; font-weight: 500; line-height: 1.3; }
.lesson-notes p { margin-top: 7px; }
.formula-ink {
  min-width: 0; overflow-x: auto; scrollbar-width: thin; padding: 11px 13px; margin-top: 8px; border-radius: 8px;
  background-color: #1b2130;
  background-image: linear-gradient(#b4c6ff17 1px, transparent 1px), linear-gradient(90deg, #b4c6ff17 1px, transparent 1px);
  background-size: 17px 17px;
  color: var(--ink); font: 1.28rem Kalam, Roboto, sans-serif;
}
.formula-ink .katex-display { margin: .24em 0; min-width: max-content; text-align: start; }
.formula-ink .katex-display > .katex { text-align: start; }
.worked-steps { margin: 12px 0 0; padding-inline-start: 24px; }
.worked-steps li { padding-inline-start: 4px; }
.worked-steps li + li { margin-top: 12px; }
.worked-steps li::marker { color: var(--md-primary); font-weight: 700; }
.worked-steps p { font-size: .9375rem; }
.worked-example { margin-block-start: 14px; }
.worked-example + .worked-example { border-block-start: 1px solid var(--line); padding-block-start: 16px; }
.worked-example h3 { font-size: 1.125rem; }
#lesson-model-title:focus { outline: 3px solid var(--md-primary); outline-offset: 3px; }
#lesson-model-title { scroll-margin-top: 72px; }

.model-exercise { background: var(--md-surface-container-low); border-radius: 12px; padding: 16px; min-width: 0; }
.model-instruction { margin: 7px 0 13px; color: var(--muted); }
.practice-model { min-width: 0; }
.practice-model-figure { overflow: hidden; background: var(--tone); border-radius: 12px; }
.practice-model-plot { position: relative; }
.practice-model-canvas, .practice-preview-canvas { display: block; width: 100%; height: auto; aspect-ratio: 16 / 9; }
.practice-drag-handle { position: absolute; width: 44px; height: 44px; transform: translate(-50%, -50%); cursor: grab; touch-action: none; }
.practice-drag-handle:active { cursor: grabbing; }
.practice-measurements { display: flex; flex-wrap: wrap; gap: 6px; padding-top: 10px; }
.practice-measurements > div { min-width: 0; flex: 1 1 auto; padding: 7px 10px; background: var(--tone); border-radius: 8px; }
.practice-measurements dt { color: var(--tone-ink); font-size: .8125rem; font-weight: 500; }
.practice-measurements dd { color: var(--ink); font-weight: 700; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; }
.practice-controls { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 140px), 1fr)); gap: 5px 12px; padding-top: 13px; }
.practice-control { display: grid; align-content: start; min-width: 0; font-size: .875rem; }
.control-caption { display: flex; align-items: center; justify-content: space-between; gap: 8px; min-height: 22px; font-weight: 500; }
.control-reading { color: var(--tone-ink); font-weight: 700; font-variant-numeric: tabular-nums; white-space: nowrap; }
.practice-control input { width: 100%; height: 48px; margin: 0; accent-color: var(--md-primary); }
.practice-control select { min-height: 48px; padding: 7px 9px; border: 1px solid var(--md-outline); border-radius: 8px; background: var(--white); font-size: 1rem; }
.model-actions, .lesson-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin-top: 12px; }
.model-actions { margin-top: 6px; }
.model-control { padding-inline: 13px; }
.lesson-insight { margin-top: 10px; color: var(--muted); }
.lesson-insight summary { min-height: 48px; padding: 11px 4px; font-size: .875rem; font-weight: 500; }
.lesson-insight p { margin: 0 0 6px; font-size: .875rem; }
.practical-note { border-block: 1px solid var(--line); }
.practical-note summary { color: var(--md-primary); }

