/**
 * VPR 7 Class - Theory Page Styles
 * Стили для теоретических страниц
 */

@import url("vpr7-main.css");

/* Base Reset and Body Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
  min-height: 100vh;
  padding: 20px;
}

h1 {
  text-align: center;
  color: white;
  margin-bottom: 20px;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
  font-size: 2rem;
}

.container {
  margin: 0 auto;
}

/* Theory Container */
.container {
  max-width: 1200px;
}

/* Navigation Links */
.nav-links {
  display: flex;
  gap: 15px;
  margin-bottom: 25px;
  flex-wrap: wrap;
}

/* Theory Intro */
.theory-intro {
  background: rgba(255, 255, 255, 0.95);
  border-radius: 15px;
  padding: 25px;
  margin-bottom: 25px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.theory-intro h2 {
  color: #333;
  margin-bottom: 15px;
  font-size: 1.4rem;
}

.theory-intro p {
  color: #555;
  line-height: 1.7;
  margin-bottom: 10px;
}

/* Category Section */
.category-section {
  background: rgba(255, 255, 255, 0.95);
  border-radius: 15px;
  padding: 25px;
  margin-bottom: 25px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.category-header {
  display: flex;
  align-items: center;
  gap: 15px;
  margin-bottom: 20px;
  padding-bottom: 15px;
  border-bottom: 3px solid;
}

.category-header.input {
  border-color: #4facfe;
}

.category-header.output {
  border-color: #38ef7d;
}

.category-header.storage {
  border-color: #f093fb;
}

.category-header.processing {
  border-color: #ff6b6b;
}

.category-icon {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
}

.category-icon.input {
  background: linear-gradient(145deg, #4facfe 0%, #00f2fe 100%);
}

.category-icon.output {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.category-icon.storage {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.category-icon.processing {
  background: linear-gradient(145deg, #eb3349 0%, #f45c43 100%);
}

.category-title {
  font-size: 1.5rem;
  color: #333;
}

.category-description {
  color: #666;
  line-height: 1.6;
  margin-bottom: 20px;
  padding: 15px;
  background: #f8f9fa;
  border-radius: 10px;
  border-left: 4px solid #667eea;
}

/* Devices Grid */
.devices-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 15px;
}

/* Device Card */
.device-card {
  background: linear-gradient(145deg, #f5f7fa 0%, #e4e8eb 100%);
  border-radius: 12px;
  padding: 15px;
  cursor: pointer;
  transition: all 0.3s;
  border: 2px solid transparent;
  position: relative;
  overflow: hidden;
}

.device-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.device-card.active {
  border-color: #667eea;
  background: white;
}

.device-image {
  width: 100%;
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
  background: white;
  border-radius: 10px;
  overflow: hidden;
}

.device-image img {
  max-width: 90%;
  max-height: 70px;
  object-fit: contain;
}

.device-image svg {
  width: 60px;
  height: 60px;
}

.device-name {
  font-weight: 600;
  color: #333;
  text-align: center;
  font-size: 0.95rem;
}

/* Device Detail Modal */
.device-detail {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.device-detail.show {
  display: flex;
}

.device-detail-content {
  background: white;
  border-radius: 20px;
  padding: 30px;
  max-width: 500px;
  width: 100%;
  position: relative;
  animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.device-detail-close {
  position: absolute;
  top: 15px;
  right: 15px;
  width: 35px;
  height: 35px;
  border-radius: 50%;
  border: none;
  background: #f0f0f0;
  font-size: 1.2rem;
  cursor: pointer;
  transition: background 0.3s;
}

.device-detail-close:hover {
  background: #e0e0e0;
}

.device-detail-image {
  width: 150px;
  height: 150px;
  margin: 0 auto 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(145deg, #f5f7fa 0%, #e4e8eb 100%);
  border-radius: 15px;
  overflow: hidden;
}

.device-detail-image img {
  max-width: 90%;
  max-height: 130px;
  object-fit: contain;
}

.device-detail-image svg {
  width: 100px;
  height: 100px;
}

.device-detail-name {
  font-size: 1.4rem;
  font-weight: bold;
  color: #333;
  text-align: center;
  margin-bottom: 15px;
}

.device-detail-category {
  text-align: center;
  margin-bottom: 15px;
}

.device-detail-category span {
  display: inline-block;
  padding: 6px 15px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
  color: white;
}

.device-detail-category span.input {
  background: linear-gradient(145deg, #4facfe 0%, #00f2fe 100%);
}

.device-detail-category span.output {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.device-detail-category span.storage {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.device-detail-category span.processing {
  background: linear-gradient(145deg, #eb3349 0%, #f45c43 100%);
}

.device-detail-description {
  color: #555;
  line-height: 1.7;
  text-align: center;
}

/* Filter Buttons */
.filter-buttons {
  display: flex;
  gap: 10px;
  margin-bottom: 25px;
  flex-wrap: wrap;
  justify-content: center;
}

.filter-btn {
  padding: 10px 20px;
  border: none;
  border-radius: 25px;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.3s;
  font-weight: 500;
  background: rgba(255, 255, 255, 0.3);
  color: white;
}

.filter-btn:hover,
.filter-btn.active {
  background: white;
  color: #667eea;
}

/* Quick Navigation */
.quick-nav {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 100;
}

