/* =========================================
   0) RESET & TOKENS
========================================= */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  /* Brand Colors (ai.levelup2pro.com) */
    --primary-color: #dc2626;
    --secondary-color: #1f2937;
    --success-color: #059669;
    --warning-color: #d97706;

  /* Surfaces & Text */
    --background-light: #f9fafb;
    --background-white: #ffffff;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --border-color: #e5e7eb;

  /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);

  /* Gradients */
    --gradient-red: linear-gradient(135deg, #dc2626 0%, #b91c1c 100%);
  --gradient-red-hover: linear-gradient(135deg, #b91c1c 0%, #991b1b 100%);
  --gradient-success: linear-gradient(135deg, #059669 0%, #047857 100%);

  /* Layout */
  --max-w: 1200px;
}

/* Typography & Body */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--background-white);
}

/* Layout Container */
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 20px; }

/* =========================================
   1) ANIMATIONS
========================================= */
@keyframes fadeInHero { from { opacity: 0; transform: translateY(30px);} to { opacity: 1; transform: translateY(0);} }
@keyframes fadeInSection { from { opacity: 0; transform: translateY(20px);} to { opacity: 1; transform: translateY(0);} }
@keyframes fadeInUp { from { opacity: 0; transform: translateY(30px);} to { opacity: 1; transform: translateY(0);} }
@keyframes pushUp { from { transform: translateY(0);} to { transform: translateY(-20px);} }
@keyframes slideInMessage { 0% { opacity: 0; transform: translateY(20px);} 100% { opacity: 1; transform: translateY(0);} }
@keyframes typingDot {
  0%, 60%, 100% { transform: scale(1); opacity: 0.5; }
  30% { transform: scale(1.2); opacity: 1; }
}

/* =========================================
   2) GLOBAL UTILITIES
========================================= */
.hidden { display: none !important; }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

.section {
    padding: 80px 0;
  opacity: 0; transform: translateY(20px);
  animation: fadeInSection 0.8s ease-out forwards;
}
.section.bg-light { background: var(--background-light); }
.section:nth-child(1){animation-delay:.1s}.section:nth-child(2){animation-delay:.2s}
.section:nth-child(3){animation-delay:.3s}.section:nth-child(4){animation-delay:.4s}
.section:nth-child(5){animation-delay:.5s}

.section-header { text-align: center; margin-bottom: 4rem; }
.section-header h2 { font-size: 2.75rem; font-weight: 800; letter-spacing: -0.025em; margin-bottom: 1rem; color: var(--text-primary); }
.section-header p { font-size: 1.125rem; color: var(--text-secondary); max-width: 600px; margin: 0 auto; }

/* Card base */
.card {
    background: var(--background-white);
  border: 1px solid var(--border-color);
    border-radius: 12px;
  box-shadow: var(--shadow-md);
    padding: 2rem;
  transition: all .3s cubic-bezier(0.4,0,0.2,1);
  opacity: 0; transform: translateY(30px); animation: fadeInUp .6s ease-out forwards;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 20px 25px -5px rgb(0 0 0 / .1), 0 10px 10px -5px rgb(0 0 0 / .04); }
/* Apply base card styling to existing components */
.requirement-card,
.video-card,
.prompt-card,
.criteria-card,
.examples-card,
.action-card,
.summary-card,
.submit-card,
.step-card {
    background: var(--background-white);
  border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
  padding: 2rem;
  transition: all .3s cubic-bezier(0.4,0,0.2,1);
}

/* Hover elevation for those cards */
.requirement-card:hover,
.video-card:hover,
.prompt-card:hover,
.criteria-card:hover,
.examples-card:hover,
.action-card:hover,
.summary-card:hover,
.submit-card:hover,
.step-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 25px -5px rgb(0 0 0 / .1), 0 10px 10px -5px rgb(0 0 0 / .04);
}
.video-card{
  padding:0px;
}

/* Mobile padding parity (matches .card rule) */
@media (max-width: 480px) {
  .requirement-card,
  .video-card,
  .prompt-card,
  .criteria-card,
  .examples-card,
  .action-card,
  .summary-card,
  .submit-card,
  .step-card {
    padding: 1.5rem;
}
  .video-card{
    padding:0px;
  }
}
/* was: .video-card.card:hover { ... } */
.video-card:hover { transform: translateY(-2px); }

