.lean-playground-module {
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.28), rgba(255, 255, 255, 0)),
    transparent;
}

.lean-console {
  background: var(--chalk);
  color: #d8f3ff;
  padding: 0;
  overflow: hidden;
}

.lean-console-top {
  display: flex;
  gap: 8px;
  padding: var(--space-4);
  background: rgba(255, 255, 255, 0.06);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.lean-console-top span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--amber);
}

.lean-console-top span:nth-child(2) {
  background: var(--forest);
}

.lean-console-top span:nth-child(3) {
  background: var(--vermillion);
}

.lean-console pre {
  margin: 0;
  padding: var(--space-6);
  font-size: var(--text-sm);
}

.lean-playground-shell {
  margin-top: var(--space-8);
}

.lean-tabs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.lean-tab {
  border: 1px solid var(--color-accent);
  border-radius: 999px;
  background: #fff;
  color: var(--color-accent);
  padding: 0.7rem 1rem;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 800;
  cursor: pointer;
}

.lean-tab.active {
  background: var(--color-accent);
  color: #fff;
}

.lean-panel {
  min-height: 300px;
}

.playground-toolbar,
.practice-shell,
.exam-style-panel {
  background: rgba(255, 255, 255, 0.86);
  border: 1px solid rgba(23, 33, 43, 0.1);
  border-radius: 8px;
  box-shadow: 0 18px 45px rgba(23, 33, 43, 0.09);
}

.playground-toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-3);
  padding: var(--space-6);
  margin: var(--space-8) 0;
}

.playground-toolbar h3,
.playground-toolbar p,
.exam-style-header h3,
.exam-style-header p {
  margin: 0;
}

.playground-toolbar p,
.exam-style-header p {
  color: var(--color-text-secondary);
}

.playground-mode,
.playground-replay-btn,
.sa-chat-form button {
  border: 1px solid var(--color-accent);
  border-radius: 999px;
  background: #fff;
  color: var(--color-accent);
  padding: 0.62rem 1rem;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 800;
  cursor: pointer;
}

.playground-mode.active,
.playground-replay-btn,
.sa-chat-form button {
  background: var(--color-accent);
  color: #fff;
}

.playground-replay-btn {
  margin-left: auto;
}

.playground-panel[hidden] {
  display: none;
}

.worked-examples-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-5);
  margin: var(--space-8) 0;
}

.worked-example {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  opacity: 1;
  transform: none;
}

.worked-example p,
.practice-prompt p {
  color: var(--color-text-secondary);
}

.worked-example pre {
  margin-top: auto;
}

.worked-step-list {
  display: grid;
  gap: var(--space-3);
  margin: var(--space-3) 0 0;
  padding-left: var(--space-5);
}

.worked-step-list li span {
  display: block;
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
}

.practice-shell {
  display: grid;
  grid-template-columns: 290px minmax(0, 1fr);
  overflow: hidden;
  margin: var(--space-8) 0;
}

.practice-sidebar {
  padding: var(--space-6);
  border-right: 1px solid rgba(23, 33, 43, 0.1);
  background: rgba(228, 242, 247, 0.45);
}

.practice-sidebar h3 {
  margin-top: 0;
}

.exercise-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.exercise-tab {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  width: 100%;
  border: 1px solid rgba(23, 33, 43, 0.12);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: var(--space-3);
  font: inherit;
  font-weight: 700;
  line-height: 1.35;
  text-align: left;
  cursor: pointer;
}

.exercise-tab .exercise-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--color-accent-light);
  color: var(--teal);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 800;
  flex: 0 0 30px;
  margin-top: 0.05rem;
}

.exercise-tab .exercise-title {
  display: block;
  flex: 1 1 auto;
  min-width: 0;
  background: transparent;
  color: inherit;
  font-family: inherit;
  font-size: inherit;
  font-weight: inherit;
}

.exercise-tab code,
.practice-main h3 code,
.exam-question h4 code,
.worked-example h3 code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  font-weight: 800;
  white-space: nowrap;
  font-variant-numeric: slashed-zero;
}

.exercise-tab.active {
  border-color: var(--color-accent);
  box-shadow: inset 4px 0 0 var(--color-accent);
}

