:root {
  --backdrop: #f5f5f7;
  --nav-color: #2d1b2e;
  --nav-accent: #4a2c4b;
  --text-color: #fcfafa;
  --card-bg: #ffffff;
  --border-color: #e0e0e0;
  --button-primary: #6b4c9a;
  --button-hover: #553d7a;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background: var(--backdrop);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, sans-serif;
  margin: 0;
  padding: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Navigation */
.navigation {
  background: var(--nav-color);
  width: 100%;
  box-shadow: var(--shadow-md);
}

.navigation-title {
  text-align: center;
  letter-spacing: 0.8rem;
  color: var(--text-color);
  font-size: 1.5rem;
  font-weight: 700;
  padding: 1.2rem 0 0.8rem 0;
  margin: 0;
}

.navbar {
  background-color: transparent;
  width: 100%;
}

.navbar-list {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 2rem;
  list-style: none;
  margin: 0;
  padding: 0.8rem 0 1rem 0;
}

.navbar-list li {
  display: inline-block;
}

.navbar-list a {
  font-family: inherit;
  letter-spacing: 1px;
  padding: 0.6rem 1.5rem;
  display: inline-block;
  text-decoration: none;
  color: var(--text-color);
  font-weight: 500;
  border-radius: 6px;
  transition: all 0.3s ease;
  position: relative;
}

.navbar-list a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: var(--text-color);
  transition: width 0.3s ease;
}

.navbar-list a:hover,
.navbar-list a:focus {
  background: rgba(255, 255, 255, 0.1);
  cursor: pointer;
}

.navbar-list a:hover::after {
  width: 60%;
}

/* Main Content */
main {
  padding-top: 1.5rem;
  flex: 1;
  display: flex;
  justify-content: center;
  padding-bottom: 1.5rem;
  padding-left: 20px;
  padding-right: 20px;
}

.wrap {
  width: 100%;
  max-width: 1400px;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

/* Toolbar */
.toolbar {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 16px;
  box-shadow: var(--shadow-md);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1.5rem;
  border: 1px solid var(--border-color);
}

.toolbar > label {
  font-weight: 600;
  color: #333;
  font-size: 0.95rem;
}

.toolbar select {
  padding: 0.65rem 1rem;
  border: 2px solid var(--border-color);
  border-radius: 8px;
  background: white;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: inherit;
  color: #333;
  min-width: 220px;
}

.toolbar select:hover {
  border-color: var(--button-primary);
}

.toolbar select:focus {
  outline: none;
  border-color: var(--button-primary);
  box-shadow: 0 0 0 3px rgba(107, 76, 154, 0.1);
}

.checks {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  flex: 1;
}

.checks label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem;
  color: #555;
  font-weight: 500;
  transition: color 0.2s ease;
  user-select: none;
}

.checks label:hover {
  color: var(--button-primary);
}

.checks input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--button-primary);
}

.toolbar button {
  padding: 0.75rem 2rem;
  background: linear-gradient(
    135deg,
    var(--button-primary) 0%,
    var(--button-hover) 100%
  );
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-sm);
  font-family: inherit;
  letter-spacing: 0.5px;
}

.toolbar button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.toolbar button:active {
  transform: translateY(0);
  box-shadow: var(--shadow-sm);
}

/* Canvas Container */
.canvas-container {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 1.5rem;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border-color);
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
  max-height: 65vh;
}

.canvas-container figure {
  margin: 0;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
}

canvas {
  display: block;
  border-radius: 12px;
  max-width: 100%;
  max-height: 60vh;
  height: auto;
  width: auto;
  object-fit: contain;
}

/* Content Sections */
.content {
  background: var(--card-bg);
  border-radius: 16px;
  padding: 2.5rem;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  margin-bottom: 2rem;
  max-width: 1400px;
  width: 100%;
}

.content h2 {
  color: var(--nav-color);
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  padding-bottom: 0.75rem;
  border-bottom: 3px solid var(--button-primary);
}