/* Button base */
.btn {
  position: relative; overflow: hidden;
  display: inline-flex; align-items: center; justify-content: center; gap: .5rem;
  padding: .75rem 1.5rem; border: none; border-radius: 8px; font-weight: 500; font-size: .875rem;
  cursor: pointer; text-decoration: none; transition: all .3s ease;
}
.btn::before{
  content:''; position:absolute; top:50%; left:50%; width:0; height:0; border-radius:50%;
  background: rgb(255 255 255 / .2); transform: translate(-50%,-50%); transition: width .6s, height .6s;
}
.btn:active::before{ width:300px; height:300px; }
.btn:focus{ outline:2px solid var(--primary-color); outline-offset:2px; }

.btn-large { padding: 1rem 2rem; font-size: 1rem; }
.btn:disabled { opacity:.6; cursor:not-allowed; }

.btn-primary { background: var(--gradient-red); color: #fff; }
.btn-primary:hover { transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-secondary { background: var(--secondary-color); color: #fff; }
.btn-secondary:hover { background: #374151; }
.btn-success { background: var(--success-color); color: #fff; }
.btn-success:hover { background: #047857; }

/* =========================================
   3) NAVBAR
========================================= */
.navbar {
  position: fixed; top: 0; width: 100%; z-index: 1000;
    background: var(--background-white);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  transition: all .3s ease;
}
.navbar.scrolled { backdrop-filter: blur(10px); background: rgb(255 255 255 / .95); box-shadow: var(--shadow-md); }

.navbar .container {
  display: flex; align-items: center; justify-content: space-between; padding: 1rem 20px;
}
.nav-brand .logo { height: 40px; width: auto; }

.nav-menu { display: flex; gap: 2rem; align-items: center; }
.nav-link { color: var(--text-primary); text-decoration: none; font-weight: 500; transition: color .3s; }
.nav-link:hover { color: var(--primary-color); }

.nav-main-btn { background: var(--gradient-red); color: #fff !important; padding: .5rem 1rem; border-radius: 6px; font-weight: 600; transition: all .3s ease; border: 1px solid transparent; }
.nav-main-btn:hover { background: var(--gradient-red-hover); color:#fff !important; transform: translateY(-1px); box-shadow: var(--shadow-md); }
.nav-main-btn:active { transform: translateY(0); box-shadow: var(--shadow-sm); }
.nav-main-btn i { margin-right: .5rem; font-size: .875rem; }

/* Mobile Menu */
.mobile-menu-toggle { display: none; background: none; border: none; color: var(--text-primary); font-size: 1.5rem; cursor: pointer; padding: .5rem; }
.mobile-menu {
  display: none; position: absolute; top: 100%; left: 0; right: 0; background: var(--background-white);
  border-top: 1px solid var(--border-color); box-shadow: var(--shadow-md); padding: 1rem 0;
}
.mobile-menu.active { display: block; }
.mobile-menu .nav-link { display: block; padding: .75rem 1.5rem; border-bottom: 1px solid var(--border-color); }
.mobile-menu .nav-link:last-child { border-bottom: none; }
.mobile-menu .nav-main-btn {
  background: var(--gradient-red); color: #fff !important; margin: .5rem 1.5rem; text-align: center; border-radius: 8px; font-weight: 600;
}
.mobile-menu .nav-main-btn:hover { background: var(--gradient-red-hover); }

/* =========================================
   4) HERO
========================================= */
.hero {
  background: var(--gradient-red); color: #fff; text-align: center;
  padding: 120px 0 80px; opacity: 0; animation: fadeInHero 1s ease-out forwards;
}
.hero-title { font-size: 4rem; font-weight: 800; line-height: 1.1; letter-spacing: -0.025em; margin-bottom: 1rem; }
.hero-subtitle { font-size: 1.25rem; margin-bottom: 2rem; opacity: .95; font-weight: 400; }
.highlight { color: #fef3c7; }

.hero-actions { margin-top: 2rem; display: flex; justify-content: center; }
.btn-outline {
  background: var(--gradient-success) !important; color: #fff !important; border: 2px solid #10b981 !important;
  backdrop-filter: blur(10px); transition: all .3s ease; cursor: pointer;
}
.btn-outline:hover { background: linear-gradient(135deg,#047857 0%,#065f46 100%) !important; border-color:#059669 !important; transform: translateY(-2px); box-shadow: 0 8px 15px -3px rgb(5 150 105 / .3); }
.btn-outline:active { transform: translateY(0); box-shadow: 0 4px 6px -1px rgb(5 150 105 / .2); }
.btn-outline:focus { outline: none; box-shadow: 0 0 0 3px rgb(5 150 105 / .3); }