.practice-main {
  padding: var(--space-6);
  min-width: 0;
}

.lean-editor-label {
  display: block;
  margin: var(--space-5) 0 var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 800;
  color: var(--teal);
  text-transform: uppercase;
}

.lean-editor {
  width: 100%;
  min-height: 260px;
  border: 1px solid rgba(23, 33, 43, 0.16);
  border-radius: 8px;
  background: var(--chalk);
  color: #d8f3ff;
  padding: var(--space-5);
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: 1.7;
  resize: vertical;
}

.lean-editor-small {
  min-height: 140px;
}

.lean-editor:focus {
  outline: 3px solid rgba(90, 157, 184, 0.36);
  outline-offset: 2px;
}

.practice-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.practice-actions .btn:disabled {
  opacity: 0.62;
  cursor: wait;
}

.practice-feedback {
  display: none;
  margin-top: var(--space-4);
  border-radius: 8px;
  padding: var(--space-4);
  border: 1px solid rgba(23, 33, 43, 0.12);
  background: #fff;
}

.practice-feedback.show {
  display: block;
}

.practice-feedback.success {
  border-color: rgba(45, 139, 85, 0.32);
  background: var(--color-success-light);
}

.practice-feedback.error {
  border-color: rgba(201, 59, 59, 0.28);
  background: var(--color-error-light);
}

.practice-feedback.waiting {
  border-color: rgba(212, 168, 67, 0.42);
  background: rgba(212, 168, 67, 0.14);
}

.practice-feedback details {
  margin-top: var(--space-3);
}

.exam-style-panel {
  padding: var(--space-6);
  margin: var(--space-8) 0;
}

.analysis-panel {
  margin: var(--space-8) 0;
}

.analysis-summary-grid,
.analysis-mistake-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: var(--space-4);
  margin: var(--space-5) 0;
}

.analysis-stat {
  border: 1px solid rgba(23, 33, 43, 0.1);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.88);
  padding: var(--space-5);
  box-shadow: 0 12px 32px rgba(23, 33, 43, 0.07);
}

.analysis-stat strong {
  display: block;
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  line-height: 1;
  color: var(--color-accent);
}

.analysis-stat span {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
}

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

.analysis-mistake-card {
  display: grid;
  gap: var(--space-3);
}

.exam-style-header {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: var(--space-5);
  margin-bottom: var(--space-5);
}

.exam-timer {
  min-width: 92px;
  border-radius: 999px;
  background: var(--chalk);
  color: #d8f3ff;
  padding: 0.55rem 0.8rem;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 800;
  text-align: center;
}

.exam-question-section {
  margin-top: var(--space-6);
}

.exam-section-heading {
  border-top: 1px solid rgba(23, 33, 43, 0.1);
  padding-top: var(--space-5);
}

.exam-section-heading h4 {
  margin: 0;
}

.exam-section-heading p {
  max-width: 820px;
  margin: var(--space-1) 0 0;
  color: var(--color-text-secondary);
}

.exam-question {
  border-top: 1px solid rgba(23, 33, 43, 0.1);
  padding-top: var(--space-5);
  margin-top: var(--space-5);
}

.exam-question p {
  color: var(--color-text-secondary);
}

.exam-done {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-3);
  font-weight: 700;
}

.sa-chat {
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 1100;
  font-family: var(--font-body);
}

.sa-chat-toggle {
  width: 58px;
  height: 58px;
  border: 1px solid rgba(23, 33, 43, 0.18);
  border-radius: 50%;
  background: #fff;
  color: #fff;
  box-shadow: 0 14px 30px rgba(23, 33, 43, 0.22);
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 800;
  cursor: pointer;
  padding: 0;
  overflow: hidden;
}

.sa-chat-toggle img {
  display: block;
  width: 100%;
  height: 100%;
}

.sa-chat-panel {
  position: absolute;
  right: 0;
  bottom: 66px;
  width: min(430px, calc(100vw - 32px));
  max-height: min(720px, calc(100vh - 96px));
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid rgba(23, 33, 43, 0.14);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 18px 50px rgba(23, 33, 43, 0.2);
}

.sa-chat-panel[hidden] {
  display: none;
}

.sa-chat-header {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--chalk);
  color: #d8f3ff;
}