.quick-nav-btn {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  transition: transform 0.3s;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.quick-nav-btn:hover {
  transform: scale(1.1);
}

.quick-nav-btn.top {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
  color: white;
}

.quick-nav-btn.practice {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
  color: white;
}

/* Footer */
.footer {
  text-align: center;
  padding: 20px;
  color: rgba(255, 255, 255, 0.8);
  margin-top: 20px;
}

/* Responsive */
@media (max-width: 600px) {
  h1 {
    font-size: 1.5rem;
  }

  .devices-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .device-image {
    height: 60px;
    font-size: 2.5rem;
  }

  .category-header {
    flex-direction: column;
    text-align: center;
  }

  .quick-nav {
    bottom: 15px;
    right: 15px;
  }

  .quick-nav-btn {
    width: 45px;
    height: 45px;
  }
}

/* Formula Grid */
.formula-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin: 20px 0;
}

.formula-item {
  background: #f8f9fa;
  border-radius: 10px;
  padding: 20px;
  text-align: center;
  border: 2px solid #e0e0e0;
  transition:
    border-color 0.3s,
    transform 0.3s;
}

.formula-item:hover {
  border-color: #2a5298;
  transform: translateY(-3px);
}

.formula-item .formula-name {
  font-size: 0.9rem;
  color: #666;
  margin-bottom: 10px;
}

.formula-item .formula-expression {
  font-size: 1.2rem;
  font-family: "Courier New", monospace;
  color: #1e3c72;
  font-weight: bold;
}

.formula-item .formula-desc {
  font-size: 0.85rem;
  color: #888;
  margin-top: 10px;
}

/* Formula Box */
.formula-box {
  background: #f0f4f8;
  border: 2px solid #1e3c72;
  border-radius: 15px;
  padding: 25px;
  margin-bottom: 20px;
  text-align: center;
}

.formula-box h3 {
  margin-bottom: 15px;
  font-size: 1.2rem;
}

.formula {
  font-family: "Courier New", monospace;
  font-size: 1.3rem;
  color: #1e3c72;
  font-weight: bold;
  padding: 15px;
  background: rgba(30, 60, 114, 0.1);
  border-radius: 10px;
  text-align: center;
  line-height: 2;
}

.formula-label {
  font-size: 0.9rem;
  color: #666;
  margin-top: 10px;
}

/* Path Parts */
.path-part {
  display: inline;
}

.path-part.disk {
  color: #ffc107;
  font-weight: bold;
}

.path-part.separator {
  color: rgba(255, 255, 255, 0.7);
}

.path-part.folder {
  color: #81d4fa;
}

.path-part.file {
  color: #a5d6a7;
}

/* Path Example */
.path-example {
  background: #f8f9fa;
  border-radius: 10px;
  padding: 20px;
  margin: 15px 0;
  font-family: Consolas, Monaco, monospace;
  font-size: 1.1rem;
  line-height: 2;
  border-left: 4px solid #667eea;
}

.path-example .path-part.disk {
  color: #e94560;
  font-weight: bold;
}

.path-example .path-part.separator {
  color: #666;
}

.path-example .path-part.folder {
  color: #4facfe;
}

.path-example .path-part.file {
  color: #11998e;
}

/* Comparison Table */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.comparison-table thead {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
  color: white;
}

.comparison-table th,
.comparison-table td {
  padding: 15px;
  text-align: left;
  border-bottom: 1px solid #e9ecef;
}

.comparison-table tbody tr:last-child td {
  border-bottom: none;
}

.comparison-table tbody tr:hover {
  background: #f8f9fa;
}

.comparison-table code {
  background: #e9ecef;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.9rem;
}

/* Example Card */
.example-card {
  background: #f8f9fa;
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 20px;
  border-left: 4px solid #667eea;
}

.example-card h4 {
  color: #333;
  margin-bottom: 15px;
  font-size: 1.1rem;
}

.example-task {
  background: white;
  padding: 15px;
  border-radius: 8px;
  margin-bottom: 15px;
  border: 1px solid #e9ecef;
}

.example-solution {
  background: white;
  padding: 15px;
  border-radius: 8px;
  border: 1px solid #e9ecef;
}

/* Success Box */
.success-box {
  background: linear-gradient(145deg, #d4edda 0%, #c3e6cb 100%);
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
  border-left: 4px solid #28a745;
}

.success-box h4 {
  color: #155724;
  margin-bottom: 15px;
}

.success-box ul,
.success-box ol {
  color: #155724;
  line-height: 1.8;
  margin-left: 20px;
}

/* Warning Box */
.warning-box {
  background: linear-gradient(145deg, #fff3cd 0%, #ffeeba 100%);
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
  border-left: 4px solid #ffc107;
}

.warning-box h4 {
  color: #856404;
  margin-bottom: 15px;
}

.warning-box ul {
  color: #856404;
  line-height: 1.8;
  margin-left: 20px;
}

/* Step List */
.step-list {
  counter-reset: step-counter;
  list-style: none;
  padding-left: 0;
}

.step-list li {
  counter-increment: step-counter;
  padding: 10px 0 10px 50px;
  position: relative;
  line-height: 1.6;
}