/* Hero progress */
.progress-overview { max-width: 400px; margin: 0 auto; }
.progress-bar { width: 100%; height: 8px; background: rgb(255 255 255 / .2); border-radius: 4px; overflow: hidden; margin-bottom: .5rem; }
.progress-fill { height: 100%; background: #fef3c7; border-radius: 4px; transition: width .5s ease; width: 0%; }
.progress-text { font-weight: 600; }

/* Hero instructions */
.hero-instructions { margin: 2rem 0; text-align: center; }
.quick-guide { font-size: 1.125rem; font-weight: 600; color: rgb(255 255 255 / .9); margin-bottom: 1rem; }
.instructions-content li { margin-bottom: .75rem; line-height: 1.6; }
.instructions-content p { color: rgb(255 255 255 / .8); font-style: italic; margin-top: 1rem; }

/* Ensure button clickable */
#resetProgressBtn { pointer-events: auto !important; user-select: none; -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; }

/* =========================================
   5) GRIDS & FEATURE CARDS
========================================= */
/* Requirements */
.requirements-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(300px,1fr)); gap: 2rem; margin-bottom: 4rem; }
.requirement-card { composes: card; } /* (note: for CSS-only projects, composes is conceptual; card class applied in HTML) */
.requirement-card { text-align: center; }
.requirement-icon {
  width: 80px; height: 80px; margin: 0 auto 1.5rem;
  background: var(--gradient-red); border-radius: 50%; display:flex; align-items:center; justify-content:center;
}
.requirement-icon i { font-size: 2rem; color: #fff; }
.requirement-card h3 { font-size: 1.5rem; font-weight: 600; margin-bottom: 1rem; color: var(--text-primary); }
.requirement-card p { color: var(--text-secondary); margin-bottom: 1.5rem; }
.requirement-status { display:flex; align-items:center; justify-content:center; gap:.5rem; font-weight:500; }
.requirement-status.pending { color: var(--text-light); }
.requirement-status.completed { color: var(--success-color); }

/* Videos */
.videos-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(450px,1fr)); gap: 2rem; margin-bottom: 3rem; }
.video-card { overflow: hidden; }
.video-card.card:hover { transform: translateY(-2px); }
.video-embed { position: relative; width: 100%; height: 250px; }
.video-embed iframe { width: 100%; height: 100%; }
.video-content { padding: 1.5rem; }
.video-content h3 { font-size: 1.25rem; font-weight: 600; margin-bottom: .5rem; color: var(--text-primary); }
.video-duration { color: var(--text-light); font-size: .875rem; margin-bottom: 1rem; display:flex; align-items:center; gap:.25rem; }
.video-description { color: var(--text-secondary); margin-bottom: 1.5rem; line-height: 1.5; }
.videos-summary { text-align: center; }
.summary-card { composes: card; max-width: 400px; margin: 0 auto; }
.summary-card h4 { font-size: 1.25rem; margin-bottom: 1rem; color: var(--text-primary); }
.summary-progress .progress-bar { background: var(--background-light); }
.summary-progress .progress-fill { background: var(--gradient-red); }

/* Tags */
.video-tags { display:flex; flex-wrap:wrap; gap:.5rem; margin-bottom:.75rem; }
.tag { display:inline-flex; align-items:center; padding:.25rem .75rem; border-radius:20px; font-size:.75rem; font-weight:500; text-transform:uppercase; letter-spacing:.025em; }
.tag-category { background: var(--gradient-red); color:#fff; }
.tag-status { background: var(--background-light); color: var(--text-secondary); border:1px solid var(--border-color); }
.tag-status.featured { background:#fef3c7; color:#92400e; border-color:#f59e0b; }
.tag-status.essential { background:#dbeafe; color:#1e40af; border-color:#3b82f6; }
.tag-status.required { background:#f3e8ff; color:#7c3aed; border-color:#8b5cf6; }
.tag-status.critical { background:#fee2e2; color:#dc2626; border-color:#ef4444; }

