/* Pokémon Center — Python Crash Course
   Clean, focused UI. Calm light theme with one warm accent. */

* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --surface-2: #f5f5f7;
  --border: #e5e5ea;
  --border-strong: #d1d1d6;
  --text: #1d1d1f;
  --text-2: #6e6e73;
  --text-3: #8e8e93;
  --accent: #ef4444;       /* pokéball red */
  --accent-hover: #dc2626;
  --accent-soft: #fef2f2;
  --success: #10b981;
  --success-soft: #ecfdf5;
  --warning: #f59e0b;
  --warning-soft: #fffbeb;
  --code-bg: #1e293b;
  --code-text: #e2e8f0;
  --code-keyword: #c084fc;
  --code-string: #86efac;
  --code-comment: #64748b;
  --code-number: #fbbf24;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 16px 40px rgba(0,0,0,0.10);
  --radius: 10px;
  --radius-lg: 14px;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

.app {
  display: grid;
  grid-template-columns: 280px 1fr;
  height: 100vh;
  overflow: hidden;
}

/* ───── Sidebar ───── */
.sidebar {
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 22px 18px;
  overflow-y: auto;
}

.brand {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-bottom: 24px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--border);
}
.brand-mark {
  width: 42px; height: 42px;
  background: linear-gradient(135deg, #fbbf24 0%, #ef4444 100%);
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px;
  box-shadow: var(--shadow-sm);
}
.brand h1 { font-size: 17px; font-weight: 700; letter-spacing: -0.2px; }
.brand-sub { font-size: 12px; color: var(--text-3); margin-top: 2px; }

.lessons { display: flex; flex-direction: column; gap: 4px; }
.lesson-item {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 12px;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  color: var(--text-2);
  text-align: left;
  width: 100%;
  transition: all 0.15s;
}
.lesson-item:hover { background: var(--surface-2); color: var(--text); }
.lesson-item.active {
  background: var(--accent-soft);
  border-color: #fecaca;
  color: var(--accent);
  font-weight: 600;
}
.lesson-status {
  width: 22px; height: 22px;
  border: 1.5px solid var(--border-strong);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 11px;
  flex-shrink: 0;
  background: var(--surface);
}
.lesson-item.active .lesson-status { border-color: var(--accent); }
.lesson-item.complete .lesson-status {
  background: var(--success);
  border-color: var(--success);
  color: white;
}

.progress-card {
  margin-top: auto;
  padding: 14px;
  background: var(--surface-2);
  border-radius: var(--radius);
}
.progress-label { font-size: 11px; color: var(--text-3); text-transform: uppercase; letter-spacing: 0.5px; font-weight: 600; }
.progress-bar {
  height: 6px;
  background: var(--border);
  border-radius: 4px;
  margin: 8px 0 6px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--success), #34d399);
  border-radius: 4px;
  transition: width 0.4s;
  width: 0%;
}
.progress-text { font-size: 12px; color: var(--text-2); }

.reset-btn {
  margin-top: 10px;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-3);
  font-size: 12px;
  padding: 6px 10px;
  border-radius: 6px;
  cursor: pointer;
}
.reset-btn:hover { color: var(--accent); border-color: var(--accent); }

/* ───── Main ───── */
.main {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--bg);
}

.topbar {
  height: 56px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  flex-shrink: 0;
}
.lesson-meta { display: flex; gap: 8px; align-items: center; font-size: 13px; }
.lesson-num { font-weight: 600; color: var(--text); }
.lesson-divider { color: var(--text-3); }
.lesson-time { color: var(--text-2); }

.ghost-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 7px 12px;
  border-radius: 8px;
  font-size: 13px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.15s;
}
.ghost-btn:hover { background: var(--surface-2); border-color: var(--border-strong); }

.content-wrap {
  display: grid;
  grid-template-columns: 1fr 1fr;
  flex: 1;
  overflow: hidden;
  min-height: 0;
}

