/* Lesson & topic reading pages */

.lesson-prose {
  max-width: 42rem;
  font-size: 1.125rem;
  line-height: 1.75;
  color: var(--aeon-text);
}

.lesson-prose h2 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.5rem;
  margin: 2.5rem 0 1rem;
  color: var(--aeon-text);
}

.lesson-prose h3 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.2rem;
  margin: 1.75rem 0 0.75rem;
  color: var(--aeon-text);
}

.lesson-prose p {
  margin: 0 0 1rem;
  color: var(--aeon-muted);
}

.lesson-prose ul,
.lesson-prose ol {
  margin: 0 0 1.25rem 1.25rem;
  color: var(--aeon-muted);
}

.lesson-prose li {
  margin-bottom: 0.35rem;
}

.formula-block {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.95rem;
  color: var(--aeon-mono);
  padding: 0.75rem 1rem;
  margin: 1.25rem 0;
  border-left: 3px solid color-mix(in srgb, var(--aeon-highlight) 55%, transparent);
  background: var(--aeon-inset);
  overflow-x: auto;
}

.formula-block .katex {
  font-size: 1.05em;
}

.insight-box {
  background: color-mix(in srgb, var(--aeon-accent) 8%, var(--aeon-card));
  border-left: 3px solid var(--aeon-highlight);
  padding: 1.25rem 1.5rem;
  margin: 1.75rem 0;
  border-radius: 0 2px 2px 0;
}

.insight-box h4 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1rem;
  color: var(--aeon-text);
  margin: 0 0 0.5rem;
}

.insight-box p {
  margin: 0;
  font-size: 1.05rem;
}

.example-box {
  background: var(--aeon-card);
  border: 1px solid var(--aeon-border);
  padding: 1.5rem;
  margin: 1.75rem 0;
  border-radius: 2px;
  box-shadow: var(--aeon-shadow-sm);
}

.example-box h4 {
  font-family: 'Playfair Display', Georgia, serif;
  margin: 0 0 0.75rem;
  color: var(--aeon-accent);
}

.figure-diagram {
  margin: 1.5rem 0;
  text-align: center;
}

.figure-diagram .practice-diagram {
  margin-left: auto;
  margin-right: auto;
}

.figure-diagram svg,
.figure-diagram .practice-diagram svg {
  max-width: 100%;
  height: auto;
}

.figure-caption {
  font-size: 0.9rem;
  color: var(--aeon-muted);
  margin-top: 0.5rem;
  font-style: italic;
}

.breadcrumb {
  font-size: 0.85rem;
  color: var(--aeon-muted);
  margin: 0 0 1.5rem;
  line-height: 1.6;
  min-height: 2.56em;
}

.breadcrumb a {
  color: var(--aeon-mono);
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--aeon-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.breadcrumb__sep {
  margin: 0 0.35rem;
  opacity: 0.45;
}

.breadcrumb [aria-current="page"] {
  color: var(--aeon-text);
}

.lesson-page-header {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 2rem;
}

.lesson-page-header h1 {
  margin: 0;
  line-height: 1.12;
  min-height: 2.24em;
}

.lesson-page-header__row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  margin: 0;
  padding: 0;
}

.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--aeon-border);
  font-size: 0.95rem;
}

.lesson-nav a {
  color: var(--aeon-mono);
  text-decoration: none;
}

.lesson-nav a:hover {
  color: var(--aeon-accent);
}

.lesson-list-link {
  color: var(--aeon-text);
  text-decoration: none;
  transition: color 0.2s ease;
}

.lesson-list-link:hover {
  color: var(--aeon-accent);
}

.lesson-item--available .lesson-title {
  color: var(--aeon-text);
}

.topic-header {
  margin-bottom: 2rem;
}

.topic-header .topic-num {
  display: block;
  margin-bottom: 0.5rem;
}

/* Lesson ↔ Practice sub-navigation */
.lesson-subnav {
  display: flex;
  gap: 0;
  margin-bottom: 0;
  border: 1px solid var(--aeon-border);
  border-radius: 2px;
  overflow: hidden;
  width: fit-content;
}

