@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Plus+Jakarta+Sans:wght@500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: rgba(37, 99, 235, 0.08);
  --secondary: #10b981;
  --secondary-hover: #059669;
  --secondary-light: rgba(16, 185, 129, 0.08);
  --accent: #f59e0b;
  --accent-light: rgba(245, 158, 11, 0.1);
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-hover: #f1f5f9;
  --text: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --danger: #ef4444;
  --danger-light: rgba(239, 68, 68, 0.08);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.05), 0 1px 2px -1px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.04), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-heading: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Global Reset & Base */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  color: var(--text);
  background-color: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--primary-hover);
}

/* Topbar Sticky Header */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.topbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 22px;
  letter-spacing: -0.5px;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand img {
  height: 38px;
  width: auto;
  object-fit: contain;
  transition: var(--transition);
}

.brand img:hover {
  opacity: 0.9;
}

.nav {
  display: flex;
  gap: 8px;
  align-items: center;
}

.main-nav {
  margin-left: auto;
}

.hamburger-menu {
  position: relative;
}

.hamburger-menu summary {
  width: 44px;
  height: 44px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text-secondary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  list-style: none;
  transition: var(--transition);
}

.hamburger-menu summary::-webkit-details-marker {
  display: none;
}

.hamburger-menu summary:hover {
  background: var(--bg);
  color: var(--text);
  border-color: var(--text-muted);
}

.hamburger-panel {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  width: 280px;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  background: var(--surface);
  box-shadow: var(--shadow-lg);
  z-index: 1000;
}

.hamburger-panel a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 12px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 700;
}

.hamburger-panel a:hover,
.hamburger-panel a.active {
  background: var(--primary-light);
  color: var(--primary);
}

.hamburger-panel a.danger-link {
  color: var(--danger);
}

.hamburger-panel a.danger-link:hover {
  background: var(--danger-light);
  color: var(--danger);
}

.hamburger-panel .material-symbols-outlined {
  font-size: 19px;
}

.hamburger-user {
  padding: 10px 12px 12px;
  margin-bottom: 6px;
  border-bottom: 1px solid var(--border);
}

.hamburger-user strong,
.hamburger-user span {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.hamburger-user strong {
  font-size: 14px;
  color: var(--text);
}

.hamburger-user span {
  font-size: 12px;
  color: var(--text-muted);
}

/* Navigation Links & Buttons */
.nav a, .button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 600;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background-color: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
  white-space: nowrap;
  transition: var(--transition);
}

.nav a:hover, .button:hover {
  background-color: var(--bg);
  color: var(--text);
  border-color: var(--text-muted);
}

.button.primary, .nav a.active {
  background-color: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.15);
}

.button.primary:hover, .nav a.active:hover {
  background-color: var(--primary-hover);
  border-color: var(--primary-hover);
  color: #ffffff;
  box-shadow: 0 4px 6px rgba(37, 99, 235, 0.25);
}

.button.secondary {
  background-color: var(--secondary);
  border-color: var(--secondary);
  color: #ffffff;
  box-shadow: 0 2px 4px rgba(16, 185, 129, 0.15);
}

.button.secondary:hover {
  background-color: var(--secondary-hover);
  border-color: var(--secondary-hover);
  color: #ffffff;
  box-shadow: 0 4px 6px rgba(16, 185, 129, 0.25);
}

.button.danger {
  background-color: var(--danger);
  border-color: var(--danger);
  color: #ffffff;
}

.button.danger:hover {
  background-color: #dc2626;
  border-color: #dc2626;
  box-shadow: 0 4px 6px rgba(239, 68, 68, 0.2);
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 36px 24px 100px;
}

.site-footer {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px 28px;
  color: var(--text-muted);
  font-size: 13px;
  text-align: center;
}

.protected-content main,
.protected-content .bottom-nav,
.protected-content .topbar {
  -webkit-user-drag: none;
}

.protected-content main {
  -webkit-touch-callout: none;
}

.protected-content main :not(input):not(textarea):not(select) {
  user-select: none;
  -webkit-user-select: none;
}

.screen-watermark {
  position: fixed;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(180px, 1fr));
  gap: 44px 28px;
  align-content: center;
  padding: 48px 20px;
  pointer-events: none;
  z-index: 900;
  overflow: hidden;
}

.screen-watermark span {
  color: rgba(15, 23, 42, 0.065);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-align: center;
  text-transform: uppercase;
  transform: rotate(-24deg);
  white-space: nowrap;
  transition: color 0.18s ease, font-size 0.18s ease;
}