.lesson-content {
  padding: 32px 36px;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: var(--surface);
}
.lesson-content h2 {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.3px;
  margin-bottom: 6px;
}
.lesson-content .lesson-tagline {
  font-size: 14px;
  color: var(--text-2);
  margin-bottom: 22px;
}
.lesson-content h3 {
  font-size: 16px;
  font-weight: 600;
  margin: 22px 0 8px;
  letter-spacing: -0.1px;
}
.lesson-content p {
  margin-bottom: 12px;
  color: var(--text);
}
.lesson-content ul, .lesson-content ol {
  margin: 8px 0 16px 22px;
}
.lesson-content li { margin-bottom: 6px; }
.lesson-content code {
  background: var(--surface-2);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  color: var(--accent);
}
.lesson-content pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 14px 16px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 10px 0 14px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.5;
}
.lesson-content pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}
.callout {
  background: var(--warning-soft);
  border-left: 3px solid var(--warning);
  padding: 12px 14px;
  border-radius: 6px;
  margin: 14px 0;
  font-size: 14px;
}
.callout.info {
  background: #eff6ff;
  border-color: #3b82f6;
}
.callout.success {
  background: var(--success-soft);
  border-color: var(--success);
}
.task-box {
  background: var(--accent-soft);
  border: 1px solid #fecaca;
  border-radius: 10px;
  padding: 14px 16px;
  margin: 16px 0;
}
.task-box h4 {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--accent);
  margin-bottom: 6px;
}

/* ───── Workspace ───── */
.workspace {
  display: flex;
  flex-direction: column;
  background: var(--surface);
  overflow: hidden;
}
.workspace-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--surface-2);
  flex-shrink: 0;
}
.ws-tabs { display: flex; gap: 2px; }
.ws-tab {
  background: transparent;
  border: none;
  padding: 6px 12px;
  font-size: 13px;
  color: var(--text-2);
  cursor: pointer;
  border-radius: 6px;
  font-weight: 500;
}
.ws-tab.active { background: var(--surface); color: var(--text); box-shadow: var(--shadow-sm); }
.ws-actions { display: flex; gap: 6px; }
.run-btn, .check-btn {
  border: none;
  padding: 7px 14px;
  font-size: 13px;
  font-weight: 600;
  border-radius: 7px;
  cursor: pointer;
  transition: all 0.15s;
}
.run-btn { background: var(--text); color: white; }
.run-btn:hover { background: #000; }
.run-btn:disabled { background: var(--border-strong); cursor: not-allowed; }
.check-btn { background: var(--success); color: white; }
.check-btn:hover { background: #059669; }
.check-btn:disabled { opacity: 0.5; cursor: not-allowed; }

.ws-pane {
  display: none;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}
.ws-pane.active { display: flex; flex-direction: column; }

.editor-pane textarea {
  flex: 1;
  width: 100%;
  border: none;
  resize: none;
  padding: 16px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.6;
  background: var(--code-bg);
  color: var(--code-text);
  outline: none;
  tab-size: 4;
}

.output-pane pre {
  flex: 1;
  margin: 0;
  padding: 16px;
  background: #0f172a;
  color: #e2e8f0;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  line-height: 1.6;
  overflow: auto;
  white-space: pre-wrap;
  word-wrap: break-word;
}
.output-pane pre.error { color: #fca5a5; }

.hint-pane #hint {
  flex: 1;
  padding: 20px;
  overflow-y: auto;
  font-size: 14px;
}

.stdin-row {
  border-top: 1px solid var(--border);
  padding: 8px;
  background: var(--surface-2);
  flex-shrink: 0;
}
.stdin-row input {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 7px 10px;
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  background: var(--surface);
  outline: none;
}
.stdin-row input:focus { border-color: var(--accent); }