.step-list li::before {
  content: counter(step-counter);
  position: absolute;
  left: 0;
  top: 8px;
  width: 32px;
  height: 32px;
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: bold;
  font-size: 0.9rem;
}

/* Interactive Diagram */
.interactive-diagram {
  background: #f8f9fa;
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
}

.tree-structure {
  font-family: Consolas, Monaco, monospace;
  font-size: 0.95rem;
  line-height: 1.8;
  background: white;
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
}

.tree-item {
  cursor: pointer;
  padding: 2px 5px;
  border-radius: 4px;
  transition: background 0.2s;
}

.tree-item:hover {
  background: rgba(102, 126, 234, 0.1);
}

.tree-item.disk {
  color: #e94560;
  font-weight: bold;
}

.tree-item.folder {
  color: #4facfe;
}

.tree-item.file {
  color: #11998e;
}

/* Extensions Grid */
.extensions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
  margin-bottom: 20px;
}

.extension-item {
  background: linear-gradient(145deg, #f5f7fa 0%, #e4e8eb 100%);
  border-radius: 10px;
  padding: 15px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  border: 2px solid transparent;
}

.extension-item:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  border-color: #667eea;
}

.ext-name {
  display: block;
  font-family: Consolas, Monaco, monospace;
  font-size: 1.1rem;
  font-weight: bold;
  color: #333;
  margin-bottom: 5px;
}

.ext-desc {
  display: block;
  font-size: 0.8rem;
  color: #666;
}

/* Programs Section */
.programs-section {
  background: #f8f9fa;
  border-radius: 10px;
  padding: 15px;
  margin-top: 15px;
}

.programs-section h4 {
  margin-bottom: 12px;
  color: #333;
}

.programs-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.program-badge {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
}

/* Tip Box */
.tip-box {
  background: linear-gradient(145deg, #e8f4fd 0%, #d1ecf1 100%);
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
  border-left: 4px solid #17a2b8;
}

.tip-box h4 {
  color: #0c5460;
  margin-bottom: 15px;
}

.tip-box ul {
  color: #0c5460;
  line-height: 1.8;
  margin-left: 20px;
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal.show {
  display: flex;
}

.modal-content {
  background: white;
  border-radius: 20px;
  padding: 30px;
  max-width: 500px;
  width: 100%;
  max-height: 80vh;
  overflow-y: auto;
  position: relative;
  animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.modal-close {
  position: absolute;
  top: 15px;
  right: 15px;
  width: 35px;
  height: 35px;
  border-radius: 50%;
  border: none;
  background: #f0f0f0;
  font-size: 1.2rem;
  cursor: pointer;
  transition: background 0.3s;
}

.modal-close:hover {
  background: #e0e0e0;
}

.modal-title {
  font-size: 1.3rem;
  color: #333;
  margin-bottom: 20px;
  padding-right: 30px;
}

.modal-body {
  color: #555;
  line-height: 1.7;
}

.modal-body h5 {
  color: #333;
  margin: 15px 0 10px;
  font-size: 1rem;
}

.modal-body ul {
  margin-left: 20px;
  line-height: 1.8;
}

/* Category Headers for Theory 2 & 3 */
.category-header.structure,
.category-header.navigation,
.category-header.examples,
.category-header.tips,
.category-header.text,
.category-header.presentation,
.category-header.table,
.category-header.image,
.category-header.audio,
.category-header.video,
.category-header.archive,
.category-header.web,
.category-header.executable {
  border-color: #667eea;
}

.category-icon.structure,
.category-icon.navigation,
.category-icon.examples,
.category-icon.tips,
.category-icon.text,
.category-icon.presentation,
.category-icon.table,
.category-icon.image,
.category-icon.audio,
.category-icon.video,
.category-icon.archive,
.category-icon.web,
.category-icon.executable {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

/* Fade In Animation */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Color Table */
.color-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.color-table th,
.color-table td {
  border: 2px solid #e0e0e0;
  padding: 12px 15px;
  text-align: center;
}

.color-table th {
  background: linear-gradient(145deg, #e53935 0%, #ff6f00 100%);
  color: white;
  font-weight: 600;
}

.color-table td {
  font-size: 1rem;
}

/* Color Cell */
.color-cell {
  width: 40px;
  height: 30px;
  border-radius: 5px;
  display: inline-block;
  border: 2px solid #333;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

/* Color Mixer Demo */
.color-mixer-demo {
  background: linear-gradient(145deg, #f5f7fa 0%, #e4e8eb 100%);
  border-radius: 15px;
  padding: 25px;
  margin: 20px 0;
  border: 2px solid #e0e0e0;
}

.mixer-display {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 30px;
  margin-bottom: 25px;
  flex-wrap: wrap;
}

.mixer-color-box {
  width: 120px;
  height: 120px;
  border-radius: 15px;
  border: 4px solid #333;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.mixer-sliders {
  display: flex;
  flex-direction: column;
  gap: 15px;
  max-width: 450px;
  margin: 0 auto;
}

