/* Modern CSS Reset */
:root {
  --primary: #2c3e50;
  --primary-light: #34495e;
  --secondary: #3498db;
  --success: #2ecc71;
  --warning: #f39c12;
  --danger: #e74c3c;
  --light: #ecf0f1;
  --dark: #2c3e50;
  --gray: #95a5a6;
  --light-gray: #bdc3c7;
  
  --code-bg: #282c34;
  --code-text: #abb2bf;
  --code-comment: #5c6370;
  --code-keyword: #c678dd;
  --code-string: #98c379;
  --code-number: #d19a66;
  
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
  
  --border-radius: 8px;
  --border-radius-sm: 4px;
  
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  line-height: 1.6;
  color: var(--dark);
  background-color: #f5f7fa;
  padding: var(--spacing-md);
  min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4 {
  line-height: 1.2;
  margin-bottom: var(--spacing-sm);
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.75rem;
}

h3 {
  font-size: 1.5rem;
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  background-color: white;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

/* Header */
header {
  background-color: var(--primary);
  color: white;
  padding: var(--spacing-md);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.score-display {
  background-color: var(--primary-light);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  font-weight: bold;
  display: flex;
  gap: var(--spacing-md);
}

.score-display span {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

/* Language Tabs */
.language-tabs {
  display: flex;
  background-color: var(--primary-light);
  border-radius: var(--border-radius-sm);
  overflow: hidden;
}

.language-tab {
  padding: var(--spacing-xs) var(--spacing-sm);
  cursor: pointer;
  transition: all 0.2s;
  font-weight: bold;
  text-align: center;
  flex: 1;
}

.language-tab.active {
  background-color: var(--secondary);
}

.language-tab:hover:not(.active) {
  background-color: rgba(255, 255, 255, 0.1);
}

/* Level Selector */
.level-selector {
  display: flex;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm);
  background-color: var(--light);
  border-bottom: 1px solid var(--light-gray);
  overflow-x: auto;
}

.level-btn {
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius-sm);
  background-color: var(--light-gray);
  border: none;
  cursor: pointer;
  font-size: 0.9rem;
  transition: all 0.2s;
  white-space: nowrap;
}

.level-btn:hover {
  background-color: #d5dbdb;
}

.level-btn.active {
  background-color: var(--secondary);
  color: white;
}

/* Main Game Area */
.game-area {
  padding: var(--spacing-md);
}

.challenge-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

/* Code Panels */
.code-panel {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.panel-title {
  font-weight: bold;
  color: var(--primary);
}

.challenge-title {
  font-size: 0.9rem;
  color: var(--gray);
  background-color: var(--light);
  padding: 0.25rem 0.5rem;
  border-radius: var(--border-radius-sm);
}

/* Code Display */
pre, textarea {
  font-family: 'Fira Code', 'Consolas', 'Monaco', 'Courier New', monospace;
  font-size: 0.9rem;
  line-height: 1.5;
  tab-size: 2;
}

pre {
  background-color: var(--code-bg);
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  color: var(--code-text);
  overflow-x: auto;
  height: 300px;
  margin: 0;
}

/* Syntax Highlighting */
.token.comment {
  color: var(--code-comment);
}
.token.keyword {
  color: var(--code-keyword);
}
.token.string {
  color: var(--code-string);
}
.token.number {
  color: var(--code-number);
}

/* Code Editor */
textarea {
  width: 100%;
  height: 300px;
  padding: var(--spacing-md);
  border: 1px solid var(--light-gray);
  border-radius: var(--border-radius);
  resize: none;
  background-color: var(--code-bg);
  color: var(--code-text);
}

textarea:focus {
  outline: none;
  border-color: var(--secondary);
  box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

/* Buttons */
.button-group {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-md);
  flex-wrap: wrap;
}

.btn {
  padding: var(--spacing-xs) var(--spacing-sm);
  border: none;
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  font-weight: bold;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: 0.9rem;
}

.btn-primary {
  background-color: var(--secondary);
  color: white;
}

.btn-primary:hover {
  background-color: #2980b9;
}

.btn-success {
  background-color: var(--success);
  color: white;
}

.btn-success:hover {
  background-color: #27ae60;
}

.btn-warning {
  background-color: var(--warning);
  color: white;
}

.btn-warning:hover {
  background-color: #e67e22;
}

.btn-danger {
  background-color: var(--danger);
  color: white;
}

.btn-danger:hover {
  background-color: #c0392b;
}

.btn-info {
  background-color: var(--gray);
  color: white;
}

.btn-info:hover {
  background-color: #7f8c8d;
}

/* Output Containers */
.output-container {
  background-color: var(--light);
  border-radius: var(--border-radius);
  padding: var(--spacing-sm);
  margin-top: var(--spacing-sm);
}

.output-title {
  font-weight: bold;
  margin-bottom: var(--spacing-xs);
  display: flex;
  justify-content: space-between;
}

.output-content {
  white-space: pre-wrap;
  font-family: 'Fira Code', 'Consolas', 'Monaco', 'Courier New', monospace;
  background-color: white;
  padding: var(--spacing-sm);
  border-radius: var(--border-radius-sm);
  border: 1px solid var(--light-gray);
  min-height: 60px;
  max-height: 200px;
  overflow-y: auto;
}

.success-output {
  border-left: 4px solid var(--success);
}

.error-output {
  border-left: 4px solid var(--danger);
}

/* Feedback Messages */
.feedback {
  margin-top: var(--spacing-md);
}

.message {
  padding: var(--spacing-sm);
  border-radius: var(--border-radius-sm);
  margin-bottom: var(--spacing-sm);
  font-weight: bold;
}

.message.success {
  background-color: rgba(46, 204, 113, 0.1);
  color: var(--success);
  border-left: 4px solid var(--success);
}

.message.error {
  background-color: rgba(231, 76, 60, 0.1);
  color: var(--danger);
  border-left: 4px solid var(--danger);
}

.message.info {
  background-color: rgba(52, 152, 219, 0.1);
  color: var(--secondary);
  border-left: 4px solid var(--secondary);
}

/* Diff Output */
.diff-container {
  background-color: var(--light);
  padding: var(--spacing-sm);
  border-radius: var(--border-radius-sm);
  font-family: 'Fira Code', 'Consolas', 'Monaco', 'Courier New', monospace;
  white-space: pre-wrap;
  display: none;
}

.diff-line {
  margin-bottom: var(--spacing-xs);
  padding: 0.1rem var(--spacing-sm);
  border-radius: var(--border-radius-sm);
}

.diff-added {
  background-color: rgba(46, 204, 113, 0.2);
  border-left: 3px solid var(--success);
}

.diff-removed {
  background-color: rgba(231, 76, 60, 0.2);
  border-left: 3px solid var(--danger);
}

/* Responsive Adjustments */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--spacing-sm);
  }
  
  .language-tabs {
    width: 100%;
  }
  
  .button-group {
    justify-content: center;
  }
  
  .btn {
    flex: 1;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  body {
    padding: var(--spacing-sm);
  }
  
  .container {
    border-radius: 0;
  }
  
  .challenge-container {
    grid-template-columns: 1fr;
  }
}