/* CSS 变量 - 亮色主题 */
:root {
  --bg-primary: #f5f5f5;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f9f9f9;
  --text-primary: #333333;
  --text-secondary: #666666;
  --text-tertiary: #999999;
  --border-color: #dddddd;
  --accent-primary: #4CAF50;
  --accent-hover: #45a049;
  --danger: #f44336;
  --warning: #ff9800;
  --info: #2196f3;
  --success: #4CAF50;
  --code-bg: #f5f5f5;
  --code-text: #333;
  --editor-line-number: #999;
  --editor-line-number-bg: #f0f0f0;
}

/* 暗色主题 - 支持 data-theme 属性 */
[data-theme="dark"] {
  --bg-primary: #121212;
  --bg-secondary: #1e1e1e;
  --bg-tertiary: #252525;
  --text-primary: #e0e0e0;
  --text-secondary: #b0b0b0;
  --text-tertiary: #808080;
  --border-color: #333333;
  --accent-primary: #66bb6a;
  --accent-hover: #81c784;
  --code-bg: #1e1e1e;
  --code-text: #e0e0e0;
  --editor-line-number: #666;
  --editor-line-number-bg: #252525;
}

/* 兼容旧的 dark-mode 类 */
body.dark-mode {
  --bg-primary: #121212;
  --bg-secondary: #1e1e1e;
  --bg-tertiary: #252525;
  --text-primary: #e0e0e0;
  --text-secondary: #b0b0b0;
  --text-tertiary: #808080;
  --border-color: #333333;
  --accent-primary: #66bb6a;
  --accent-hover: #81c784;
  --code-bg: #1e1e1e;
  --code-text: #e0e0e0;
  --editor-line-number: #666;
  --editor-line-number-bg: #252525;
}

/* 全局样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 加载动画 */
@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  color: var(--text-secondary);
}

.loading::before {
  content: '';
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-right: 10px;
}

/* 头部导航 */
header {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  padding: 1rem 0;
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav h1 {
  font-size: 1.5rem;
  color: var(--accent-primary);
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

nav ul {
  display: flex;
  list-style: none;
  gap: 1.5rem;
}

nav ul li a {
  color: var(--text-primary);
  text-decoration: none;
  font-size: 1rem;
  transition: color 0.3s ease;
}

nav ul li a:hover {
  color: var(--accent-primary);
}

.theme-btn {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.5rem 1rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.3s ease;
}

.theme-btn:hover {
  background-color: var(--bg-tertiary);
}

/* 英雄区域 */
.hero {
  background: linear-gradient(135deg, var(--accent-primary) 0%, #66bb6a 100%);
  color: #fff;
  padding: 5rem 0;
  text-align: center;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.2rem;
  margin-bottom: 2rem;
  opacity: 0.95;
}

.btn {
  display: inline-block;
  background-color: #fff;
  color: var(--accent-primary);
  padding: 0.8rem 2rem;
  border-radius: 8px;
  text-decoration: none;
  font-size: 1rem;
  font-weight: bold;
  transition: all 0.3s ease;
  box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

/* 特性区域 */
.features {
  padding: 4rem 0;
  background-color: var(--bg-secondary);
}

.features h3 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 3rem;
  color: var(--text-primary);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.feature-item {
  background-color: var(--bg-tertiary);
  padding: 2.5rem 2rem;
  border-radius: 12px;
  text-align: center;
  border: 1px solid var(--border-color);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.1);
}

.feature-item h4 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: var(--accent-primary);
}

/* 题目列表 */
.problems-section {
  padding: 3rem 0;
  background-color: var(--bg-primary);
  min-height: calc(100vh - 300px);
}

.problems-section h2 {
  font-size: 2rem;
  margin-bottom: 2rem;
  color: var(--text-primary);
}

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 2rem;
  padding: 1.5rem;
  background-color: var(--bg-secondary);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.search-box {
  flex: 1;
  min-width: 200px;
  display: flex;
  gap: 0.5rem;
}

.search-box input {
  flex: 1;
  padding: 0.8rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.search-box input:focus {
  outline: none;
  border-color: var(--accent-primary);
}

.search-box button {
  padding: 0.8rem 1.5rem;
  background-color: var(--accent-primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  transition: background-color 0.3s ease;
}

.search-box button:hover {
  background-color: var(--accent-hover);
}

.category-filter, .difficulty-filter {
  min-width: 150px;
}

.category-filter select, .difficulty-filter select {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 1rem;
  cursor: pointer;
  transition: border-color 0.3s ease;
}

.category-filter select:focus, .difficulty-filter select:focus {
  outline: none;
  border-color: var(--accent-primary);
}

#problems-list {
  margin-bottom: 2rem;
}

.problem-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.2rem 1.5rem;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  margin-bottom: 1rem;
  background-color: var(--bg-secondary);
  transition: all 0.3s ease;
}

.problem-item:hover {
  background-color: var(--bg-tertiary);
  transform: translateX(4px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.problem-item a {
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1.05rem;
  transition: color 0.3s ease;
}

