:root {
  --bg-color: #1a1a1a;
  --text-color: #e0e0e0;
  --secondary-text: #b0b0b0;
  --border-color: #444;
  --hover-bg: #2a2a2a;
  --correct-bg: #1a4d1a;
  --correct-border: #2ecc71;
  --incorrect-bg: #4d1a1a;
  --incorrect-border: #e74c3c;
  --button-bg: #0056b3;
  --button-text: #ffffff;
  --button-hover: #003d82;
  --code-bg: #2d2d2d;
}

[data-theme="light"] {
  --bg-color: #ffffff;
  --text-color: #000000;
  --secondary-text: #444;
  --border-color: #ccc;
  --hover-bg: #f5f5f5;
  --correct-bg: #c8f7c5;
  --correct-border: #2ecc71;
  --incorrect-bg: #f7c5c5;
  --incorrect-border: #e74c3c;
  --button-bg: #007bff;
  --button-text: #ffffff;
  --button-hover: #0056b3;
  --code-bg: #f6f8fa;
}

* {
  transition:
    background-color 0.3s ease,
    color 0.3s ease,
    border-color 0.3s ease;
}

body {
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica,
    Arial, sans-serif;
  margin: 0;
  padding: 0;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
}

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background-color: var(--bg-color);
  border-bottom: 1px solid var(--border-color);
  padding: 12px 20px;
  z-index: 999;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.navbar-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-links {
  display: flex;
  gap: 20px;
  justify-content: center;
  align-items: center;
}

.nav-links a,
.back-link {
  color: var(--text-color);
  text-decoration: none;
  padding: 8px 16px;
  border-radius: 6px;
  transition: background-color 0.3s ease;
}

.nav-links a:hover,
.back-link:hover {
  background-color: var(--hover-bg);
}

.hamburger {
  display: none;
  background: none;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  padding: 4px;
  z-index: 1001;
}

.hamburger:hover {
  background-color: var(--hover-bg);
}

.hamburger svg {
  fill: var(--text-color);
  color: var(--text-color);
  height: 26px;
  width: 26px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hamburger svg path.menu-icon {
  display: block;
}

.hamburger svg path.close-icon {
  display: none;
}

.hamburger.active svg path.menu-icon {
  display: none;
}

.hamburger.active svg path.close-icon {
  display: block;
}

.body-content {
  padding: 100px 20px;
}

.theme-toggle-container {
  opacity: 0.7;
  transition: opacity 0.3s ease;
}

.theme-toggle-container:hover {
  opacity: 1;
}

.toggle-switch {
  position: relative;
  display: inline-flex;
  background-color: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: 100px;
  padding: 4px;
  cursor: pointer;
  gap: 4px;
}

.toggle-switch::before {
  content: "";
  position: absolute;
  width: 34px;
  height: 30px;
  background-color: #3a4a5a;
  border-radius: 100px;
  top: 4px;
  left: 4px;
  transform: translateX(37px);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 0;
}

[data-theme="light"] .toggle-switch::before {
  background-color: var(--secondary-text);
  transform: translateX(0);
}

.toggle-option {
  position: relative;
  width: 34px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
}

.toggle-icon {
  pointer-events: none;
  transition: stroke 0.3s ease;
}

.sun-icon {
  stroke: var(--secondary-text);
}

.moon-icon {
  stroke: #fff;
}

[data-theme="light"] .sun-icon {
  stroke: #fff;
}

[data-theme="light"] .moon-icon {
  stroke: var(--secondary-text);
}

h1 {
  text-align: center;
}

#timer {
  font-size: 1.25rem;
  font-weight: bold;
  color: var(--secondary-text);
  margin-bottom: 20px;
  display: none;
}

#examContainer {
  max-width: 900px;
  margin: 100px auto 20px;
}

#progress {
  margin-bottom: 20px;
  font-weight: bold;
  margin-bottom: 20px;
  font-size: 1.25rem;
}