/* =========================================
   6) PROMPT / ASSIGNMENT
========================================= */
.prompt-container { max-width: 800px; margin: 0 auto; }
.prompt-card { composes: card; }
.prompt-header { display:flex; justify-content:space-between; align-items:center; flex-wrap:wrap; gap:1rem; }
.prompt-header h3 { font-size:1.5rem; font-weight:600; color:var(--text-primary); }
.prompt-actions { display:flex; flex-direction:row; align-items:center; gap:1.5rem; }
.ai-platforms { display:flex; align-items:center; gap:.75rem; flex-wrap:wrap; }
.ai-label { font-size:.875rem; color:var(--text-secondary); font-weight:500; }

.ai-platform-btn {
  display:inline-flex; align-items:center; gap:.5rem; padding:.5rem 1rem; border-radius:8px; text-decoration:none; font-size:.875rem; font-weight:500;
  transition: all .3s ease; border:1px solid var(--border-color); background:var(--background-white); color:var(--text-primary); box-shadow: var(--shadow-sm);
}
.ai-platform-btn:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); text-decoration:none; }
.ai-platform-btn i { font-size: 1rem; }
.ai-platform-btn span { font-size: .8rem; }
.ai-platform-btn.chatgpt:hover { background:#10a37f; color:#fff; border-color:#10a37f; }
.ai-platform-btn.gemini:hover { background:#4285f4; color:#fff; border-color:#4285f4; }
.ai-platform-btn.deepseek:hover { background:#6366f1; color:#fff; border-color:#6366f1; }

.prompt-text {
  background: var(--background-light); border:1px solid var(--border-color); border-radius:8px; padding:1.5rem;
  font-family: 'Courier New', monospace; font-size:.875rem; line-height:1.6; white-space:pre-line; color:var(--text-primary); margin:1rem 0;
}
.prompt-instructions { margin-top:2rem; padding-top:2rem; border-top:1px solid var(--border-color); }
.prompt-instructions h4 { font-size:1.125rem; font-weight:600; margin-bottom:1rem; color:var(--text-primary); }
.prompt-instructions ol { list-style-position: inside; color: var(--text-secondary); }
.prompt-instructions li { margin-bottom:.5rem; }

/* Assignment */
.assignment-grid { display:grid; grid-template-columns: repeat(auto-fit,minmax(400px,1fr)); gap:2rem; margin-bottom:3rem; }
.criteria-card, .examples-card, .action-card { composes: card; }
.criteria-header h3, .examples-card h3 { font-size:1.5rem; font-weight:600; margin-bottom:.5rem; color:var(--text-primary); }
.criteria-list { display:flex; flex-direction:column; gap:1.5rem; }
.criteria-item { display:flex; gap:1rem; align-items:flex-start; }
.criteria-icon { width:48px; height:48px; background:var(--gradient-red); border-radius:8px; display:flex; align-items:center; justify-content:center; flex-shrink:0; }
.criteria-icon i { color:#fff; font-size:1.25rem; }
.criteria-content h4 { font-size:1.125rem; font-weight:600; margin-bottom:.25rem; color:var(--text-primary); }
.criteria-content p { color:var(--text-secondary); font-size:.875rem; }

.example-tabs { display:flex; gap:.5rem; margin-bottom:1.5rem; flex-wrap:wrap; }
.tab-btn { padding:.5rem 1rem; border:1px solid var(--border-color); background:var(--background-white); border-radius:6px; cursor:pointer; transition: all .3s ease; font-size:.875rem; color:var(--text-secondary); }
.tab-btn.active, .tab-btn:hover { background: var(--primary-color); color:#fff; border-color: var(--primary-color); }
.tab-content { display:none; }
.tab-content.active { display:block; }
.tab-content ul { list-style:none; }
.tab-content li { padding:.75rem 0; border-bottom:1px solid var(--border-color); color:var(--text-secondary); position:relative; padding-left:1.5rem; }
.tab-content li:before { content:'•'; color:var(--primary-color); font-weight:bold; position:absolute; left:0; }
.tab-content li:last-child { border-bottom:none; }

.assignment-action { text-align:center; }
.action-card h3 { font-size:1.5rem; font-weight:600; margin-bottom:1rem; color:var(--text-primary); }
.action-card p { color:var(--text-secondary); margin-bottom:2rem; line-height:1.6; }
.submit-note { font-size:.875rem; color:var(--text-light); font-style:italic; margin-top:1rem; }

