/* ===== CHALLENGE PAGE STYLES ===== */

/* ===== HERO SECTION ===== */
.challenge-hero {
    padding-top: calc(var(--space-3xl) + 60px);
    background: var(--bg);
    color: var(--text);
    text-align: left;
  }
  
  .challenge-intro { 
    text-align: left; 
    max-width: min(100%, var(--container-max)); 
    margin: 0 auto; 
  }
  
  .challenge-intro .eyebrow {
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-size: 14px;
    font-weight: 600;
    opacity: 0.9;
    margin-bottom: var(--space-sm);
    color: var(--text-muted);
  }
  
  .challenge-intro .headline {
    margin-bottom: var(--space-lg);
    font-weight: 700;
    max-width: 800px;
    color: var(--text);
    font-size: clamp(32px, 5vw, 56px);
    line-height: 1.2;
  }
  
  .challenge-intro .subhead {
    font-size: clamp(16px, 2vw, 20px);
    line-height: 1.5;
    max-width: 600px;
    opacity: 0.95;
    color: var(--text-muted);
  }
  
  /* ===== LAYOUT ===== */
  .challenge-layout {
    display: grid;
    grid-template-columns: max-content 1fr;
    gap: clamp(24px, 3vw, 48px);
    align-items: start;
  }
  
  /* ===== SIDEBAR NAVIGATION ===== */
  .challenge-nav {
    position: sticky;
    top: calc(60px + var(--space-lg));
    align-self: start;
    display: grid;
    gap: var(--space-sm);
    justify-items: start;
  }
  
  .challenge-nav a {
    display: inline-block;
    width: auto;
    padding: var(--space-md) var(--space-lg);
    border-radius: 12px;
    border: 1px solid var(--line);
    background: var(--bg);
    color: var(--text);
    text-decoration: none;
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 15px;
    line-height: 1.2;
    letter-spacing: 0.01em;
    transition: all 0.3s ease;
    white-space: nowrap;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  }
  
  .challenge-nav a:hover,
  .challenge-nav a:focus-visible {
    background: var(--accent-light);
    border-color: #DB6AB1;
    outline: none;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
    opacity: 1;
  }
  
  .challenge-nav a.is-active {
    border-color: #DB6AB1;
    background: #DB6AB1;
    color: #fff;
    box-shadow: 0 4px 16px rgba(219, 106, 177, 0.3);
  }
  
  /* ===== CONTENT AREA ===== */
  .challenge-content { 
    display: grid; 
    gap: clamp(32px, 4vw, 64px); 
  }
  
  .prompt { 
    scroll-margin-top: calc(60px + var(--space-lg));
  }
  
  /* ===== IMAGES ===== */
  .prompt-figure { 
    margin: 0; 
  }
  
  .prompt-figure img {
    width: min(58vw, 900px);
    max-width: 100%;
    height: auto;
    display: block;
    margin-inline: 0;
    border-radius: 12px;
    box-shadow: var(--shadow);
  }
  
  /* Extra space between Sign-in errors images */
  #p5 .prompt-figure img:first-of-type {
    margin-bottom: var(--space-lg);
  }
  
  .img-credit {
    text-align: left;
    color: var(--text-muted);
    font-size: 14px;
    margin-top: var(--space-sm);
    line-height: 1.4;
  }
  
  /* ===== BACK TO TOP BUTTON ===== */
  #backToTop {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    font-size: 20px;
    cursor: pointer;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
    z-index: 999;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  
  #backToTop:hover { 
    background: color-mix(in oklab, var(--accent), white 15%);
    transform: translateY(-2px);
  }
  
  #backToTop.show { 
    opacity: 1; 
    visibility: visible; 
  }
  
  /* ===== RESPONSIVE DESIGN ===== */
  @media (max-width: 980px) {
    .challenge-layout { 
      grid-template-columns: 1fr; 
      gap: var(--space-xl);
    }
    
    .challenge-nav {
      position: static;
      grid-template-columns: repeat(3, max-content);
      gap: var(--space-sm);
      justify-content: start;
    }
    
    .prompt-figure img {
      width: min(90vw, 720px);
      margin-inline: auto;
    }
    
    .img-credit { 
      text-align: center; 
    }
  
    .challenge-hero {
      padding-top: calc(var(--space-2xl) + 60px);
    }
  }
  
  @media (max-width: 640px) {
    .challenge-nav { 
      grid-template-columns: repeat(2, max-content); 
      gap: var(--space-xs);
    }
  
    .challenge-nav a {
      padding: var(--space-xs) var(--space-sm);
      font-size: 13px;
    }
  
    .prompt-figure img {
      width: min(95vw, 600px);
    }
  
    #backToTop {
      bottom: 16px;
      right: 16px;
      width: 44px;
      height: 44px;
      font-size: 18px;
    }
  
    .challenge-content {
      gap: var(--space-xl);
    }
  }
  
  /* ===== FOCUS STYLES ===== */
  .challenge-nav a:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
  }
  
  .challenge-nav a:focus:not(:focus-visible) {
    outline: none;
  }
  
  /* ===== REDUCED MOTION ===== */
  @media (prefers-reduced-motion: reduce) {
    .challenge-nav a,
    #backToTop {
      transition: none !important;
    }
    
    .challenge-nav a:hover,
    #backToTop:hover {
      transform: none !important;
    }
  }