.slider-group {
  display: flex;
  align-items: center;
  gap: 10px;
}

.slider-label {
  width: 100px;
  font-weight: bold;
  font-size: 0.95rem;
}

.slider-label.red {
  color: #e53935;
}

.slider-label.green {
  color: #43a047;
}

.slider-label.blue {
  color: #1e88e5;
}

.slider-input {
  flex: 1;
  height: 10px;
  -webkit-appearance: none;
  appearance: none;
  border-radius: 5px;
  outline: none;
}

.slider-input.red {
  background: linear-gradient(to right, #000, #ff0000);
}

.slider-input.green {
  background: linear-gradient(to right, #000, #00ff00);
}

.slider-input.blue {
  background: linear-gradient(to right, #000, #0000ff);
}

.slider-input::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: white;
  border: 3px solid #333;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.slider-input::-moz-range-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: white;
  border: 3px solid #333;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.slider-value {
  width: 50px;
  text-align: center;
  font-weight: bold;
  font-size: 1rem;
  font-family: "Courier New", monospace;
}

.mixer-info {
  text-align: center;
  margin-top: 20px;
  padding: 15px;
  background: white;
  border-radius: 10px;
}

.mixer-info .rgb-value {
  font-family: "Courier New", monospace;
  font-size: 1.2rem;
  font-weight: bold;
  color: #333;
}

.mixer-info .color-name {
  margin-top: 8px;
  font-size: 1rem;
  color: #666;
}

/* Color Diagram */
.color-diagram {
  display: flex;
  justify-content: center;
  margin: 30px 0;
}

.rgb-diagram {
  position: relative;
  width: 320px;
  height: 300px;
}

.rgb-circle {
  position: absolute;
  width: 130px;
  height: 130px;
  border-radius: 50%;
  opacity: 0.7;
}

.rgb-circle.red {
  background: #ff0000;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
}

.rgb-circle.green {
  background: #00ff00;
  bottom: 20px;
  left: 25px;
}

.rgb-circle.blue {
  background: #0000ff;
  bottom: 20px;
  right: 25px;
}

.rgb-label {
  position: absolute;
  font-weight: bold;
  font-size: 0.85rem;
  color: white;
  text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
  white-space: nowrap;
  padding: 4px 10px;
  border-radius: 15px;
}

.rgb-label.red-label {
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  background: #cc0000;
}

.rgb-label.green-label {
  bottom: 0;
  left: 20px;
  background: #00aa00;
  color: white;
}

.rgb-label.blue-label {
  bottom: 0;
  right: 20px;
  background: #0000cc;
}

.rgb-label.center-label {
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: #333;
  text-shadow: none;
  background: white;
  border: 2px solid #333;
  z-index: 10;
}

.rgb-label.yellow-label {
  top: 125px;
  left: 60px;
  color: #333;
  background: #e6e600;
  text-shadow: none;
  transform: rotate(-45deg);
}

.rgb-label.cyan-label {
  bottom: 75px;
  left: 50%;
  transform: translateX(-50%);
  color: #333;
  background: #00e6e6;
  text-shadow: none;
}

.rgb-label.magenta-label {
  top: 120px;
  right: 40px;
  color: white;
  background: #e600e6;
  transform: rotate(45deg);
}

/* Category Headers for Theory 11 */
.category-header.basics {
  border-color: #e53935;
}

.category-header.colors {
  border-color: #38ef7d;
}

.category-header.mixer {
  border-color: #f093fb;
}

.category-header.examples {
  border-color: #667eea;
}

/* Category Icons for Theory 11 */
.category-icon.basics {
  background: linear-gradient(145deg, #e53935 0%, #ff6f00 100%);
}

.category-icon.colors {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.category-icon.mixer {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.category-icon.examples {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

/* Category Description for Theory 11 */
.category-description {
  border-left-color: #e53935;
}

/* Formula Parts */
.formula-part {
  display: inline-block;
  padding: 5px 10px;
  border-radius: 5px;
  margin: 2px;
}

.formula-part.protocol {
  background: linear-gradient(145deg, #e94560 0%, #ff6b6b 100%);
}

.formula-part.separator {
  background: #607d8b;
}

.formula-part.domain {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.formula-part.path {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.formula-part.file {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

/* Example Box */
.example-box {
  background: #263238;
  border-radius: 12px;
  padding: 20px;
  margin: 15px 0;
  overflow-x: auto;
}

.example-box h4 {
  color: #4fc3f7;
  margin-bottom: 12px;
  font-size: 1rem;
}

/* Example URL */
.example-url {
  font-family: "Consolas", "Courier New", monospace;
  font-size: 1rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 2px;
}

/* URL Parts */
.url-part {
  padding: 4px 8px;
  border-radius: 4px;
  font-weight: 500;
}

.url-part.protocol {
  background: rgba(233, 69, 96, 0.3);
  color: #ff6b6b;
}

.url-part.separator {
  background: rgba(96, 125, 139, 0.3);
  color: #b0bec5;
}

.url-part.domain {
  background: rgba(17, 153, 142, 0.3);
  color: #38ef7d;
}

.url-part.path {
  background: rgba(240, 147, 251, 0.3);
  color: #f5576c;
}

.url-part.file {
  background: rgba(102, 126, 234, 0.3);
  color: #a18cd1;
}

/* Protocols Grid */
.protocols-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 12px;
}