/* Submit form block */
.submit-container { max-width:600px; margin:0 auto; }
.submit-card { composes: card; text-align:center; }
.submit-content h3 { font-size:1.5rem; font-weight:700; color:var(--text-primary); margin-bottom:1rem; }
.submit-content p { color:var(--text-secondary); margin-bottom:2rem; line-height:1.6; }
.submit-actions { display:flex; flex-direction:column; align-items:center; gap:1rem; }

/* =========================================
   7) STEPS
========================================= */
.step-card {
  composes: card;
  position: relative; overflow: hidden; transform: translateY(30px);
}
.step-card::before { content:''; position:absolute; top:0; left:0; right:0; height:4px; background: var(--gradient-red); transition: all .3s ease; }
.step-card.active::before { box-shadow: 0 0 10px rgb(220 38 38 / .3); }
.step-card.completed::before { background: var(--gradient-success); }

.step-icon { width:60px; height:60px; background: var(--gradient-red); border-radius:12px; display:flex; align-items:center; justify-content:center; margin-bottom:1.5rem; color:#fff; font-size:1.5rem; transition: all .3s ease; }
.step-card.completed .step-icon { background: var(--gradient-success); }
.step-card h3 { font-size:1.5rem; font-weight:700; color:var(--text-primary); margin-bottom:.75rem; }
.step-card p { color:var(--text-secondary); margin-bottom:1.5rem; line-height:1.6; }

.step-status { display:inline-flex; align-items:center; gap:.5rem; padding:.5rem 1rem; background:#f3f4f6; color:#6b7280; border-radius:20px; font-size:.875rem; font-weight:500; margin-bottom:1.5rem; }
.step-status.completed { background:#d1fae5; color: var(--success-color); }
.step-status.in-progress { background:#fef3c7; color: var(--warning-color); }

.step-action-btn {
  width:100%; padding:.875rem 1.5rem; background: var(--gradient-red); color:#fff; border:none; border-radius:8px; font-weight:600; font-size:1rem;
  cursor:pointer; transition: all .3s ease; display:flex; align-items:center; justify-content:center; gap:.5rem;
}
.step-action-btn:hover:not(:disabled) { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.step-action-btn:disabled { background:#9ca3af; cursor:not-allowed; opacity:.6; }
.step-card.completed .step-action-btn { background: var(--gradient-success); }

/* Step themed backgrounds */
.step-card[data-step="1"] { background: linear-gradient(135deg, #e3f2fd 0%, #f3e5f5 100%); border-left:4px solid #2196f3; }
.step-card[data-step="2"] { background: linear-gradient(135deg, #e8f5e8 0%, #f1f8e9 100%); border-left:4px solid #4caf50; }
.step-card[data-step="3"] { background: linear-gradient(135deg, #fff3e0 0%, #fce4ec 100%); border-left:4px solid #ff9800; }

/* =========================================
   8) COMPLETION
========================================= */
.completion-section { background: var(--gradient-red); color:#fff; text-align:center; }
.completion-content { max-width:600px; margin:0 auto; }
.completion-icon {
  width:120px; height:120px; margin:0 auto 2rem;
  background: rgb(255 255 255 / .1); border:2px solid rgb(255 255 255 / .2); border-radius:50%;
  display:flex; align-items:center; justify-content:center; backdrop-filter: blur(10px);
}
.completion-icon i { font-size:3rem; color:#fef3c7; }
.completion-title { font-size:3rem; font-weight:800; margin-bottom:1rem; }
.completion-subtitle { font-size:1.5rem; margin-bottom:3rem; opacity:.95; }
.completion-stats { display:flex; justify-content:center; gap:2rem; margin-bottom:3rem; flex-wrap:wrap; }
.stat-item { display:flex; align-items:center; gap:.5rem; font-weight:500; }
.stat-item i { color:#fef3c7; font-size:1.125rem; }
.completion-next {
  background: rgb(255 255 255 / .1); border:1px solid rgb(255 255 255 / .2); border-radius:12px; padding:2rem; backdrop-filter: blur(10px);
}
.completion-next h4 { font-size:1.25rem; font-weight:600; margin-bottom:1rem; }
.completion-next p { margin-bottom:2rem; opacity:.9; }