.watermark-prominent .screen-watermark span {
  color: rgba(15, 23, 42, 0.32);
  font-size: 15px;
}

/* Modern Hero Section */
.hero {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.05) 0%, rgba(16, 185, 129, 0.05) 100%);
  border: 1px solid var(--border);
  padding: 48px;
  border-radius: var(--radius-lg);
  margin-bottom: 32px;
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: '';
  position: absolute;
  top: -50px;
  right: -50px;
  width: 200px;
  height: 200px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.08) 0%, transparent 70%);
  border-radius: 50%;
}

.hero h1 {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 40px;
  letter-spacing: -1px;
  line-height: 1.2;
  margin-bottom: 16px;
  color: var(--text);
}

.hero p {
  max-width: 780px;
  color: var(--text-secondary);
  font-size: 18px;
  line-height: 1.6;
  margin-bottom: 24px;
}

.hero .button {
  margin-right: 12px;
}

/* Grid Layout */
.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
  margin-top: 24px;
}

/* Cards & Styling */
.card {
  grid-column: span 4;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: #cbd5e1;
}

.card.wide {
  grid-column: span 8;
}

.card.full {
  grid-column: 1 / -1;
}

.card h2 {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text);
  letter-spacing: -0.5px;
}

.card h3 {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

.muted {
  color: var(--text-muted);
  font-size: 15px;
}

.stat {
  font-family: var(--font-heading);
  font-size: 36px;
  font-weight: 800;
  color: var(--primary);
  margin: 10px 0;
  line-height: 1;
}

/* Progress Bars */
.progress {
  height: 8px;
  background-color: #f1f5f9;
  border-radius: 999px;
  overflow: hidden;
  margin-top: 12px;
}

.progress span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: 999px;
  transition: width 0.5s ease-out;
}

/* Form Styles */
.form {
  max-width: 520px;
  margin: 40px auto;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 36px;
  box-shadow: var(--shadow-lg);
}

.form h1 {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 28px;
  margin-bottom: 24px;
  letter-spacing: -0.5px;
}

label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  margin: 18px 0 6px;
}

input, select, textarea {
  width: 100%;
  min-height: 44px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  font-family: var(--font-sans);
  font-size: 15px;
  color: var(--text);
  background-color: #f8fafc;
  transition: var(--transition);
}

input:focus, select:focus, textarea:focus {
  outline: none;
  background-color: var(--surface);
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

textarea {
  min-height: 120px;
  resize: vertical;
}

/* Flash alerts */
.flash {
  padding: 18px 22px;
  border-radius: var(--radius-md);
  margin-bottom: 28px;
  font-size: 18px;
  font-weight: 800;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  border: 2px solid rgba(16, 185, 129, 0.3);
  border-left: 8px solid var(--secondary);
  background-color: #ecfdf5;
  color: #065f46;
  box-shadow: var(--shadow-md);
  line-height: 1.45;
}

.flash .material-symbols-outlined {
  flex: 0 0 auto;
  margin-top: 2px;
}

.flash.error {
  font-size: 16px;
  font-weight: 700;
  border: 1px solid rgba(239, 68, 68, 0.25);
  border-left-color: var(--danger);
  background-color: var(--danger-light);
  color: var(--danger);
}

.flash.warning {
  font-size: 16px;
  font-weight: 700;
  border: 1px solid rgba(245, 158, 11, 0.25);
  border-left-color: var(--accent);
  background-color: var(--accent-light);
  color: var(--accent);
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: 999px;
  background-color: #f1f5f9;
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.25px;
  text-transform: uppercase;
}

.badge.success {
  background-color: #ecfdf5;
  color: #065f46;
}

.badge.primary {
  background-color: #eff6ff;
  color: #1e40af;
}

/* Unit and Learning Screens Layout */
.unit-tabs {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.unit-tabs .button {
  padding: 8px 16px;
  font-weight: 600;
}

.learn-layout {
  display: grid;
  grid-template-columns: 350px minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.lesson-list {
  grid-column: auto;
  max-height: calc(100vh - 140px);
  overflow-y: auto;
  position: sticky;
  top: 96px;
}

.topic-list {
  list-style: none;
  margin-top: 16px;
}

.topic-list li {
  padding: 12px 8px;
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.topic-list li:hover {
  background-color: var(--bg);
}

.topic-link {
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 15px;
  line-height: 1.4;
}

.topic-list li.selected-topic {
  background-color: var(--primary-light);
  border-bottom-color: transparent;
}

.topic-list li.selected-topic .topic-link {
  color: var(--primary);
}

.topic-list form {
  align-self: flex-start;
}

.topic-list li .button {
  padding: 4px 10px;
  min-height: 28px;
  font-size: 12px;
}