.content h3 {
  color: var(--nav-accent);
  font-size: 1.3rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.content p {
  color: #444;
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 1.2rem;
}

.content ol {
  color: #444;
  font-size: 1.05rem;
  line-height: 1.7;
  margin-left: 1.5rem;
  margin-bottom: 1.2rem;
}

.content li {
  margin-bottom: 0.8rem;
  padding-left: 0.5rem;
}

.content strong {
  color: var(--button-primary);
  font-weight: 600;
}

/* Scroll to Top Button */
#scrollToTop {
  position: fixed;
  bottom: 30px;
  right: 30px;
  background: linear-gradient(
    135deg,
    var(--button-primary) 0%,
    var(--button-hover) 100%
  );
  color: white;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  border: none;
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  box-shadow: var(--shadow-lg);
  transition: all 0.3s ease;
  z-index: 1000;
}

#scrollToTop:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(107, 76, 154, 0.4);
}

#scrollToTop:active {
  transform: translateY(-1px);
}

#scrollToTop.show {
  display: flex;
}

/* Footer */
footer {
  text-align: center;
  width: 100%;
  background: var(--nav-color);
  color: white;
  padding: 1rem;
  font-size: 0.9rem;
  box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.1);
  margin-top: 2rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .navigation-title {
    letter-spacing: 0.4rem;
    font-size: 1.2rem;
    padding: 1rem 0 0.6rem 0;
  }

  .navbar-list {
    gap: 1rem;
    padding: 0.6rem 0 0.8rem 0;
  }

  .navbar-list a {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
  }

  main {
    padding-top: 2rem;
    padding-bottom: 2rem;
    padding-left: 10px;
    padding-right: 10px;
  }

  .wrap {
    gap: 1rem;
  }

  .toolbar {
    padding: 1.2rem;
    gap: 1rem;
  }

  .checks {
    gap: 0.8rem;
    width: 100%;
  }

  .checks label {
    font-size: 0.85rem;
  }

  .toolbar select {
    width: 100%;
  }

  .toolbar button {
    width: 100%;
  }

  .canvas-container {
    padding: 0.8rem;
    max-height: 60vh;
  }

  canvas {
    max-height: 55vh;
  }

  .content {
    padding: 1.5rem;
    margin-bottom: 1.5rem;
  }

  .content h2 {
    font-size: 1.5rem;
  }

  .content h3 {
    font-size: 1.15rem;
  }

  .content p,
  .content ol {
    font-size: 1rem;
  }
}

@media (max-width: 480px) {
  .navigation-title {
    letter-spacing: 0.2rem;
    font-size: 1rem;
    padding: 0.8rem 0 0.5rem 0;
  }

  .navbar-list {
    flex-direction: row;
    padding: 0.5rem 0 0.6rem 0;
  }

  .navbar-list a {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
  }

  main {
    padding-top: 1.5rem;
    padding-bottom: 1.5rem;
    padding-left: 8px;
    padding-right: 8px;
  }

  .wrap {
    gap: 0.8rem;
  }

  .toolbar {
    padding: 1rem;
    gap: 0.8rem;
  }

  .canvas-container {
    padding: 0.5rem;
    max-height: 50vh;
  }

  canvas {
    max-height: 45vh;
  }

  .content {
    padding: 1.2rem;
    margin-bottom: 1rem;
  }

  .content h2 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
  }

  .content h3 {
    font-size: 1.1rem;
    margin-top: 1.5rem;
  }

  .content p,
  .content ol {
    font-size: 0.95rem;
  }

  .content ol {
    margin-left: 1.2rem;
  }

  #scrollToTop {
    bottom: 20px;
    right: 20px;
    width: 45px;
    height: 45px;
    font-size: 1.3rem;
  }
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(1px, 1px, 1px, 1px);
  white-space: nowrap;
  border: 0;
}