.problem-item a:hover {
  color: var(--accent-primary);
}

.problem-item .problem-meta {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.problem-item .category {
  background-color: var(--accent-primary);
  color: #fff;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
}

.problem-item .difficulty {
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
}

.problem-item .difficulty.easy {
  background-color: #4CAF50;
  color: #fff;
}

.problem-item .difficulty.medium {
  background-color: #ff9800;
  color: #fff;
}

.problem-item .difficulty.hard {
  background-color: #f44336;
  color: #fff;
}

.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  padding: 1.5rem;
}

.pagination button {
  padding: 0.6rem 1.2rem;
  background-color: var(--accent-primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  transition: all 0.3s ease;
}

.pagination button:hover:not(:disabled) {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
}

.pagination button:disabled {
  background-color: var(--border-color);
  cursor: not-allowed;
  color: var(--text-tertiary);
}

.pagination span {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* 题目详情 */
.problem-detail {
  padding: 3rem 0;
  background-color: var(--bg-primary);
  min-height: calc(100vh - 200px);
}

.problem-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.problem-header h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.problem-meta {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.problem-meta .category {
  background-color: var(--accent-primary);
  color: #fff;
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.9rem;
}

.problem-meta .difficulty {
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 500;
}

.problem-meta .difficulty.easy {
  background-color: #4CAF50;
  color: #fff;
}

.problem-meta .difficulty.medium {
  background-color: #ff9800;
  color: #fff;
}

.problem-meta .difficulty.hard {
  background-color: #f44336;
  color: #fff;
}

.problem-content {
  margin-bottom: 3rem;
  background-color: var(--bg-secondary);
  padding: 2rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.problem-content h3 {
  font-size: 1.3rem;
  margin: 1.5rem 0 1rem;
  color: var(--accent-primary);
}

.problem-content h3:first-child {
  margin-top: 0;
}

.problem-content div, .problem-content pre {
  color: var(--text-primary);
  line-height: 1.8;
}

.problem-sample pre {
  background-color: var(--code-bg);
  padding: 1.2rem;
  border-radius: 8px;
  overflow-x: auto;
  border: 1px solid var(--border-color);
  color: var(--code-text);
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.95rem;
  line-height: 1.6;
}

/* 代码编辑器 */
.code-editor {
  margin-bottom: 3rem;
}

.code-editor h3 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: var(--accent-primary);
}

.editor-wrapper {
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 1rem;
}

/* CodeMirror 样式覆盖 */
.CodeMirror {
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.95rem;
  line-height: 1.6;
  height: auto;
}

.CodeMirror-gutters {
  background-color: var(--editor-line-number-bg);
  border-right: 1px solid var(--border-color);
}

.CodeMirror-linenumber {
  color: var(--editor-line-number);
  padding: 0 8px 0 4px;
}

/* 暗色主题下的 CodeMirror 样式 */
[data-theme="dark"] .CodeMirror {
  background-color: var(--code-bg);
  color: var(--code-text);
}

[data-theme="dark"] .CodeMirror-gutters {
  background-color: var(--editor-line-number-bg);
}

[data-theme="dark"] .CodeMirror-linenumber {
  color: var(--editor-line-number);
}

.editor-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.editor-actions button {
  padding: 0.8rem 1.5rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  transition: all 0.3s ease;
}

#submit-btn {
  background-color: var(--accent-primary);
  color: #fff;
}

#submit-btn:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
}

#run-btn {
  background-color: var(--info);
  color: #fff;
}

#run-btn:hover {
  background-color: #1976d2;
  transform: translateY(-2px);
}

#reset-btn {
  background-color: var(--text-tertiary);
  color: #fff;
}

#reset-btn:hover {
  background-color: var(--text-secondary);
  transform: translateY(-2px);
}

#copy-btn {
  background-color: var(--warning);
  color: #fff;
}

#copy-btn:hover {
  background-color: #f57c00;
  transform: translateY(-2px);
}

/* 控制台输出 */
.console-output {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  margin-bottom: 2rem;
  overflow: hidden;
}

.console-header {
  padding: 0.8rem 1rem;
  background-color: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.console-header h4 {
  color: var(--text-primary);
  font-size: 1rem;
}

#console-text {
  padding: 1rem;
  height: 150px;
  overflow-y: auto;
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
  color: var(--text-primary);
  white-space: pre-wrap;
  line-height: 1.6;
}

/* 提交结果 */
.submission-result {
  margin-top: 2rem;
}

.submission-result h3 {
  font-size: 1.3rem;
  margin-bottom: 1rem;
  color: var(--accent-primary);
}

#result-display {
  padding: 1.5rem;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background-color: var(--bg-secondary);
  min-height: 100px;
}

.result {
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 1rem;
  padding: 1rem;
  border-radius: 8px;
  text-align: center;
}

.result.AC {
  background-color: rgba(76, 175, 80, 0.1);
  color: #4CAF50;
  border: 2px solid #4CAF50;
}