.lesson-subnav__link {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.8rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.55rem 1.25rem;
  color: var(--aeon-muted);
  text-decoration: none;
  background: var(--aeon-card);
  border-right: 1px solid var(--aeon-border);
  transition: background 0.2s ease, color 0.2s ease;
}

.lesson-subnav__link:last-child {
  border-right: none;
}

.lesson-subnav__link:hover {
  color: var(--aeon-accent);
  background: var(--aeon-inset);
}

.lesson-subnav__link.is-active {
  background: var(--aeon-accent);
  color: var(--aeon-on-green);
}

.lesson-subnav__link.is-active:hover {
  color: var(--aeon-on-green);
  background: var(--aeon-accent);
}

.lesson-practice-cta {
  margin-top: 2.5rem;
  padding: 1.25rem 1.5rem;
  background: var(--aeon-card);
  border: 1px solid var(--aeon-border);
  border-radius: 2px;
}

.lesson-practice-cta p {
  margin: 0 0 1rem;
  color: var(--aeon-muted);
}

.lesson-practice-cta__link {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.85rem;
  color: var(--aeon-on-green);
  background: var(--aeon-accent);
  padding: 0.5rem 1rem;
  text-decoration: none;
  border-radius: 2px;
  display: inline-block;
  transition: background 0.2s ease;
}

.lesson-practice-cta__link:hover {
  background: var(--aeon-highlight);
}

/* Dedicated practice page */
.practice-app {
  max-width: 42rem;
}

.practice-session-head {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin-bottom: 1.25rem;
}

.practice-meta {
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--aeon-mono);
  margin: 0;
}

.practice-progress {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.practice-progress__step {
  flex: 1;
  height: 0.28rem;
  border-radius: 999px;
  background: var(--aeon-inset);
  border: 1px solid var(--aeon-border);
  transition: background 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.practice-progress__step.is-done {
  background: var(--aeon-highlight);
  border-color: var(--aeon-highlight);
}

.practice-progress__step.is-current {
  background: color-mix(in srgb, var(--aeon-highlight) 35%, var(--aeon-surface));
  border-color: var(--aeon-accent);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--aeon-accent) 25%, transparent);
}

.practice-card {
  background: var(--aeon-card);
  border: 1px solid var(--aeon-border);
  border-radius: 4px;
  overflow: hidden;
  box-shadow: var(--aeon-shadow-sm);
}

.practice-card__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.35rem;
  background: var(--aeon-surface);
  border-bottom: 1px solid var(--aeon-border);
}

.practice-card__badge {
  display: inline-flex;
  align-items: center;
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--aeon-accent);
  background: color-mix(in srgb, var(--aeon-accent) 12%, var(--aeon-card));
  border: 1px solid var(--aeon-border);
  border-radius: 999px;
  padding: 0.28rem 0.75rem;
}

.practice-card__body {
  padding: 1.35rem 1.35rem 0.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.practice-card__prompt-panel {
  padding: 1.15rem 1.2rem;
  background: color-mix(in srgb, var(--aeon-surface) 65%, var(--aeon-card));
  border: 1px solid var(--aeon-border);
  border-radius: 3px;
}

.practice-card__prompt {
  font-size: 1.12rem;
  line-height: 1.72;
  color: var(--aeon-text);
  margin: 0;
}

.practice-visual {
  margin: 0;
}

.practice-visual:not([hidden]) {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.practice-card__hint {
  font-size: 0.92rem;
  color: var(--aeon-muted);
  margin: 0;
  line-height: 1.6;
  padding: 0.85rem 1rem 0.85rem 2.65rem;
  background: color-mix(in srgb, var(--aeon-accent) 6%, var(--aeon-card));
  border: 1px solid var(--aeon-border);
  border-left: 3px solid var(--aeon-highlight);
  border-radius: 0 3px 3px 0;
  position: relative;
}