/* =========================================
   9) FOOTER
========================================= */
.footer { background: var(--secondary-color); color:#fff; padding:4rem 0 2rem; }
.footer-content { display:grid; grid-template-columns:2fr 1fr 1fr; gap:3rem; margin-bottom:3rem; }
.footer-brand { max-width:500px; }
.footer-brand .footer-logo { height:50px; margin-bottom:1.5rem; }
.footer-brand p { opacity:.9; line-height:1.6; margin-bottom:1rem; font-size:1.125rem; font-weight:500; }
.footer-description { opacity:.8; font-size:.95rem; line-height:1.7; }
.footer-links h4, .footer-contact h4 { font-size:1.25rem; font-weight:700; margin-bottom:1.5rem; color:#fff; }
.footer-links ul { list-style:none; }
.footer-links li { margin-bottom:.75rem; }
.footer-links a { color:#fff; text-decoration:none; opacity:.8; transition: all .3s; font-size:1rem; display:inline-block; }
.footer-links a:hover { opacity:1; color: var(--primary-color); transform: translateX(4px); }
.footer-contact p { opacity:.8; margin-bottom:.75rem; display:flex; align-items:center; gap:.75rem; font-size:1rem; }
.footer-contact i { color: var(--primary-color); width:16px; text-align:center; }
.footer-bottom { text-align:center; padding-top:2rem; border-top:1px solid rgb(255 255 255 / .1); opacity:.7; font-size:.9rem; }

/* Footer Responsive */
@media (max-width: 768px) {
  .footer-content { 
    grid-template-columns: 1fr; 
    gap: 2rem; 
  }
  .footer-brand { max-width: none; }
  .footer-links ul { display: flex; flex-wrap: wrap; gap: 1.5rem; }
  .footer-links li { margin-bottom: 0; }
}

@media (max-width: 480px) {
  .footer { padding: 3rem 0 1.5rem; }
  .footer-content { gap: 1.5rem; }
  .footer-brand .footer-logo { height: 40px; }
  .footer-links ul { flex-direction: column; gap: 1rem; }
}

/* =========================================
   10) FLOATING PROGRESS BUTTON
========================================= */
.floating-progress-btn {
  position: fixed; bottom: 20px; right: 20px; width:60px; height:60px; z-index:1050;
  background: var(--gradient-red); border-radius:50%; display:flex; align-items:center; justify-content:center;
  color:#fff; font-weight:700; font-size:.875rem; border:2px solid #fff; box-shadow: var(--shadow-lg);
  cursor:pointer; transition: all .3s ease;
}
.floating-progress-btn:hover { transform: scale(1.1); box-shadow: 0 20px 25px -5px rgb(0 0 0 / .1), 0 10px 10px -5px rgb(0 0 0 / .04); }
.floating-progress-btn:active { transform: scale(.95); }
.floating-progress-btn::before{
  content:''; position:absolute; inset:-2px; background: var(--gradient-red); border-radius:50%; z-index:-1; opacity:0; transition: opacity .3s ease;
}
.floating-progress-btn:hover::before { opacity:.3; }
.floating-progress-btn.completed { background: var(--gradient-success); border-color:#10b981; transition: all .5s ease; }
.floating-progress-btn.completed:hover { transform: scale(1.1); box-shadow: 0 20px 25px -5px rgb(5 150 105 / .4), 0 10px 10px -5px rgb(5 150 105 / .1); }

/* =========================================
   11) CHAT (ChatGPT-style)
========================================= */
.chat-interface {
  max-width: 900px !important; margin: 0 auto !important; background:#fff !important;
  border-radius:12px !important; box-shadow: 0 4px 20px rgb(0 0 0 / .1) !important; overflow:hidden !important;
  transition: height 0.6s ease-out;
}

/* Hidden until .show */
.chat-message { display:flex; margin-bottom:1.5rem; opacity:0; transform: translateY(50px); height:0; overflow:hidden; transition: all .6s ease-out; }
.chat-message.show { opacity:1 !important; transform: translateY(0); height:auto; }
.chat-message.push-up { animation: pushUp .4s ease-out forwards; }

.chat-container { 
    padding:2rem; 
    display:flex; 
    flex-direction:column; 
    gap:0; 
    min-height: 90px;
    transition: height 0.6s ease-out;
}

.message-avatar {
  width:40px; height:40px; border-radius:50%;
  display:flex; align-items:center; justify-content:center; flex-shrink:0; font-size:1.1rem;
}
.message-content { flex:1; min-width:0; }
.message-bubble {
  padding:1rem 1.25rem; border-radius:18px; max-width:100%; word-wrap:break-word; position:relative;
}
.message-time { font-size:.75rem; color:#666; margin-top:.5rem; text-align:right; }

