:root {
  --primary-color:    #3a86ff;
  --secondary-color:  #8338ec;
  --accent-color:     #ff006e;
  --background-color: #ffffff;
  --text-color:       #333333;
  --gray-color:         #f0f0f5;
  --card-background:  rgba(255,255,255,0.05);
  --shadow:           0 4px 12px rgba(0,0,0,0.1);

  
  --beginner-color:     #3a86ff;
  --intermediate-color: #8338ec;
  --advanced-color:     #ff006e;


  
  --code-bg:   #001233;
  --code-text: #fffffe;
  --wm-col: rgba(0,0,0,.06);
}

.dark {
  --background-color: #001233;
  --gray-color:       rgba(255,255,255,0.05);
  --text-color:       #fffffe;
  --card-background:  rgba(255,255,255,0.05);
  --wm-col: rgba(255,255,255,.05);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  font-family: 'Poppins', sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background: var(--background-color);
  -webkit-user-select: none;
      -moz-user-select: none;
      -ms-user-select: none;
      user-select: none;
}

.progress-container {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 4px;
  z-index: 200;
}
.progress-bar {
  height: 4px;
  background: var(--accent-color);
  width: 0%;
  transition: width .2s;
}

   header{background:var(--background-color);padding-bottom:1rem;position:fixed;width:100%;top:0;z-index:100;transition:.3s;box-shadow:0 2px 10px rgba(0,0,0,.1)}
   header.scrolled{box-shadow:0 5px 20px rgba(0,0,0,.1)}
   header .logo{float:left;font-size:1.5rem;font-weight:700;color:var(--primary-color)}
   header nav{float:right}
   header nav ul{list-style:none;display:flex}
   header nav ul li{margin-left:2rem}
   header nav ul li a{color:var(--text-color);text-decoration:none;font-weight:600;transition:color .3s}
   header nav ul li a:hover{color:var(--primary-color)}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

.module-header {
  padding: 4rem 0;
  text-align: center;
  background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
  color: #fff;
}
.module-header .module-level {
  display: inline-block;
  font-weight: 600;
  color: #fff;
  background: var(--beginner-color);
  padding: .5rem 1rem;
  border-radius: 30px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
  margin-bottom: 1rem;
  font-size: 0.85rem;
  font-weight: 600;
}
.module-header .module-level.Intermedio {
  background: var(--intermediate-color);
}
.module-header .module-level.Avanzado {
  background: var(--advanced-color);
}
.module-header h1 {
  font-size: 2rem;
  margin-bottom: 1rem;
}
.module-header .module-description {
  max-width: 800px;
  margin: 0 auto;
  font-size: 1.1rem;
  color: rgba(255,255,255,.9);
}

   .module-content-wrapper {
    display: flex;
    gap: 2rem;
    margin-top: 3rem;
    position: relative;
}
@media (max-width: 992px) {
  .module-content-wrapper {
    flex-direction: column;
  }
}

.sidebar {
  flex: 0 0 280px;
  position: sticky;
  top: 6rem;
  height: calc(100vh - 6rem);
  overflow-y: auto;
}
.sidebar-nav {
  background: var(--card-background);
  padding: 1.5rem;
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.sidebar-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 1rem;
  padding-bottom: .5rem;
  border-bottom: 2px solid rgba(0,0,0,0.1);
}
.sidebar-nav ul {
  list-style: none;
}
.sidebar-nav li + li {
  margin-top: .75rem;
}
.sidebar-nav a {
  display: block;
  padding: .5rem 1rem;
  border-radius: 8px;
  color: var(--text-color);
  text-decoration: none;
  transition: background .2s;
}
.sidebar-nav a:hover,
.sidebar-nav a.active {
  background: var(--primary-color);
  color: #fff;
}

.main-content {
  flex: 1;
  min-width: 0;
}
.section {
  background: var(--card-background);
  padding: 2rem;
  margin-bottom: 2rem;
  border-radius: 12px;
  box-shadow: var(--shadow);
}
.section-title {
  font-size: 1.6rem;
  color: var(--text-color);
  margin-bottom: 1rem;
}
.section-subtitle {
  font-size: 1.4rem;
  color: var(--text-color);
  margin: 1.5rem 0 .75rem;
}
.section p {
  margin-bottom: 1rem;
}
.section ul,
.section ol {
  margin: 0 0 1.5rem 1.5rem;
}
.section li {
  margin-bottom: .5rem;
}

.table-of-contents {
  background: var(--gray-color);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 2rem;
  box-shadow: var(--shadow);
}
.table-of-contents-title {
  font-weight: 600;
  margin-bottom: .5rem;
}
.table-of-contents a {
  color: var(--primary-color);
  text-decoration: none;
}
.table-of-contents a:hover {
  text-decoration: underline;
}

.code-block {
  position: relative;
  background: var(--code-bg);
  color: var(--code-text);
  padding: 1.5rem;
  margin: 1.5rem 0;
  border-radius: 8px;
  overflow-x: auto;
  font-family: 'Fira Code', monospace;
}
::-webkit-scrollbar {
  width: 12px;
  height: 12px;
}