.sa-chat-header img {
  flex: 0 0 auto;
}

.sa-chat-header button {
  margin-left: auto;
}

.sa-chat-header span {
  display: block;
  font-size: var(--text-xs);
  color: rgba(216, 243, 255, 0.74);
}

.sa-chat-close {
  display: inline-grid;
  place-items: center;
  width: 30px;
  height: 30px;
  padding: 0;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 50%;
  background: transparent;
  color: #d8f3ff;
  font: 700 0.95rem/1 var(--font-body);
  cursor: pointer;
}

.sa-chat-log {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-height: 160px;
  max-height: 360px;
  overflow-y: auto;
  padding: var(--space-4);
}

.sa-quick-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4) 0;
}

.sa-quick-actions button {
  border: 1px solid rgba(23, 33, 43, 0.12);
  border-radius: 999px;
  background: #fff;
  color: var(--color-accent);
  padding: 0.4rem 0.58rem;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 800;
  cursor: pointer;
}

.sa-message {
  display: grid;
  gap: var(--space-1);
  border-radius: 8px;
  padding: var(--space-3);
  font-size: var(--text-sm);
  line-height: 1.45;
  overflow-wrap: anywhere;
}

.sa-message-assistant {
  background: var(--color-accent-light);
}

.sa-message-user {
  margin-left: var(--space-8);
  background: rgba(23, 33, 43, 0.07);
}

.sa-message-body p {
  margin: 0 0 var(--space-2);
}

.sa-message-body p:last-child,
.sa-message-body ul:last-child {
  margin-bottom: 0;
}

.sa-message-body ul {
  margin: 0 0 var(--space-2);
  padding-left: 1.15rem;
}

.sa-message-body li {
  margin: 0.25rem 0;
}

.sa-message-body code {
  font-family: var(--font-mono);
  font-size: 0.92em;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(23, 33, 43, 0.08);
  border-radius: 5px;
  padding: 0.05rem 0.28rem;
}

.sa-source {
  display: inline;
  font-weight: 800;
  color: var(--teal);
}

.sa-chat-form {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: var(--space-2);
  padding: var(--space-4);
  border-top: 1px solid rgba(23, 33, 43, 0.1);
}

.sa-chat-form input {
  min-width: 0;
  border: 1px solid rgba(23, 33, 43, 0.16);
  border-radius: 999px;
  padding: 0.65rem 0.8rem;
  font: inherit;
}

.playground-onboarding {
  position: fixed;
  inset: 0;
  z-index: 1200;
  display: grid;
  place-items: center;
  padding: var(--space-5);
  background: rgba(17, 32, 42, 0.46);
}

.playground-onboarding-card {
  position: relative;
  width: min(520px, 100%);
  border-radius: 8px;
  background: #fff;
  padding: var(--space-8);
  box-shadow: 0 24px 70px rgba(17, 32, 42, 0.26);
}

.playground-onboarding-card h2 {
  margin: var(--space-2) 0 var(--space-4);
  font-family: var(--font-display);
  color: var(--ink);
}

.playground-onboarding-card > .translation-label {
  top: var(--space-5);
  right: 4.5rem;
}

.playground-onboarding-card ol {
  margin: 0 0 var(--space-5);
  padding-left: var(--space-6);
}

.playground-onboarding-close {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  padding: 0;
  border: 1px solid rgba(23, 33, 43, 0.14);
  border-radius: 50%;
  background: #fff;
  color: var(--ink);
  font: 700 0.95rem/1 var(--font-body);
  cursor: pointer;
}

@media (max-width: 900px) {
  .worked-examples-grid,
  .practice-shell,
  .analysis-summary-grid,
  .analysis-mistake-grid {
    grid-template-columns: 1fr;
  }

  .practice-sidebar {
    border-right: 0;
    border-bottom: 1px solid rgba(23, 33, 43, 0.1);
  }
}

@media (max-width: 600px) {
  .playground-toolbar,
  .exam-style-header {
    align-items: stretch;
    flex-direction: column;
  }

  .practice-main,
  .practice-sidebar,
  .exam-style-panel,
  .playground-toolbar {
    padding: var(--space-5);
  }

  .sa-chat {
    right: 12px;
    bottom: 12px;
  }
}