.result.WA {
  background-color: rgba(255, 152, 0, 0.1);
  color: #ff9800;
  border: 2px solid #ff9800;
}

.result.CE {
  background-color: rgba(244, 67, 54, 0.1);
  color: #f44336;
  border: 2px solid #f44336;
}

.result.RE {
  background-color: rgba(156, 39, 176, 0.1);
  color: #9c27b0;
  border: 2px solid #9c27b0;
}

.result.TLE {
  background-color: rgba(33, 150, 243, 0.1);
  color: #2196f3;
  border: 2px solid #2196f3;
}

.expected-output, .actual-output, .error-message {
  margin-top: 1rem;
  padding: 1rem;
  background-color: var(--bg-tertiary);
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.expected-output strong, .actual-output strong, .error-message strong {
  color: var(--text-primary);
  display: block;
  margin-bottom: 0.5rem;
}

.expected-output pre, .actual-output pre {
  background-color: var(--code-bg);
  padding: 1rem;
  border-radius: 4px;
  overflow-x: auto;
  color: var(--code-text);
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.9rem;
}

.error-message {
  color: var(--danger);
}

/* 用户中心 */
.user-section {
  padding: 3rem 0;
  background-color: var(--bg-primary);
  min-height: calc(100vh - 200px);
}

.user-section h2 {
  font-size: 2rem;
  margin-bottom: 2rem;
  color: var(--text-primary);
}

.auth-forms {
  display: flex;
  gap: 2rem;
  margin-bottom: 2rem;
  flex-wrap: wrap;
}

.login-form, .register-form {
  flex: 1;
  min-width: 300px;
  padding: 2rem;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background-color: var(--bg-secondary);
}

.login-form h3, .register-form h3 {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  color: var(--accent-primary);
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-primary);
}

.form-group input {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

.form-group input:focus {
  outline: none;
  border-color: var(--accent-primary);
}

.auth-forms button {
  width: 100%;
  padding: 0.9rem;
  background-color: var(--accent-primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  transition: background-color 0.3s ease, transform 0.3s ease;
}

.auth-forms button:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
}

.user-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3rem;
  padding: 2rem;
  background-color: var(--bg-secondary);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.stat-item {
  text-align: center;
  padding: 1.5rem;
  background-color: var(--bg-tertiary);
  border-radius: 8px;
}

.stat-label {
  display: block;
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.stat-value {
  display: block;
  font-size: 2rem;
  font-weight: bold;
  color: var(--accent-primary);
}

.submission-history {
  background-color: var(--bg-secondary);
  padding: 2rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.submission-history h3 {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  color: var(--accent-primary);
}

#submission-list {
  border-radius: 8px;
  overflow: hidden;
}

.submission-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.2rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-tertiary);
  transition: background-color 0.3s ease;
}

.submission-item:hover {
  background-color: var(--bg-secondary);
}

.submission-item:last-child {
  border-bottom: none;
}

.submission-item .submission-info {
  flex: 1;
}

.submission-item .problem-title {
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 0.3rem;
}

.submission-item .submission-time {
  font-size: 0.9rem;
  color: var(--text-tertiary);
}

.submission-item .submission-result {
  font-weight: bold;
  padding: 0.4rem 1rem;
  border-radius: 20px;
  font-size: 0.9rem;
}

.submission-item .submission-result.AC {
  background-color: #4CAF50;
  color: #fff;
}

.submission-item .submission-result.WA {
  background-color: #ff9800;
  color: #fff;
}

.submission-item .submission-result.CE {
  background-color: #f44336;
  color: #fff;
}

.submission-item .submission-result.RE {
  background-color: #9c27b0;
  color: #fff;
}

.submission-item .submission-result.TLE {
  background-color: #2196f3;
  color: #fff;
}

#logout-btn {
  padding: 0.9rem 1.8rem;
  background-color: var(--danger);
  color: #fff;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 500;
  margin-top: 2rem;
  transition: all 0.3s ease;
}

#logout-btn:hover {
  background-color: #d32f2f;
  transform: translateY(-2px);
}

/* 页脚 */
footer {
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 2.5rem 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
  margin-top: 3rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
  nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }
  
  .nav-right {
    width: 100%;
    justify-content: space-between;
  }
  
  nav ul {
    margin-top: 0;
    flex-wrap: wrap;
    gap: 1rem;
  }
  
  nav ul li {
    margin-left: 0;
  }
  
  .hero h2 {
    font-size: 2rem;
  }
  
  .auth-forms {
    flex-direction: column;
  }
  
  .filter-bar {
    flex-direction: column;
  }
  
  .search-box {
    flex-direction: column;
  }
  
  .search-box button {
    margin-left: 0;
    width: 100%;
  }
  
  .problem-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }
  
  .problem-item .problem-meta {
    width: 100%;
    justify-content: flex-start;
  }
  
  .editor-actions {
    flex-direction: column;
  }
  
  .editor-actions button {
    width: 100%;
  }
}