.protocol-item {
  background: linear-gradient(145deg, #f5f7fa 0%, #e4e8eb 100%);
  border-radius: 10px;
  padding: 15px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  border: 2px solid transparent;
}

.protocol-item:hover {
  transform: translateY(-3px);
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  border-color: #e94560;
}

.protocol-name {
  font-family: "Consolas", "Courier New", monospace;
  font-size: 1.1rem;
  font-weight: 600;
  color: #333;
  margin-bottom: 5px;
}

.protocol-desc {
  font-size: 0.8rem;
  color: #666;
}

/* Steps Section */
.steps-section {
  background: rgba(255, 255, 255, 0.95);
  border-radius: 15px;
  padding: 25px;
  margin-bottom: 25px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.step-item {
  display: flex;
  gap: 15px;
  margin-bottom: 20px;
  padding: 15px;
  background: #f8f9fa;
  border-radius: 10px;
  align-items: flex-start;
}

.step-number {
  width: 40px;
  height: 40px;
  min-width: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  color: white;
  font-size: 1.2rem;
}

.step-number.step1 {
  background: linear-gradient(145deg, #e94560 0%, #ff6b6b 100%);
}

.step-number.step2 {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.step-number.step3 {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.step-number.step4 {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

.step-content h4 {
  color: #333;
  margin-bottom: 8px;
}

.step-content p {
  color: #666;
  line-height: 1.6;
}

/* Interactive Demo */
.interactive-demo {
  background: #1a1a2e;
  border-radius: 15px;
  padding: 25px;
  margin: 20px 0;
}

.interactive-demo h3 {
  color: white;
  margin-bottom: 20px;
  text-align: center;
}

.demo-builder {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.demo-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.demo-label {
  color: #b0bec5;
  min-width: 100px;
}

.demo-input {
  flex: 1;
  min-width: 200px;
  padding: 10px 15px;
  border: 2px solid #37474f;
  border-radius: 8px;
  background: #263238;
  color: white;
  font-family: "Consolas", monospace;
  font-size: 1rem;
}

.demo-input:focus {
  outline: none;
  border-color: #667eea;
}

.demo-result {
  margin-top: 15px;
  padding: 15px;
  background: #263238;
  border-radius: 10px;
  font-family: "Consolas", monospace;
  font-size: 1rem;
  word-break: break-all;
  min-height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.demo-result.has-content {
  color: #4fc3f7;
}

.demo-result.empty {
  color: #607d8b;
}

/* Back Link */
.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.2);
  color: white;
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 25px;
  transition: background 0.3s;
  font-weight: 500;
}

.back-link:hover {
  background: rgba(255, 255, 255, 0.3);
}

/* Category Headers for Theory 4 */
.category-header.protocol {
  border-color: #e94560;
}

.category-header.domain {
  border-color: #38ef7d;
}

.category-header.path {
  border-color: #f093fb;
}

.category-header.file {
  border-color: #667eea;
}

/* Category Icons for Theory 4 */
.category-icon.protocol {
  background: linear-gradient(145deg, #e94560 0%, #ff6b6b 100%);
}

.category-icon.domain {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.category-icon.path {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.category-icon.file {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

/* Theory Intro List */
.theory-intro ul {
  margin-left: 30px;
}

/* Theory Intro List Items */
.theory-intro li {
  margin-bottom: 8px;
  line-height: 1.6;
}

/* Category Headers for Theory 6 */
.category-header.fano {
  border-color: #4ca1af;
}

.category-header.decode {
  border-color: #38ef7d;
}

.category-header.examples {
  border-color: #f093fb;
}

.category-header.tips {
  border-color: #ff6b6b;
}

/* Category Icons for Theory 6 */
.category-icon.fano {
  background: linear-gradient(145deg, #2c3e50 0%, #4ca1af 100%);
}

.category-icon.decode {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.category-icon.examples {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.category-icon.tips {
  background: linear-gradient(145deg, #eb3349 0%, #f45c43 100%);
}

/* Category Headers for Theory 9 */
.category-header.formula {
  border-color: #1e3c72;
}

.category-header.units {
  border-color: #2a5298;
}

.category-header.calculation {
  border-color: #4facfe;
}

/* Category Icons for Theory 9 */
.category-icon.formula {
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
}

.category-icon.units {
  background: linear-gradient(145deg, #2a5298 0%, #4facfe 100%);
}

.category-icon.calculation {
  background: linear-gradient(145deg, #4facfe 0%, #00f2fe 100%);
}

/* Code Table Demo */
.code-table-demo {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.code-table-demo th,
.code-table-demo td {
  border: 2px solid #e0e0e0;
  padding: 12px 15px;
  text-align: center;
  min-width: 80px;
}

.code-table-demo th {
  background: linear-gradient(145deg, #2c3e50 0%, #4ca1af 100%);
  color: white;
  font-weight: 600;
}

.code-table-demo td {
  font-family: "Courier New", monospace;
  font-size: 1.1rem;
  font-weight: bold;
  color: #2c3e50;
}

/* Example Task Highlight */
.example-task .highlight {
  background: linear-gradient(145deg, #2c3e50 0%, #4ca1af 100%);
  color: white;
  padding: 2px 8px;
  border-radius: 5px;
  font-weight: bold;
  font-family: "Courier New", monospace;
}