/* Lesson Reader styled as premium documentation */
.lesson-reader {
  grid-column: auto;
  line-height: 1.7;
}

.lesson-reader h2 {
  font-size: 32px;
  margin-bottom: 12px;
}

.lesson-reader h3 {
  font-size: 20px;
  margin-top: 24px;
  margin-bottom: 10px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 4px;
}

.lesson-reader p {
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-size: 16px;
}

/* Monospace containers */
pre {
  margin: 16px 0;
  padding: 16px;
  border-radius: var(--radius-sm);
  background-color: #0f172a;
  color: #f8fafc;
  font-family: var(--font-mono);
  font-size: 14px;
  overflow-x: auto;
  border: 1px solid #1e293b;
  box-shadow: inset 0 2px 4px rgba(0,0,0,0.1);
}

code {
  font-family: var(--font-mono);
  font-weight: 500;
}

.lesson-reader pre code {
  color: #38bdf8; /* Vibrant light blue */
}

/* Notebook styling for practice code exercises */
.notebook {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.notebook-cell {
  border-left: 4px solid var(--primary);
}

.code-cell {
  margin: 12px 0;
  min-height: 180px;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  background-color: #0f172a;
  color: #f8fafc;
  border: 1px solid #1e293b;
  border-radius: var(--radius-sm);
  padding: 16px;
}

.code-cell:focus {
  background-color: #020617;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
}

.cell-output {
  margin-top: 12px;
  border: 1px solid var(--border);
  background-color: #0f172a;
  color: #34d399; /* soft terminal green */
  border-radius: var(--radius-sm);
  padding: 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  min-height: 60px;
  box-shadow: var(--shadow-sm);
}

/* MCQ Interactive Selections */
.mcq-option {
  display: flex;
  align-items: center;
  position: relative;
  cursor: pointer;
  padding: 16px 20px;
  margin-bottom: 12px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-weight: 500;
  transition: var(--transition);
}

.mcq-option:hover {
  background-color: var(--bg);
  border-color: var(--text-muted);
}

.mcq-option input[type="radio"] {
  width: 20px;
  height: 20px;
  margin-right: 14px;
  accent-color: var(--primary);
}

.mcq-option:has(input[type="radio"]:checked) {
  border-color: var(--primary);
  background-color: var(--primary-light);
}

/* Bottom Nav (Mobile UI) */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid var(--border);
  box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.05);
  display: none;
  z-index: 999;
}

.bottom-nav a {
  flex: 1;
  text-align: center;
  padding: 14px 4px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.bottom-nav a.active {
  color: var(--primary);
}

/* Adaptive Breakpoints */
@media (max-width: 900px) {
  .learn-layout {
    grid-template-columns: minmax(0, 1fr);
  }
  
  .lesson-list {
    position: static;
    max-height: none;
    order: 2;
  }

  .lesson-reader {
    order: 1;
    margin-bottom: 32px;
  }
}

@media (max-width: 820px) {
  body {
    background-color: var(--surface);
  }

  h1 {
    font-size: 28px;
  }

  .topbar-inner {
    padding: 14px 20px;
    gap: 10px;
  }

  .main-nav {
    display: none;
  }

  .hamburger-panel {
    position: fixed;
    top: 70px;
    left: 16px;
    right: 16px;
    width: auto;
  }

  .bottom-nav {
    display: flex;
  }

  .container {
    padding: 24px 20px 90px;
  }

  .card, .card.wide {
    grid-column: 1 / -1;
  }

  .hero {
    padding: 32px;
  }

  .hero h1 {
    font-size: 32px;
  }
}

@media (max-width: 480px) {
  .brand {
    font-size: 19px;
  }
  
  .hero {
    padding: 24px 16px;
    border-radius: var(--radius-md);
  }

  .hero h1 {
    font-size: 26px;
  }

  .form {
    padding: 24px 16px;
    border: none;
    box-shadow: none;
  }
}

.mobile-logout {
  display: none;
}

@media (max-width: 820px) {
  .mobile-logout {
    display: inline-flex !important;
  }
}

@media print {
  .protected-content .topbar,
  .protected-content .container,
  .protected-content .bottom-nav,
  .protected-content .site-footer,
  .protected-content .screen-watermark {
    display: none !important;
  }

  .protected-content::before {
    content: "Protected PyPharm content";
    display: block;
    padding: 48px;
    font-family: Arial, sans-serif;
    font-size: 18px;
    color: #111827;
  }
}