.question-layout { grid-template-columns: minmax(0, 1.1fr) minmax(0, .9fr); }
.question-card { background: var(--md-surface-container-low); padding: clamp(16px, 3vw, 24px); border-radius: 12px; min-width: 0; }
.question-card h1, .lesson-complete h1 { font-size: 1.875rem; line-height: 1.2; letter-spacing: -.015em; font-weight: 700; overflow-wrap: anywhere; }
.question-aids { display: grid; gap: 10px; min-width: 0; }
.question-model { border: 1px solid var(--line); background: var(--paper); border-radius: 12px; min-width: 0; }
.question-model summary, .result-detail summary { min-height: 48px; padding: 11px 14px; font-weight: 500; }
.question-model > .practice-model, .question-model > .lesson-notes { padding: 8px 12px 12px; }
.practice-choices { min-width: 0; display: grid; gap: 8px; margin: 16px 0 0; padding: 0; border: 0; }
.practice-choice {
  position: relative; display: grid; grid-template-columns: 31px minmax(0, 1fr); align-items: center; gap: 10px; min-height: 52px;
  padding: 6px 10px; border: 1px solid var(--line); border-radius: 12px; background: var(--paper); cursor: pointer;
}
.practice-choice input { position: absolute; opacity: 0; width: 1px; height: 1px; }
.practice-choice:has(input:focus-visible) { outline: 3px solid var(--md-primary); outline-offset: 2px; }
.practice-choice:hover, .practice-choice:has(input:checked) { background: var(--md-secondary-container); border-color: var(--md-primary); }
.choice-letter { display: grid; place-items: center; min-height: 31px; border-radius: 50%; background: var(--md-surface-container-highest); font-size: .8125rem; font-weight: 700; }
.practice-choice.choice-correct { background: #203529; border-color: #5e986c; }
.practice-choice.choice-wrong { background: #3b2420; border-color: #a76659; }
.practice-feedback { margin-top: 10px; padding: 10px 13px; border-radius: 12px; }
.feedback-correct { background: #203529; color: #97e4ac; }
.feedback-wrong { background: #3b2420; color: #ff9a87; }
.lesson-complete { margin: 10px auto 0; max-width: 660px; border-radius: 20px; background: var(--md-primary-container); color: var(--md-on-primary-container); padding: 24px; }
.complete-mark { display: grid; place-items: center; width: 48px; height: 48px; margin-bottom: 10px; border-radius: 50%; background: var(--md-primary); color: var(--md-on-primary); }
.lesson-complete p { margin-top: 7px; }
.checkpoint-question, .checkpoint-review { margin: 14px auto 0; max-width: 660px; }
.checkpoint-review { display: grid; gap: 8px; }
.result-detail { border: 1px solid var(--line); border-radius: 12px; }
.result-detail p, .result-detail a { display: block; margin: 0 14px 9px; }
.score-pass, .score-miss { display: inline-block; border-radius: 999px; padding: 2px 7px; margin-inline-end: 7px; font-size: .75rem; }
.score-pass { background: #203529; color: #97e4ac; }
.score-miss { background: #3b2420; color: #ff9a87; }

@media (max-width: 950px) {
  .course-layout { grid-template-columns: minmax(0, 1fr) 245px; gap: 16px; }
}
@media (max-width: 760px) {
  .course-layout { grid-template-columns: minmax(0, 1fr); }
  .lesson-layout, .question-layout { grid-template-columns: minmax(0, 1fr); }
  .practice-button.lesson-jump { display: inline-flex; }
  .page-title { font-size: 2rem; }
}
@media (max-width: 560px) {
  .practice-page { padding-block: 16px 42px; }
  .practice-topbar-inner { min-height: 60px; }
  .course-layout { margin-top: 21px; }
  .progress-grades { grid-template-columns: minmax(0, 1fr); }
  .unit-header { grid-template-columns: minmax(0, 1fr); padding: 17px; }
  .lesson-toolbar { grid-template-columns: auto minmax(0, 1fr) minmax(92px, auto); gap: 6px; }
  .lesson-step-number { font-size: .75rem; max-width: 120px; }
  .lesson-heading { margin-bottom: 13px; }
  .lesson-rule, .lesson-example, .model-exercise { padding: 13px; }
  .question-card h1, .lesson-complete h1 { font-size: 1.5rem; }
  .formula-ink { font-size: 1.13rem; padding: 8px 9px; }
}
@media (max-width: 360px) {
  .practice-topbar-inner, .practice-page { padding-inline: 12px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}