/* Decode Demo */
.decode-demo {
  background: #f8f9fa;
  border: 2px solid #4ca1af;
  border-radius: 10px;
  padding: 20px;
  margin: 20px 0;
  font-family: "Courier New", monospace;
}

.decode-demo .code-part {
  display: inline-block;
  padding: 3px 8px;
  margin: 2px;
  border-radius: 5px;
  font-weight: bold;
}

.decode-demo .code-part.found {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
  color: white;
}

.decode-demo .code-part.remaining {
  background: #e0e0e0;
  color: #666;
}

.decode-demo .letter-result {
  color: #11998e;
  font-weight: bold;
  font-size: 1.2rem;
}

.decode-demo .arrow {
  color: #4ca1af;
  font-size: 1.2rem;
  margin: 0 10px;
}

/* Condition Card Details */
.condition-card h5 {
  color: #4ca1af;
  margin-bottom: 10px;
  font-size: 1rem;
}

.condition-card p {
  color: #555;
  font-size: 0.9rem;
  line-height: 1.6;
}

.condition-card code {
  background: #f0f0f0;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "Courier New", monospace;
}

/* Success and Warning Box Lists */
.success-box ul {
  margin-left: 20px;
  line-height: 1.8;
}

.warning-box ul {
  margin-left: 20px;
  color: #856404;
}

/* Category Headers for Theory 5 */
.category-header.method {
  border-color: #667eea;
}

.category-header.table {
  border-color: #38ef7d;
}

/* Category Icons for Theory 5 */
.category-icon.method {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

.category-icon.table {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

/* Condition Types */
.condition-types {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 15px;
  margin: 20px 0;
}

.condition-card {
  background: linear-gradient(145deg, #f8f9fa 0%, #e9ecef 100%);
  border-radius: 12px;
  padding: 20px;
  border-left: 4px solid #667eea;
}

.condition-card h5 {
  color: #333;
  margin-bottom: 10px;
  font-size: 1rem;
}

.condition-card p {
  color: #555;
  line-height: 1.6;
  font-size: 0.95rem;
}

/* Info Box */
.info-box {
  background: linear-gradient(145deg, #e3f2fd 0%, #bbdefb 100%);
  border-radius: 12px;
  padding: 20px;
  margin: 20px 0;
  border-left: 4px solid #2196f3;
}

.info-box h4 {
  color: #1565c0;
  margin-bottom: 15px;
}

.info-box p {
  color: #1976d2;
  line-height: 1.7;
}

/* Logic Table Demo */
.logic-table-demo {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.logic-table-demo th,
.logic-table-demo td {
  padding: 12px 15px;
  text-align: center;
  border: 1px solid #e0e0e0;
}

.logic-table-demo th {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
  color: white;
  font-weight: 600;
}

.logic-table-demo .name-header {
  background: linear-gradient(145deg, #333 0%, #555 100%);
}

.logic-table-demo .name-cell {
  background: linear-gradient(145deg, #f5f5f5 0%, #e0e0e0 100%);
  font-weight: 600;
  color: #333;
}

.logic-table-demo .highlight {
  background: #fff9c4;
}

.logic-table-demo .minus {
  background: #ffcdd2;
  color: #c62828;
  font-weight: bold;
  font-size: 1.2rem;
}

.logic-table-demo .plus {
  background: #c8e6c9;
  color: #2e7d32;
  font-weight: bold;
  font-size: 1.2rem;
}

/* Example Task Highlight */
.example-task .highlight {
  background: linear-gradient(145deg, #e94560 0%, #ff6b6b 100%);
  color: white;
  padding: 2px 8px;
  border-radius: 5px;
  font-weight: bold;
}

/* Table Animation */
.table-animation {
  animation: fadeIn 0.5s ease-out;
}

/* Category Headers for Theory 7 */
.category-header.units {
  border-color: #1e3c72;
}

.category-header.conversion {
  border-color: #38ef7d;
}

.category-header.operations {
  border-color: #f093fb;
}

.category-header.examples {
  border-color: #ff6b6b;
}

.category-header.tips {
  border-color: #ffc107;
}

/* Category Icons for Theory 7 */
.category-icon.units {
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
}

.category-icon.conversion {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.category-icon.operations {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.category-icon.examples {
  background: linear-gradient(145deg, #eb3349 0%, #f45c43 100%);
}

.category-icon.tips {
  background: linear-gradient(145deg, #f7971e 0%, #ffd200 100%);
}

/* Category Description for Theory 7 */
.category-description {
  border-left-color: #1e3c72;
}

/* Units Table for Theory 7 */
.units-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.units-table th,
.units-table td {
  border: 2px solid #e0e0e0;
  padding: 12px 15px;
  text-align: center;
}

.units-table th {
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
  font-weight: 600;
}

.units-table td {
  font-size: 1rem;
  color: #333;
}

.units-table td:first-child {
  font-weight: bold;
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
}

/* Task Type Badge */
.task-type-badge {
  display: inline-block;
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 5px 15px;
  border-radius: 20px;
  font-size: 0.85rem;
  margin-bottom: 10px;
}