#question {
  margin-bottom: 1rem;
}

#question pre {
  background-color: var(--code-bg);
  padding: 16px;
  border-radius: 6px;
  overflow-x: auto;
  margin: 16px 0;
  border: 1px solid var(--border-color);
  font-family:
    ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono",
    monospace;
  font-size: 0.6em;
  line-height: 1.5;
}

.option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  margin: 8px 0;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  cursor: pointer;
  background-color: var(--bg-color);
}

.option:hover {
  background: var(--hover-bg);
}

.option.selected {
  background: var(--hover-bg);
  border-color: var(--button-bg);
}

.option-checkbox {
  display: none;
}

.option label {
  cursor: pointer;
  flex: 1;
  margin: 0;
}

.correct,
.correct.option:hover,
.correct.option.selected,
.correct.option.selected:hover {
  background: var(--correct-bg);
  border-color: var(--correct-border);
}

.incorrect,
.incorrect.option:hover,
.incorrect.option.selected,
.incorrect.option.selected:hover {
  background: var(--incorrect-bg);
  border-color: var(--incorrect-border);
}

#feedback {
  margin-top: 20px;
  font-weight: bold;
}

#nextBtn,
#endBtn,
.submit-answer-btn {
  padding: 10px 20px;
  font-size: 1rem;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  border-radius: 6px;
  cursor: pointer;
}

.submit-answer-btn {
  margin-top: 12px;
}

#nextBtn:hover,
#endBtn:hover,
.submit-answer-btn:hover {
  background-color: var(--button-hover);
}

#buttonRow {
  margin-top: 20px;
  display: none;
  justify-content: space-between;
  align-items: center;
}

#controls {
  margin-bottom: 30px;
  display: flex;
  gap: 10px;
  justify-content: center;
}

#controls button {
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: bold;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  background-color: var(--button-bg);
  color: var(--button-text);
}

#controls button:hover {
  background-color: var(--button-hover);
}

#startBtn {
  background-color: #28a745 !important;
  margin-top: 50px;
}

#startBtn:hover {
  background-color: #218838 !important;
}

#endBtn {
  color: #dc3545;
  border: 1px solid #dc3545;
  background-color: transparent;
}

#endBtn:hover {
  background-color: #c82333;
  color: var(--button-text);
}

#result {
  margin-top: 30px;
  font-size: 1.25rem;
  font-weight: bold;
}

.pass {
  color: green;
}

.fail {
  color: red;
}

.review {
  margin-top: 30px;
}

@media (max-width: 1024px) {
  body {
    font-size: 0.9rem;
  }

  .theme-toggle-container {
    top: 10px;
    right: 10px;
  }

  .toggle-switch::before {
    width: 26px;
    height: 22px;
    transform: translateX(29px);
  }

  .toggle-option {
    width: 26px;
    height: 22px;
  }

  .toggle-icon {
    width: 14px;
    height: 14px;
  }

  h1 {
    font-size: 1.75rem;
  }

  h3 {
    font-size: 1.5rem;
  }

  #examContainer {
    margin-top: 75px;
  }

  #timer,
  #progress,
  #result {
    font-size: 1.1rem;
  }
}

@media (max-width: 768px) {
  body {
    font-size: 0.85rem;
  }

  .hamburger {
    display: flex;
  }

  .navbar-container {
    flex-wrap: wrap;
  }

  .nav-links {
    position: fixed;
    top: 58px;
    left: 0;
    right: 0;
    flex-direction: column;
    background-color: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition:
      max-height 0.3s ease,
      padding 0.3s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    gap: 0;
  }

  .nav-links.active {
    max-height: 300px;
    padding: 12px 0;
  }

  .nav-links a {
    width: 100%;
    text-align: center;
    padding: 12px 20px;
    border-radius: 0;
  }

  h1 {
    font-size: 1.5rem;
  }

  h3 {
    font-size: 1.25rem;
  }

  #examContainer {
    margin-top: 50px;
  }

  #timer,
  #progress,
  #result {
    font-size: 1rem;
  }

  .body-content {
    padding: 80px 15px;
  }

  #controls button,
  #nextBtn,
  #endBtn {
    font-size: 0.9rem;
    padding: 8px 16px;
  }
}