/* User message alignment */
.user-message { justify-content:flex-end; }
.user-message .message-content { order:1; max-width:70%; }
.user-message .message-avatar { order:2; margin-left:.75rem; }
.user-bubble { background: linear-gradient(135deg,#007bff 0%, #0056b3 100%); color:#fff; border-top-right-radius:4px; }
.user-message .message-time { text-align:right; }

/* AI message alignment */
.ai-message { justify-content:flex-start; }
.ai-message .message-avatar { margin-right:.75rem; }
.ai-message .message-time { text-align:left; }
.ai-message .message-avatar { background: linear-gradient(135deg,#667eea 0%, #764ba2 100%); color:#fff; }
.user-message .message-avatar { background: linear-gradient(135deg,#f093fb 0%, #f5576c 100%); color:#fff; }
.ai-bubble { background:#fff; color:#333; border:1px solid #e1e5e9; border-top-left-radius:4px; box-shadow: 0 2px 8px rgb(0 0 0 / .1); }

/* Typing indicator */
.typing-indicator {
  display:none !important; align-items:center; gap:.5rem; padding:1rem 1.25rem;
  background:#fff; border:1px solid #e1e5e9; border-radius:18px; border-bottom-left-radius:4px;
  box-shadow: 0 2px 8px rgb(0 0 0 / .1); margin-bottom:1.5rem; opacity:0; transform: translateY(10px); transition: all .3s ease-out;
}
.typing-indicator.show { display:flex; opacity:1; transform: translateY(0); }
.typing-dots { display:flex; gap:.25rem; }
.typing-dot { width:8px; height:8px; background:#666; border-radius:50%; animation: typingDot 1.4s infinite ease-in-out; }
.typing-dot:nth-child(2){animation-delay:.2s} .typing-dot:nth-child(3){animation-delay:.4s}

/* Prompt template within AI bubble */
.prompt-bubble .prompt-template {
  background:#fff; border:1px solid #e1e5e9; border-radius:8px; overflow:hidden; margin:0; box-shadow: 0 2px 8px rgb(0 0 0 / .3);
}
.prompt-header { background:#f8f9fa; padding:1rem; border-radius:8px 8px 0 0; border-bottom:1px solid #e1e5e9; display:flex; align-items:center; justify-content:space-between; }
.prompt-header h4 { margin:0; color:#333; font-size:1rem; font-weight:600; }
.copy-btn { background:#007bff; color:#fff; border:none; border-radius:6px; padding:.5rem 1rem; cursor:pointer; font-size:.875rem; display:flex; align-items:center; gap:.5rem; transition: all .2s ease; }
.copy-btn:hover { background:#0056b3; transform: translateY(-1px); }
.prompt-body {
  padding:1.5rem; background:#f8f9fa; font-family:'Monaco','Menlo','Ubuntu Mono',monospace;
  font-size:.875rem; line-height:1.6; color:#333; border-radius:0 0 8px 8px; white-space:pre-wrap; max-height:400px; overflow-y:auto;
}

/* AI platform buttons (chat variant) */
.ai-bubble .ai-platforms { display:flex; gap:.75rem; margin:1rem 0 0 0; flex-wrap:wrap; }
.ai-platform-btn.chatgpt { background: linear-gradient(135deg,#10a37f 0%, #1a7f64 100%); color:#fff; border:2px solid transparent; }
.ai-platform-btn.gemini  { background: linear-gradient(135deg,#4285f4 0%, #1a73e8 100%); color:#fff; border:2px solid transparent; }
.ai-platform-btn.deepseek{ background: linear-gradient(135deg,#6366f1 0%, #4f46e5 100%); color:#fff; border:2px solid transparent; }
.ai-platform-btn:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgb(0 0 0 / .15); }

/* Instructions block inside AI bubble */
.ai-bubble .instructions { background:#f8f9fa; border-radius:8px; padding:1.5rem; margin-top:1rem; border:1px solid #e1e5e9; }
.instructions h4 { margin:0 0 1rem 0; color:#333; font-size:1rem; }
.instructions ol { margin:0; padding-left:1.5rem; }
.instructions li { margin-bottom:.5rem; color:#555; line-height:1.5; }

/* =========================================
   12) OPTIONAL / MISC
========================================= */
.optional-help-section { position: relative; }
.optional-badge {
  display:inline-flex; align-items:center; gap:.5rem; background: linear-gradient(135deg,#3b82f6 0%, #1d4ed8 100%);
  color:#fff; padding:.5rem 1rem; border-radius:20px; font-size:.875rem; font-weight:600; margin-bottom:1.5rem; box-shadow: 0 4px 6px -1px rgb(59 130 246 / .3);
}
.optional-badge i { font-size:1rem; }