/* Example Card for Theory 7 */
.example-card {
  background: white;
  border-radius: 12px;
  padding: 20px;
  margin: 15px 0;
  border: 2px solid #e0e0e0;
  transition: border-color 0.3s;
}

.example-card:hover {
  border-color: #2a5298;
}

.example-card h4 {
  color: #333;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Example Task for Theory 7 */
.example-task {
  background: #f8f9fa;
  padding: 15px;
  border-radius: 8px;
  margin-bottom: 12px;
  border-left: 4px solid #1e3c72;
  line-height: 1.7;
}

.example-task .highlight {
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
  padding: 2px 8px;
  border-radius: 5px;
  font-weight: bold;
  font-family: "Courier New", monospace;
  white-space: nowrap;
  display: inline-block;
}

/* Example Solution for Theory 7 */
.example-solution {
  background: #e8f5e9;
  padding: 15px;
  border-radius: 8px;
  border-left: 4px solid #38ef7d;
}

.example-solution strong {
  color: #11998e;
}

/* Formula Box for Theory 7 */
.formula-box {
  background: #f0f4f8;
  border: 2px solid #1e3c72;
  border-radius: 10px;
  padding: 20px;
  margin: 15px 0;
  text-align: center;
}

.formula-box .formula {
  font-size: 1.3rem;
  font-family: "Courier New", monospace;
  color: #1e3c72;
  font-weight: bold;
}

.formula-box .formula-label {
  font-size: 0.9rem;
  color: #666;
  margin-top: 10px;
}

/* Conversion Demo for Theory 7 */
.conversion-demo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
  flex-wrap: wrap;
  margin: 20px 0;
  padding: 20px;
  background: #f8f9fa;
  border-radius: 10px;
}

.conversion-arrow {
  font-size: 1.5rem;
  color: #2a5298;
}

.conversion-value {
  padding: 10px 20px;
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
  border-radius: 8px;
  font-weight: bold;
  font-size: 1.1rem;
}

.conversion-unit {
  font-size: 0.9rem;
  color: #666;
}

/* Step List for Theory 7 */
.step-list {
  counter-reset: step-counter;
  list-style: none;
  padding-left: 0;
}

.step-list li {
  position: relative;
  padding: 10px 10px 10px 50px;
  margin-bottom: 10px;
  background: #f8f9fa;
  border-radius: 8px;
  counter-increment: step-counter;
  line-height: 1.6;
}

.step-list li::before {
  content: counter(step-counter);
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  width: 30px;
  height: 30px;
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
}

/* Warning Box for Theory 7 */
.warning-box {
  background: #fff3cd;
  border-left: 4px solid #ffc107;
  padding: 15px 20px;
  margin: 15px 0;
  border-radius: 0 10px 10px 0;
}

.warning-box h4 {
  color: #856404;
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.warning-box ul {
  margin-left: 20px;
  color: #856404;
}

/* Success Box for Theory 7 */
.success-box {
  background: #d4edda;
  border-left: 4px solid #38ef7d;
  padding: 15px 20px;
  margin: 15px 0;
  border-radius: 0 10px 10px 0;
}

.success-box h4 {
  color: #155724;
  margin-bottom: 10px;
}

.success-box ul {
  margin-left: 20px;
  line-height: 1.8;
}

/* Info Box for Theory 7 */
.info-box {
  background: #e3f2fd;
  border-left: 4px solid #2196f3;
  padding: 15px 20px;
  margin: 15px 0;
  border-radius: 0 10px 10px 0;
}

.info-box h4 {
  color: #1565c0;
  margin-bottom: 10px;
}

.info-box p {
  color: #1565c0;
  line-height: 1.6;
}

/* Filter Buttons for Theory 7 */
.filter-btn:hover,
.filter-btn.active {
  color: #1e3c72;
}

/* Quick Nav for Theory 7 */
.quick-nav-btn.top {
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
}

/* Encoding Table for Task 10 */
.encoding-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.encoding-table th,
.encoding-table td {
  border: 2px solid #e0e0e0;
  padding: 12px 15px;
  text-align: center;
}

.encoding-table th {
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
  font-weight: 600;
}

.encoding-table td {
  font-size: 1rem;
  color: #333;
}

.encoding-table td:first-child {
  font-weight: bold;
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
}

/* Sentence Style for Task 10 */
.sentence {
  display: inline-block;
  background: linear-gradient(145deg, #e94560 0%, #ff6b6b 100%);
  color: white;
  padding: 4px 12px;
  border-radius: 8px;
  font-weight: bold;
  font-style: italic;
  margin: 8px 0;
}

/* Character Highlight for Task 10 */
.char-highlight {
  display: inline-block;
  background: linear-gradient(145deg, #1e3c72 0%, #2a5298 100%);
  color: white;
  padding: 4px 10px;
  border-radius: 6px;
  font-weight: bold;
  font-family: "Courier New", monospace;
  margin: 2px;
}

/* Format Table for Task 12 */
.format-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  background: white;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.format-table th,
.format-table td {
  border: 2px solid #e0e0e0;
  padding: 12px 15px;
  text-align: left;
}

.format-table th {
  background: linear-gradient(145deg, #0f4c75 0%, #3282b8 100%);
  color: white;
  font-weight: 600;
}

