/* static/style.css */
:root {
  --primary: #2563eb;
  --primary-light: #dbeafe;
  --success: #16a34a;
  --success-light: #dcfce7;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --code-bg: #282a36;
  --radius: 12px;
  --font: 'Segoe UI', system-ui, sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: var(--font); font-size: 18px; line-height: 1.7; color: var(--text); background: var(--bg); }

/* Header */
.site-header { background: var(--primary); padding: 12px 24px; position: sticky; top: 0; z-index: 100; }
.site-logo { color: white; text-decoration: none; font-size: 1.2rem; font-weight: 700; }

/* Pyodide status bar */
.pyodide-status { background: var(--primary-light); text-align: center; padding: 8px; font-size: 0.9rem; }
.pyodide-status.ready { background: var(--success-light); color: var(--success); }
.progress-bar { height: 4px; background: #bfdbfe; margin-top: 4px; border-radius: 2px; overflow: hidden; }
.progress-fill { height: 100%; width: 40%; background: var(--primary); animation: pulse 1.5s ease-in-out infinite; }
@keyframes pulse { 0%,100% { width: 20%; } 50% { width: 80%; } }

/* Lesson navigation */
.lesson-nav { display: flex; align-items: center; justify-content: space-between; padding: 12px 24px; background: var(--card-bg); border-bottom: 1px solid var(--border); gap: 12px; }
.nav-btn { padding: 8px 16px; border-radius: 8px; background: var(--primary); color: white; text-decoration: none; font-size: 0.9rem; white-space: nowrap; }
.nav-btn.disabled { background: var(--border); color: var(--text-muted); pointer-events: none; }
.lesson-title-nav { font-weight: 600; text-align: center; flex: 1; }

/* Layout */
.lesson-layout { display: grid; grid-template-columns: 1fr; max-width: 1200px; margin: 0 auto; padding: 24px; gap: 24px; }
@media (min-width: 900px) { .lesson-layout { grid-template-columns: 3fr 1.5fr; } }

/* Body typography */
.lesson-body h1 { font-size: 1.8rem; margin-bottom: 16px; color: var(--primary); }
.lesson-body h2 { font-size: 1.4rem; margin: 28px 0 12px; border-left: 4px solid var(--primary); padding-left: 12px; }
.lesson-body h3 { font-size: 1.1rem; margin: 20px 0 8px; }
.lesson-body p { margin-bottom: 12px; }
.lesson-body ul, .lesson-body ol { margin: 8px 0 12px 24px; }
.lesson-body table { border-collapse: collapse; width: 100%; margin: 16px 0; font-size: 0.95rem; }
.lesson-body th, .lesson-body td { border: 1px solid var(--border); padding: 8px 12px; }
.lesson-body th { background: var(--primary-light); }
.lesson-body code { background: #f1f5f9; padding: 2px 6px; border-radius: 4px; font-family: var(--mono); font-size: 0.9em; color: #be185d; }
.lesson-body blockquote { border-left: 4px solid #fbbf24; background: #fefce8; padding: 12px 16px; margin: 16px 0; border-radius: 0 8px 8px 0; font-style: italic; }

/* Code blocks */
.code-block { margin: 20px 0; border-radius: var(--radius); overflow: hidden; border: 2px solid var(--border); }
.demo-block { border-color: #93c5fd; }
.exercise-block { border-color: #86efac; }
.code-block-header { padding: 10px 16px; font-weight: 600; font-size: 0.95rem; }
.demo-block .code-block-header { background: #dbeafe; color: #1d4ed8; }
.exercise-block .code-block-header { background: #dcfce7; color: #15803d; }
.CodeMirror { font-family: var(--mono) !important; font-size: 15px !important; height: auto !important; min-height: 60px; }
.CodeMirror-scroll { max-height: 400px; }
.code-actions { display: flex; gap: 8px; padding: 8px 12px; background: var(--code-bg); }
.run-btn { padding: 6px 16px; background: #16a34a; color: white; border: none; border-radius: 6px; cursor: pointer; font-size: 0.9rem; font-weight: 600; }
.run-btn:disabled { background: #94a3b8; cursor: not-allowed; }
.run-btn:hover:not(:disabled) { background: #15803d; }
.download-btn { padding: 6px 16px; background: #0284c7; color: white; border: none; border-radius: 6px; cursor: pointer; font-size: 0.9rem; font-weight: 600; }
.download-btn:hover { background: #0369a1; }

/* input() shim fields */
.code-block-input-area { background: #1e293b; padding: 8px 12px; }
.input-label { color: #94a3b8; font-size: 0.85rem; margin-bottom: 4px; }
.input-field { display: block; width: 100%; padding: 6px 10px; margin-bottom: 4px; background: #334155; border: 1px solid #475569; color: white; border-radius: 6px; font-family: var(--mono); font-size: 0.9rem; }

/* Output */
.output-area { background: #1e293b; padding: 10px 14px; min-height: 32px; font-family: var(--mono); font-size: 14px; color: #e2e8f0; }
.output-line { white-space: pre-wrap; line-height: 1.5; }
.output-error { color: #fca5a5; }

/* Cheatsheet */
.cheatsheet { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; height: fit-content; position: sticky; top: 80px; font-size: 0.9rem; }
.cheatsheet h3 { font-size: 1rem; margin-bottom: 10px; color: var(--primary); }
.cheatsheet-item { padding: 6px 0; border-bottom: 1px solid var(--border); color: var(--text-muted); }

/* Lesson footer */
.lesson-footer { max-width: 1200px; margin: 0 auto; padding: 16px 24px 40px; }
.complete-btn { padding: 12px 24px; background: var(--primary); color: white; border: none; border-radius: 8px; cursor: pointer; font-size: 1rem; font-weight: 600; }
.complete-btn.done { background: var(--success); }

/* Index */
.index-hero { text-align: center; padding: 48px 24px 24px; }
.index-hero h1 { font-size: 2rem; margin-bottom: 8px; color: var(--primary); }
.index-hero p { color: var(--text-muted); }
.lessons-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; max-width: 1200px; margin: 0 auto; padding: 0 24px 48px; }
.lesson-card { background: var(--card-bg); border: 2px solid var(--border); border-radius: var(--radius); padding: 20px; text-decoration: none; color: var(--text); transition: border-color 0.2s, transform 0.15s; display: block; }
.lesson-card:hover { border-color: var(--primary); transform: translateY(-2px); }
.lesson-card.completed { border-color: var(--success); background: var(--success-light); }
.lesson-num { font-size: 0.8rem; color: var(--text-muted); margin-bottom: 4px; }
.lesson-card-title { font-weight: 700; font-size: 1rem; margin-bottom: 6px; }
.lesson-card-summary { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 12px; }
.lesson-status { font-size: 0.8rem; color: var(--text-muted); }
.lesson-status.done { color: var(--success); font-weight: 600; }

/* Celebration animation */
.celebration { position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%); font-size: 3rem; animation: celebrate 2s ease-out forwards; pointer-events: none; z-index: 9999; }
@keyframes celebrate { 0% { opacity: 1; transform: translate(-50%,-50%) scale(0.5); } 60% { transform: translate(-50%,-65%) scale(1.4); } 100% { opacity: 0; transform: translate(-50%,-85%) scale(1); } }