/* Field & atlas interface */
.practice-topbar-inner { width: min(100%, 1440px); padding-inline: clamp(16px, 3vw, 32px); }
.practice-profile-link { min-height: 48px; display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding-inline: 12px; border: 1px solid var(--line); border-radius: 10px; color: var(--ink); font-size: .875rem; font-weight: 500; }
.practice-profile-link:hover { background: var(--md-state-hover); }
.practice-profile-link .m3-icon { color: var(--md-primary); }
.practice-page { width: 100%; max-width: 1224px; padding: 30px clamp(12px, 2vw, 26px) 54px; }
.practice-topbar { background: var(--md-surface-low); }
.course-layout { grid-template-columns: minmax(0, 1fr) 278px; gap: clamp(18px, 2.6vw, 32px); margin-top: 40px; }
.section-heading { padding-bottom: 12px; border-bottom: 1px solid var(--line); }
.section-heading h2 { font-size: 1.6rem; font-weight: 600; }
.progress-panel, .checkpoint-card { border: 1px solid var(--line); border-radius: 12px; padding: 17px; }
.progress-panel { background: var(--md-surface-container-low); }
.checkpoint-card { border-color: color-mix(in srgb, var(--tone-ink) 34%, transparent); }
.progress-panel .course-meter { height: 7px; }
.course-meter { background: #313b31; }
.course-meter span { background: var(--md-primary); }
.class-switch { border-color: var(--md-outline); border-radius: 9px; overflow: hidden; }
.class-switch a { min-height: 46px; }
.class-switch a[aria-current] { background: var(--md-primary); color: var(--md-on-primary); }
.practice-account-card { border: 1px solid var(--line); border-radius: 12px; background: var(--md-surface-container-low); }
.practice-account-form input, .practice-control select { background: var(--md-surface); color: var(--ink); }
.practice-button.primary { background: var(--md-primary); color: var(--md-on-primary); box-shadow: var(--md-elevation-1); }
.practice-button.primary:hover:not(:disabled) { background: var(--md-primary-hover); }
.practice-button.tonal, .model-control:not(.secondary) { background: var(--md-secondary-container); color: var(--md-on-secondary-container); }
.practice-button.secondary { border-color: var(--md-outline); color: var(--ink); }
.practice-button:disabled { color: var(--muted); background: var(--md-surface-container-high); }
.lesson-rule, .lesson-example, .model-exercise, .question-card, .lesson-complete { border: 1px solid var(--line); border-radius: 12px; }
.lesson-rule, .model-exercise, .question-card { background: var(--md-surface-container-low); }
.lesson-example { background: var(--md-surface-lowest); }
.practice-model-figure { border: 1px solid color-mix(in srgb, var(--tone-ink) 32%, transparent); }
.practice-model-canvas, .practice-preview-canvas { background: var(--tone); }
.practice-measurements > div { border: 1px solid color-mix(in srgb, var(--tone-ink) 25%, transparent); }
.practice-choice { border-radius: 9px; background: var(--md-surface); }
.practice-choice:hover, .practice-choice:has(input:checked) { background: var(--md-secondary-container); }
.practice-feedback { border: 1px solid var(--line); }
.result-detail { border-color: var(--line); }
.practice-save-warning { border: 1px solid #806236; }
.practice-save-warning[data-pending] { border-color: var(--md-outline); }
.course-catalogue-grid { display: grid; grid-template-columns: repeat(12, minmax(0, 1fr)); gap: 16px; align-items: stretch; }
.course-bento-item { min-width: 0; grid-column: span 6; display: grid; align-content: start; gap: 20px; padding: clamp(17px, 2.3vw, 26px); border: 1px solid var(--line); border-radius: 12px; background: var(--md-surface-container-low); box-shadow: var(--md-elevation-1); transition: border-color 160ms ease, box-shadow 160ms ease, background-color 160ms ease; }
.course-bento-item:hover, .course-bento-item:focus-within { border-color: var(--md-outline); box-shadow: var(--md-elevation-2); }
.course-tabs { display: flex; align-items: center; gap: 2px; max-width: 100%; margin-bottom: 22px; border-bottom: 1px solid var(--line); overflow-x: auto; scrollbar-width: none; }
.course-tabs::-webkit-scrollbar { display: none; }
.course-tab { min-height: 46px; flex: 0 0 auto; display: inline-flex; align-items: center; justify-content: center; gap: 7px; padding: 0 12px; border-bottom: 2px solid transparent; color: var(--muted); font-size: .8125rem; font-weight: 500; white-space: nowrap; }
.course-tab .m3-icon { font-size: 18px; }
.course-tab:hover { color: var(--ink); background: var(--md-state-hover); }
.course-tab[aria-current="page"] { border-color: var(--md-primary); color: var(--md-primary); font-weight: 700; }

@media (max-width: 980px) {
  .practice-page { padding: 24px clamp(16px, 4vw, 32px) 110px; }
  .practice-profile-link { padding-inline: 12px; }
}
@media (max-width: 760px) {
  .practice-page { padding-top: 18px; }
  .course-layout { grid-template-columns: minmax(0, 1fr); gap: 22px; margin-top: 30px; }
  .course-bento-item { grid-column: span 12; }
}
@media (max-width: 560px) {
  .practice-topbar-inner { min-height: 60px; padding-inline: 16px; }
  .practice-profile-link { width: 48px; padding: 0; }
  .practice-profile-link span { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; }
  .practice-page { padding: 16px 16px 102px; }
  .course-layout { margin-top: 24px; }
  .unit-card { --unit-inset: 8px; --unit-radius: 16px; }
  .unit-card-link { grid-template-columns: minmax(0, 1fr); gap: 8px; }
  .lesson-toolbar { grid-template-columns: auto minmax(0, 1fr) minmax(92px, auto); }
  .course-catalogue-grid { gap: 12px; }
  .course-bento-item { gap: 16px; padding: 16px; }
  .course-tabs { margin-bottom: 16px; }
  .course-tab { min-height: 44px; padding-inline: 9px; font-size: .75rem; }
}