.format-table td {
  font-size: 0.95rem;
  vertical-align: top;
}

.format-table tr:nth-child(even) {
  background: #f8f9fa;
}

/* Format Demo for Task 12 */
.format-demo {
  padding: 15px;
  background: #f8f9fa;
  border-radius: 8px;
  margin: 15px 0;
  border: 1px solid #e0e0e0;
}

.format-demo-label {
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 8px;
  font-weight: bold;
}

/* Word Demo Interface for Task 12 */
.word-demo {
  border: 2px solid #d1d5db;
  border-radius: 8px;
  overflow: hidden;
  background: white;
  margin: 20px 0;
}

.word-toolbar {
  background: linear-gradient(180deg, #f3f4f6 0%, #e5e7eb 100%);
  padding: 8px 15px;
  border-bottom: 1px solid #d1d5db;
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.85rem;
  color: #374151;
}

.word-ruler {
  background: #f9fafb;
  height: 25px;
  border-bottom: 1px solid #d1d5db;
  position: relative;
  margin-left: 40px;
}

/* Ruler Indent Markers for Task 12 */
.ruler-indent-marker {
  position: absolute;
  top: 0;
  font-size: 1.2rem;
}

.indent-marker-left {
  left: 50px;
  color: #4b5563;
}

.indent-marker-first {
  left: 80px;
  top: 5px;
  color: #3b82f6;
}

.indent-marker-hanging {
  left: 30px;
  color: #ef4444;
}

.indent-marker-right {
  right: 30px;
  color: #4b5563;
}

/* Document Area for Task 12 */
.document-area {
  padding: 20px 40px;
  min-height: 80px;
  background: white;
  font-family: "Times New Roman", Times, serif;
  font-size: 14pt;
  line-height: 1.8;
}

.doc-para {
  margin-bottom: 10px;
  color: #1f2937;
}

/* Demo Indent Styles for Task 12 */
.demo-first-indent {
  text-indent: 1.5cm;
}

.demo-hanging-indent {
  text-indent: -1cm;
  margin-left: 2cm;
}

.demo-left-indent {
  margin-left: 2cm;
}

.demo-right-indent {
  margin-right: 2cm;
  text-align: right;
}

/* Demo Alignment Styles for Task 12 */
.demo-align-left {
  text-align: left;
}

.demo-align-right {
  text-align: right;
}

.demo-align-center {
  text-align: center;
}

.demo-align-justify {
  text-align: justify;
}

/* Ruler Diagram for Task 12 */
.ruler-diagram {
  display: flex;
  justify-content: center;
  margin: 30px 0;
}

.ruler-visual {
  position: relative;
  width: 100%;
  max-width: 600px;
  background: #f9fafb;
  border: 2px solid #d1d5db;
  border-radius: 8px;
  padding: 40px 20px 20px;
}

.ruler-line {
  position: absolute;
  top: 15px;
  left: 20px;
  right: 20px;
  height: 2px;
  background: #9ca3af;
}

/* Marker Items for Task 12 */
.marker-item {
  display: flex;
  align-items: center;
  gap: 15px;
  margin: 15px 0;
  padding: 12px;
  background: white;
  border-radius: 8px;
  border: 1px solid #e0e0e0;
}

.marker-symbol {
  font-size: 1.5rem;
  width: 40px;
  text-align: center;
}

.marker-desc {
  flex: 1;
}

.marker-desc strong {
  color: #333;
  display: block;
  margin-bottom: 4px;
}

.marker-desc span {
  color: #666;
  font-size: 0.9rem;
}

/* Category Headers for Task 12 */
.category-header.indents {
  border-color: #0f4c75;
}

.category-header.alignment {
  border-color: #38ef7d;
}

.category-header.ruler {
  border-color: #f093fb;
}

.category-header.examples {
  border-color: #667eea;
}

/* Category Icons for Task 12 */
.category-icon.indents {
  background: linear-gradient(145deg, #0f4c75 0%, #3282b8 100%);
}

.category-icon.alignment {
  background: linear-gradient(145deg, #11998e 0%, #38ef7d 100%);
}

.category-icon.ruler {
  background: linear-gradient(145deg, #f093fb 0%, #f5576c 100%);
}

.category-icon.examples {
  background: linear-gradient(145deg, #667eea 0%, #764ba2 100%);
}

/* Filter Button Hover for Task 12 */
.filter-btn:hover,
.filter-btn.active {
  color: #0f4c75;
}

/* Quick Nav Button Top for Task 12 */
.quick-nav-btn.top {
  background: linear-gradient(145deg, #0f4c75 0%, #3282b8 100%);
}

/* Responsive for Demo */
@media (max-width: 600px) {
  .demo-row {
    flex-direction: column;
    align-items: flex-start;
  }

  .demo-input {
    width: 100%;
  }

  .condition-types {
    grid-template-columns: 1fr;
  }

  .units-table th,
  .units-table td,
  .encoding-table th,
  .encoding-table td {
    padding: 8px 10px;
    font-size: 0.85rem;
  }

  .format-table th,
  .format-table td {
    padding: 8px 10px;
    font-size: 0.85rem;
  }

  .document-area {
    padding: 15px 20px;
  }

  .word-ruler {
    margin-left: 20px;
  }
}