/* =========================================
   13) RESPONSIVE
========================================= */
/* ≤1200px */
@media (max-width: 1200px) {
  .container { max-width: 960px; }
  .hero-title { font-size: 3.5rem; }
  .section-header h2 { font-size: 2.5rem; }
}

/* ≤768px (tablet & below) */
@media (max-width: 768px) {
  .hero-title { font-size: 2.5rem; }
  .hero-subtitle { font-size: 1.125rem; }
  .section-header h2 { font-size: 2rem; }

  .nav-menu { display: none; }
  .mobile-menu-toggle { display: block; }
  .nav-main-btn { display: none; }

  .videos-grid, .assignment-grid { grid-template-columns: 1fr; }

  .prompt-header { flex-direction: row; align-items: stretch; }
  .prompt-actions { flex-direction: column; align-items: center; gap: 1rem; }
  .ai-platforms { justify-content: center; gap: .5rem; }
  .ai-platform-btn { flex: 1; justify-content: center; min-width: 0; }
  .ai-platform-btn span { display: none; }

  .step-card { padding: 1.5rem; }
  .step-icon { width: 50px; height: 50px; font-size: 1.25rem; }
  .step-action-btn { position: sticky; bottom: 20px; z-index: 100; box-shadow: 0 -4px 6px -1px rgb(0 0 0 / .1); }

  .chat-container { padding: 1rem; }
  .chat-message { margin-bottom: 1rem; }
  .message-avatar { width: 32px; height: 32px; font-size: .9rem; }
  .user-message .message-avatar { margin-left: .5rem; }
  .ai-message .message-avatar { margin-right: .5rem; }
  .message-bubble { padding: .75rem 1rem; font-size: .9rem; }
  .user-message .message-content { max-width: 85%; }

  .prompt-header { padding: .75rem; gap: .75rem; }
  .prompt-body { padding: 1rem; font-size: .8rem; }

  .ai-bubble .ai-platforms {
    display: grid !important; grid-template-columns: 1fr 1fr 1fr !important; gap: .5rem !important;
  }
  .ai-platform-btn { justify-content: center !important; padding:.75rem .5rem !important; font-size: .8rem !important; }
  .ai-bubble .instructions { padding: 1rem; }
}

/* ≤480px (mobile) */
@media (max-width: 480px) {
  .container { padding: 0 15px; }
  .section { padding: 60px 0; }
  .hero { padding: 100px 0 60px; }
  .hero-title { font-size: 2rem; }
  .section-header h2 { font-size: 1.75rem; }

  .card { padding: 1.5rem; }
  .floating-progress-btn { width:45px; height:45px; bottom:10px; right:10px; font-size:.7rem; }
  .btn { min-height: 44px; padding: .875rem 1.25rem; }
  .video-embed { height: 200px; }

  .chat-interface { margin: 0 -1rem; border-radius: 0; }
  .chat-message { padding: .75rem; }
  .message-avatar { width: 28px; height: 28px; margin-right: .5rem; }
  .prompt-body { padding: .75rem; font-size: .75rem; }
}

/* ≤320px (tiny) */
@media (max-width: 320px) {
  .hero-title { font-size: 1.75rem; }
  .section-header h2 { font-size: 1.5rem; }
  .floating-progress-btn { width:40px; height:40px; bottom:8px; right:8px; font-size:.65rem; }
  .video-embed { height: 180px; }
}

/* ========================================
   CRITICAL: AVATAR VISIBILITY CONTROL
   MUST BE LAST TO OVERRIDE ALL OTHER RULES
   ======================================== */
/* Hide AI message avatars initially */
.chat-message.ai-message.ai-message-content .message-avatar {
    opacity: 0 !important;
    visibility: hidden !important;
    transform: translateY(50px) !important;
}

/* Show AI message avatars only when message appears */
.chat-message.ai-message.ai-message-content.show .message-avatar {
    opacity: 1 !important;
    visibility: visible !important;
    transform: translateY(0) !important;
}

/* Typing indicator avatars always visible */
.chat-message.ai-message:not(.ai-message-content) .message-avatar {
    opacity: 1 !important;
    visibility: visible !important;
}