.practice-card__hint::before {
  content: 'Hint';
  position: absolute;
  left: 0.85rem;
  top: 0.85rem;
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--aeon-mono);
  opacity: 0.85;
}

.practice-card__hint[hidden] {
  display: none;
}

.practice-diagram__caption {
  font-size: 0.88rem;
  color: var(--aeon-muted);
  font-style: italic;
  text-align: center;
  margin: 0;
  line-height: 1.5;
}

.practice-answer-section {
  margin: 0;
  padding: 1.35rem 1.35rem 1.15rem;
  border-top: 1px solid var(--aeon-border);
  background: color-mix(in srgb, var(--aeon-surface) 35%, var(--aeon-card));
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.practice-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1rem;
  margin-top: 0.25rem;
  padding-top: 1.15rem;
  border-top: 1px solid var(--aeon-border);
}

.practice-toolbar .practice-submit,
.practice-toolbar .practice-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.25rem;
  white-space: nowrap;
  flex-shrink: 0;
  appearance: none;
  -webkit-appearance: none;
  line-height: 1.3;
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.85rem;
  border-radius: 2px;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.practice-toolbar .practice-submit {
  color: var(--aeon-on-green);
  background: var(--aeon-accent);
  border: 1px solid var(--aeon-accent);
  padding: 0.5rem 1.1rem;
}

.practice-toolbar .practice-submit:hover {
  background: var(--aeon-highlight);
  border-color: var(--aeon-highlight);
}

.practice-toolbar .practice-secondary {
  color: var(--aeon-mono);
  background: var(--aeon-card);
  border: 1px solid var(--aeon-border-strong);
  padding: 0.5rem 1.1rem;
}

.practice-toolbar .practice-secondary:hover {
  background: var(--aeon-inset);
  color: var(--aeon-accent);
}

.practice-toolbar button {
  appearance: none;
  -webkit-appearance: none;
}

.practice-toolbar__left,
.practice-toolbar__right {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
}

.practice-toolbar__right {
  margin-left: auto;
}

@media (max-width: 540px) {
  .practice-toolbar__left {
    width: 100%;
  }

  .practice-toolbar__right {
    width: 100%;
    justify-content: flex-end;
  }
}

.practice-diagram {
  width: 100%;
  max-width: 26rem;
  margin: 0 auto;
  text-align: center;
  padding: 0.5rem;
  background: var(--aeon-surface);
  border: 1px solid var(--aeon-border);
  border-radius: 4px;
  overflow: hidden;
}

.practice-diagram .figure-caption {
  margin-top: 0.85rem;
  margin-bottom: 0;
}

.practice-diagram svg,
.practice-diagram__svg {
  width: 100%;
  max-width: 22rem;
  height: auto;
  display: block;
  margin: 0 auto;
  border-radius: 2px;
}

.practice-diagram svg {
  --diagram-bg: #f4f6f5;
  --diagram-panel: rgba(255, 255, 255, 0.92);
  --diagram-grid-minor: rgba(46, 90, 60, 0.07);
  --diagram-grid-major: rgba(46, 90, 60, 0.16);
  --diagram-axis: rgba(46, 90, 60, 0.38);
  --diagram-stroke: #2E5A3C;
  --diagram-accent: #3A7A52;
  --diagram-label: #1A2E24;
  --diagram-mono: #2E6B48;
  --diagram-fill: rgba(46, 90, 60, 0.1);
}

[data-theme="dark"] .practice-diagram svg {
  --diagram-bg: #161b18;
  --diagram-panel: rgba(26, 34, 30, 0.94);
  --diagram-grid-minor: rgba(126, 184, 154, 0.07);
  --diagram-grid-major: rgba(126, 184, 154, 0.17);
  --diagram-axis: rgba(126, 184, 154, 0.42);
  --diagram-stroke: #7BC49A;
  --diagram-accent: #5CAD7E;
  --diagram-label: #E5EDE8;
  --diagram-mono: #9AADA3;
  --diagram-fill: rgba(74, 148, 104, 0.14);
}