.check-result {
  padding: 0;
  flex-shrink: 0;
  font-size: 13px;
}
.check-result.show {
  padding: 12px 16px;
  border-top: 1px solid var(--border);
}
.check-result.pass { background: var(--success-soft); color: #047857; border-left: 3px solid var(--success); }
.check-result.fail { background: var(--accent-soft); color: #b91c1c; border-left: 3px solid var(--accent); }

/* ───── Nav Buttons ───── */
.nav-buttons {
  display: flex;
  justify-content: space-between;
  padding: 14px 24px;
  border-top: 1px solid var(--border);
  background: var(--surface);
  flex-shrink: 0;
}
.nav-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px 18px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s;
}
.nav-btn:hover:not(:disabled) { background: var(--surface-2); border-color: var(--border-strong); }
.nav-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.nav-btn.next {
  background: var(--text);
  color: white;
  border-color: var(--text);
}
.nav-btn.next:hover:not(:disabled) { background: #000; }

/* ───── Tutor Overlay ───── */
.tutor-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: none;
  align-items: flex-end;
  justify-content: flex-end;
  z-index: 50;
}
.tutor-overlay.show { display: flex; }
.tutor-panel {
  background: var(--surface);
  width: 420px;
  max-width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  animation: slideIn 0.25s ease-out;
}
@keyframes slideIn { from { transform: translateX(100%); } to { transform: translateX(0); } }

.tutor-header {
  padding: 18px 20px;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.tutor-header h3 { font-size: 16px; }
.tutor-sub { font-size: 12px; color: var(--text-3); margin-top: 2px; }
.tutor-close {
  background: transparent;
  border: none;
  font-size: 28px;
  color: var(--text-3);
  cursor: pointer;
  line-height: 1;
}
.tutor-close:hover { color: var(--text); }

.tutor-messages {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.tutor-msg {
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 14px;
  max-width: 90%;
  line-height: 1.5;
  white-space: pre-wrap;
  word-wrap: break-word;
}
.tutor-msg.user {
  background: var(--text);
  color: white;
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}
.tutor-msg.bot {
  background: var(--surface-2);
  color: var(--text);
  align-self: flex-start;
  border-bottom-left-radius: 4px;
}
.tutor-msg.bot code {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 1px 5px;
  border-radius: 3px;
  font-family: "SF Mono", Menlo, monospace;
  font-size: 12px;
}
.tutor-msg.bot pre {
  background: var(--code-bg);
  color: var(--code-text);
  padding: 10px 12px;
  border-radius: 6px;
  margin: 6px 0;
  overflow-x: auto;
  font-family: "SF Mono", Menlo, monospace;
  font-size: 12px;
}
.tutor-msg.thinking {
  color: var(--text-3);
  font-style: italic;
}

.tutor-input {
  padding: 12px;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 8px;
}
.tutor-input input {
  flex: 1;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 9px 12px;
  font-size: 14px;
  outline: none;
}
.tutor-input input:focus { border-color: var(--accent); }
.tutor-input button {
  background: var(--accent);
  color: white;
  border: none;
  padding: 9px 18px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}
.tutor-input button:hover { background: var(--accent-hover); }
.tutor-input button:disabled { opacity: 0.5; cursor: not-allowed; }

/* ───── Loading ───── */
.loading-overlay {
  position: fixed;
  inset: 0;
  background: rgba(255,255,255,0.95);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}
.loading-overlay.hide { display: none; }
.loading-content { text-align: center; }
.loading-spinner {
  width: 38px; height: 38px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin: 0 auto 14px;
}
@keyframes spin { to { transform: rotate(360deg); } }
.loading-content p { color: var(--text-2); font-size: 14px; }

/* ───── Mobile ───── */
@media (max-width: 920px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .content-wrap { grid-template-columns: 1fr; grid-template-rows: 1fr 1fr; }
  .lesson-content { border-right: none; border-bottom: 1px solid var(--border); padding: 20px; }
  .tutor-panel { width: 100%; }
}