::-webkit-scrollbar-track {
  background: var(--card-background);
  border-radius: 10px;
  border: 1px solid rgba(0,0,0,0.05);
  box-shadow: inset 0 0 3px rgba(0,0,0,0.1);
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color), var(--accent-color));
  border-radius: 10px;
  border: 2px solid var(--background-color);
  box-shadow: 0 2px 6px rgba(0,0,0,0.2);
  transition: all 0.3s ease;
}

::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(135deg, var(--accent-color), var(--primary-color), var(--secondary-color));
  transform: scale(1.1);
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

::-webkit-scrollbar-thumb:active {
  background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
  transform: scale(0.95);
}

::-webkit-scrollbar-corner {
  background: var(--card-background);
  border-radius: 10px;
}

.dark ::-webkit-scrollbar-track {
  border: 1px solid rgba(255,255,255,0.1);
  box-shadow: inset 0 0 3px rgba(255,255,255,0.05);
}

* {
  scrollbar-width: thin;
  scrollbar-color: var(--primary-color) var(--card-background);
}
.code-block pre,
.code-block code {
  display: block;
  overflow-x: auto;
  white-space: pre;
}
.code-block .copy-btn {
  position: absolute;
  top: .5rem;
  right: .5rem;
  background: rgba(0,0,0,.3);
  color: #fff;
  border: none;
  padding: .25rem .5rem;
  font-size: .75rem;
  border-radius: 4px;
  cursor: pointer;
  opacity: .7;
  transition: opacity .2s;
}
.code-block .copy-btn:hover {
  opacity: 1;
}
.practice-btn {
  display: inline-block;
  background: var(--accent-color);
  color: #fff;
  padding: .75rem 1.5rem;
  border-radius: 25px;
  font-weight: 600;
  text-decoration: none;
  transition: background .3s;
}
.practice-btn:hover {
  background: var(--secondary-color);
}

.lab-preview {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--card-background);
  padding: 1rem 1.5rem;
  border-radius: 8px;
  box-shadow: var(--shadow);
  margin-bottom: 1.5rem;
}
.lab-title {
  font-weight: 600;
  margin-bottom: .5rem;
}

.alert {
  border-left: 4px solid;
  padding: 1rem 1.5rem;
  border-radius: 8px;
  margin: 1.5rem 0;
}
.alert-info    { background: rgba(58,134,255,.1); border-left-color: var(--primary-color); }
.alert-warning { background: rgba(255,0,110,.1); border-left-color: var(--accent-color); }
.alert-danger  { background: rgba(244,67,54,.1); border-left-color: var(--advanced-color); }
.alert-title   { font-weight: 600; margin-bottom: .5rem; display: flex; align-items: center; }

.reference-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.reference-list li {
  position: relative;
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}
.reference-list li:before {
  content: "•";
  position: absolute;
  left: 0;
  color: var(--primary-color);
}
.reference-list a {
  color: var(--primary-color);
  text-decoration: none;
}
.reference-list a:hover {
  text-decoration: underline;
}

.back-to-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  width: 3rem;
  height: 3rem;
  background: var(--primary-color);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s, transform .3s;
  transform: translateY(20px);
}
.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.back-to-top:hover {
  transform: translateY(-5px);
}
   footer{background:var(--background-color);color:var(--text-color);text-align:center;padding:2rem 0;margin-top:2rem}
   .footer-links{margin:1rem 0}
   .footer-links a{color:var(--text-color);text-decoration:none;font-weight:500;position:relative;padding-bottom:2px;transition:color .3s}
   .footer-links a::after{content:'';position:absolute;width:0;height:2px;bottom:0;left:0;background:var(--accent-color);transition:width .3s}
   .footer-links a:hover{color:var(--accent-color)}.footer-links a:hover::after{width:100%}
   .social-share a{display:inline-block;margin:0 .5rem;color:var(--text-color);transition:color .3s}
   .social-share a:hover{color:var(--primary-color)}
.image-container {
    margin: 2rem 0;
    text-align: center;
}

.image-container img {
    max-width: 100%;
    border-radius: 0.5rem;
    box-shadow: var(--shadow);
}

.image-caption {
    margin-top: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-color);
    font-style: italic;
}

.theme-toggle{position:fixed;bottom:20px;right:95%;background:var(--primary-color);color:#fff;border:none;border-radius:50%;width:50px;height:50px;font-size:1.5rem;cursor:pointer;transition:.3s;z-index:1000;display:flex;justify-content:center;align-items:center}
.theme-toggle:hover{transform:scale(1.1)}
.theme-toggle i{transition:opacity .3s,transform .3s}
.theme-toggle .fa-sun{position:absolute;opacity:0;transform:scale(.5)}
.dark .theme-toggle .fa-moon{opacity:0;transform:scale(.5)}
.dark .theme-toggle .fa-sun{opacity:1;transform:scale(1)}