.practice-solution {
  margin: 0;
  padding: 1rem 1.1rem;
  background: color-mix(in srgb, var(--aeon-accent) 6%, var(--aeon-card));
  border: 1px solid var(--aeon-border);
  border-left: 3px solid var(--aeon-highlight);
  border-radius: 0 3px 3px 0;
  font-size: 1.05rem;
  color: var(--aeon-muted);
}

.practice-solution .formula-block {
  margin-top: 0.5rem;
  margin-bottom: 0;
}

.practice-complete {
  background: var(--aeon-card);
  border: 1px solid var(--aeon-border);
  border-radius: 4px;
  padding: 2rem 1.5rem;
  text-align: center;
  box-shadow: var(--aeon-shadow-sm);
}

.practice-submit:disabled,
.practice-secondary:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.practice-field {
  margin: 0;
}

.practice-field__label {
  display: block;
  font-size: 0.8rem;
  color: var(--aeon-muted);
  margin-bottom: 0.5rem;
}

.practice-input {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.95rem;
  padding: 0.45rem 0.65rem;
  border: 1px solid var(--aeon-border-strong);
  border-radius: 3px;
  background: var(--aeon-bg);
  color: var(--aeon-text);
  width: 100%;
  max-width: 12rem;
}

.practice-input:focus {
  outline: 2px solid color-mix(in srgb, var(--aeon-accent) 45%, transparent);
  outline-offset: 1px;
}

.practice-submit {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.85rem;
  color: var(--aeon-on-green);
  background: var(--aeon-accent);
  border: none;
  padding: 0.5rem 1.1rem;
  border-radius: 2px;
  cursor: pointer;
  transition: background 0.2s ease;
}

.practice-submit:hover {
  background: var(--aeon-highlight);
}

.practice-result {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.9rem;
  margin: 0;
  min-height: 1.25rem;
}

.practice-result--correct {
  color: var(--aeon-highlight);
}

.practice-result--incorrect {
  color: #b85c5c;
}

[data-theme="dark"] .practice-result--incorrect {
  color: #e08a8a;
}

.practice-secondary {
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.85rem;
  color: var(--aeon-mono);
  background: var(--aeon-card);
  border: 1px solid rgba(46, 90, 60, 0.25);
  padding: 0.5rem 1.1rem;
  border-radius: 2px;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease;
}

.practice-secondary:hover {
  background: rgba(46, 90, 60, 0.08);
  color: var(--aeon-accent);
}

.practice-error {
  font-size: 0.85rem;
  color: #8B3A3A;
  margin-bottom: 1rem;
  padding: 0.75rem 1rem;
  background: rgba(139, 58, 58, 0.08);
  border-left: 3px solid #8B3A3A;
}

/* Practice calculator tool */
.practice-calc-tool {
  display: none;
}

.practice-calc-tool:not([hidden]) {
  display: block;
}

.practice-calc-tool.is-floating {
  position: fixed;
  z-index: 46;
  width: 17.5rem;
  max-width: calc(100vw - 1.25rem);
  box-shadow: 0 12px 40px rgba(30, 61, 40, 0.22);
  border-radius: 10px;
  overflow: hidden;
  background: var(--aeon-card);
  border: 1px solid rgba(46, 90, 60, 0.2);
}

[data-calc-open].is-active {
  background: rgba(46, 90, 60, 0.12);
  color: var(--aeon-accent);
  border-color: rgba(46, 90, 60, 0.35);
}

.practice-calc-handle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.55rem 0.7rem;
  background: linear-gradient(180deg, #3A7A52 0%, #2E5A3C 100%);
  color: var(--aeon-on-green);
  cursor: grab;
  touch-action: none;
  user-select: none;
  border: none;
  box-sizing: border-box;
}

.practice-calc-handle.is-dragging {
  cursor: grabbing;
}

.practice-calc-handle__grip {
  width: 0.45rem;
  height: 0.85rem;
  border-left: 2px dotted rgba(229, 237, 232, 0.65);
  border-right: 2px dotted rgba(229, 237, 232, 0.65);
  flex-shrink: 0;
}

.practice-calc-handle__title {
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  flex-shrink: 0;
}

.practice-calc-handle__hint {
  font-size: 0.62rem;
  opacity: 0.82;
  flex: 1;
  text-align: left;
}

.practice-calc-handle__close {
  font-size: 1.1rem;
  line-height: 1;
  opacity: 0.85;
  flex-shrink: 0;
}

.practice-calc-device {
  padding: 0.75rem;
  background: var(--aeon-surface);
}

.practice-calc-display {
  display: block;
  width: 100%;
  box-sizing: border-box;
  border: 1px solid var(--aeon-border-strong);
  border-radius: 8px;
  background: var(--aeon-card);
  color: var(--aeon-text);
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 1.2rem;
  line-height: 1.3;
  padding: 0.7rem 0.75rem;
  margin: 0 0 0.65rem;
  text-align: right;
  box-shadow: inset 0 2px 4px var(--aeon-inset);
}

.practice-calc-pad {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.5rem;
  width: 100%;
}

.practice-calc-pad > button.practice-calc-key {
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 2.65rem;
  margin: 0;
  padding: 0.35rem 0.25rem;
  border: 1px solid rgba(46, 90, 60, 0.28);
  border-radius: 8px;
  font-family: 'DejaVu Sans Mono', Consolas, Monaco, monospace;
  font-size: 0.9rem;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  user-select: none;
  appearance: none;
  -webkit-appearance: none;
  background-image: none;
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.85) inset,
    0 1px 2px rgba(46, 90, 60, 0.12);
  transition: background 0.12s ease, transform 0.08s ease, box-shadow 0.08s ease;
}

.practice-calc-pad > button.practice-calc-key:active {
  transform: translateY(1px);
  box-shadow: inset 0 1px 2px rgba(46, 90, 60, 0.14);
}

.practice-calc-pad > button.practice-calc-key--num {
  background-color: var(--aeon-card);
  color: var(--aeon-text);
}

.practice-calc-pad > button.practice-calc-key--num:hover {
  background-color: color-mix(in srgb, var(--aeon-surface) 70%, var(--aeon-card));
}

.practice-calc-pad > button.practice-calc-key--op {
  background-color: rgba(46, 90, 60, 0.12);
  color: var(--aeon-accent);
  font-size: 1.05rem;
}

.practice-calc-pad > button.practice-calc-key--op:hover {
  background-color: rgba(46, 90, 60, 0.18);
}

.practice-calc-pad > button.practice-calc-key--fn {
  background-color: rgba(46, 90, 60, 0.08);
  color: var(--aeon-mono);
  font-size: 0.68rem;
  letter-spacing: 0.01em;
}

.practice-calc-pad > button.practice-calc-key--fn:hover {
  background-color: rgba(46, 90, 60, 0.14);
}

.practice-calc-pad > button.practice-calc-key--util {
  background-color: rgba(139, 58, 58, 0.1);
  color: #6b3333;
  font-size: 0.82rem;
}

.practice-calc-pad > button.practice-calc-key--util:hover {
  background-color: rgba(139, 58, 58, 0.16);
}

.practice-calc-pad > button.practice-calc-key--equals {
  background-color: var(--aeon-accent);
  color: var(--aeon-on-green);
  border-color: var(--aeon-accent);
  font-size: 1rem;
  min-height: 2.85rem;
}

.practice-calc-pad > button.practice-calc-key--equals:hover {
  background-color: var(--aeon-highlight);
  border-color: var(--aeon-highlight);
}

@media (max-width: 540px) {
  .practice-calc-tool.is-floating {
    width: min(17.5rem, calc(100vw - 1rem));
  }

  .practice-calc-pad > button.practice-calc-key {
    min-height: 2.85rem;
  }
}