/* ============================================
   Class Whiteboard App - ChromeOS Flex Style
   ============================================ */

/* ===== CSS Variables ===== */
:root {
  --primary-blue: #1a73e8;
  --primary-blue-hover: #1557b0;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --border-color: #e8eaed;
  --bg-light: #f8f9fa;
  --bg-white: #ffffff;
  --success-green: #34a853;
  --error-red: #ea4335;
  --pastel-colors: #ffb3ba, #ffdfba, #ffffba, #baffc9, #bae1ff, #e0bbff, #ffc0cb, #dda0dd, #98d8c8, #f7dc6f;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Google Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: #ffffff;
  background-image: 
    radial-gradient(circle at 20% 50%, rgba(26, 115, 232, 0.03) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(66, 133, 244, 0.03) 0%, transparent 50%);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  padding-top: 80px;
}

/* ===== Navigation Bar ===== */
.flex-navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  z-index: 1000;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.flex-nav-left {
  display: flex;
  align-items: center;
}

.flex-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text-primary);
  font-size: 18px;
  font-weight: 400;
}

.flex-logo-icon {
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.logo-avatar {
  width: 100%;
  height: 100%;
  transition: transform 0.3s ease-out;
  color: #1a73e8;
}

.flex-logo:hover .logo-avatar {
  transform: scale(1.05);
}

.flex-logo-icon svg {
  width: 100%;
  height: 100%;
}

.flex-logo-text {
  font-weight: 400;
  letter-spacing: -0.3px;
}

.flex-nav-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.flex-btn-outline {
  padding: 10px 20px;
  border: 1px solid var(--border-color);
  border-radius: 24px;
  color: var(--primary-blue);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
  background: transparent;
  cursor: pointer;
  font-family: inherit;
}

.flex-btn-outline:hover {
  background: var(--bg-light);
  border-color: var(--primary-blue);
}

.flex-btn-primary {
  padding: 10px 24px;
  background: var(--primary-blue);
  color: #ffffff;
  border: none;
  border-radius: 24px;
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
  cursor: pointer;
  font-family: inherit;
}

.flex-btn-primary:hover {
  background: var(--primary-blue-hover);
  box-shadow: 0 2px 8px rgba(26, 115, 232, 0.3);
}

/* ===== Main Content ===== */
.app-main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 32px 24px;
}

/* ===== Tabs ===== */
.app-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0;
}

.app-tab {
  padding: 12px 24px;
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--text-secondary);
  font-size: 16px;
  font-weight: 400;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
  position: relative;
  bottom: -1px;
}

.app-tab:hover {
  color: var(--text-primary);
  background: var(--bg-light);
}

.app-tab.active {
  color: var(--primary-blue);
  border-bottom-color: var(--primary-blue);
  font-weight: 500;
}

/* ===== Tab Content ===== */
.app-tab-content {
  display: none;
}

.app-tab-content.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ===== Sections ===== */
.app-section {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 32px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.app-section-title {
  font-size: 28px;
  font-weight: 400;
  color: var(--text-primary);
  margin-bottom: 8px;
  letter-spacing: -0.5px;
}

.app-section-description {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 24px;
  line-height: 1.6;
}

/* ===== Form Elements ===== */
.app-input-group {
  margin-bottom: 24px;
}

.app-input-group label {
  display: block;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.app-input,
.app-textarea {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 16px;
  font-family: inherit;
  color: var(--text-primary);
  background: var(--bg-white);
  transition: all 0.2s;
}

.app-input:focus,
.app-textarea:focus {
  outline: none;
  border-color: var(--primary-blue);
  box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.1);
}

.app-textarea {
  min-height: 120px;
  resize: vertical;
}

.app-file-input {
  width: 100%;
  padding: 8px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  font-size: 14px;
  font-family: inherit;
}

.app-input-group small {
  display: block;
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 4px;
}

/* ===== Actions ===== */
.app-actions {
  display: flex;
  gap: 12px;
  margin-top: 24px;
  flex-wrap: wrap;
}

/* ===== Word Cloud ===== */
.wordcloud-container {
  margin-top: 32px;
  padding: 32px;
  background: var(--bg-light);
  border-radius: 12px;
  min-height: 400px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 16px;
}

.wordcloud-word {
  display: inline-block;
  padding: 8px 16px;
  margin: 4px;
  border-radius: 20px;
  font-weight: 500;
  transition: transform 0.2s;
  cursor: pointer;
}

.wordcloud-word:hover {
  transform: scale(1.1);
}

/* ===== Multiple Choice ===== */
.mc-question-form {
  background: var(--bg-light);
  padding: 24px;
  border-radius: 8px;
  margin-bottom: 24px;
}

.mc-options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 16px;
}

.mc-questions-list {
  margin-top: 32px;
}

.mc-question-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
}

.mc-question-item h4 {
  font-size: 18px;
  font-weight: 500;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.mc-options-list {
  list-style: none;
  margin: 12px 0;
}

.mc-options-list li {
  padding: 8px 12px;
  margin: 4px 0;
  background: var(--bg-light);
  border-radius: 6px;
  color: var(--text-secondary);
}

.mc-options-list li.correct {
  background: rgba(52, 168, 83, 0.1);
  color: var(--success-green);
  font-weight: 500;
}

/* ===== Anagram ===== */
.anagram-form {
  background: var(--bg-light);
  padding: 24px;
  border-radius: 8px;
  margin-bottom: 24px;
}

.anagram-list {
  margin-top: 32px;
}

.anagram-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
}

.anagram-item h4 {
  font-size: 18px;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.anagram-scrambled {
  font-size: 24px;
  font-weight: 600;
  color: var(--primary-blue);
  letter-spacing: 4px;
  margin: 12px 0;
  font-family: 'Courier New', monospace;
}

.anagram-hint {
  font-size: 14px;
  color: var(--text-secondary);
  font-style: italic;
  margin-top: 8px;
}

/* ===== Exam Questions ===== */
.exam-form {
  background: var(--bg-light);
  padding: 24px;
  border-radius: 8px;
  margin-bottom: 24px;
}

.exam-questions-list {
  margin-top: 32px;
}

.exam-question-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
}

.exam-question-item h4 {
  font-size: 18px;
  font-weight: 500;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.exam-answer-form {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
}

.exam-answer-form input {
  margin-bottom: 12px;
}

.exam-answers-section {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 2px solid var(--border-color);
}

.exam-answers-list {
  margin-top: 24px;
}

.exam-answer-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 16px;
}

.exam-answer-item h5 {
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.exam-answer-item p {
  color: var(--text-secondary);
  margin: 4px 0;
}

/* ===== Activity Cards ===== */
.activity-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 24px;
  margin-top: 24px;
}

.activity-card {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 32px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.activity-card:hover {
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
  border-color: var(--primary-blue);
}

.activity-icon {
  width: 80px;
  height: 80px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  color: var(--text-primary);
}

.activity-name {
  font-size: 20px;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.activity-description {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ===== Modal ===== */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(4px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  animation: fadeIn 0.3s ease;
}

.modal-content {
  background: var(--bg-white);
  border-radius: 12px;
  padding: 32px;
  max-width: 700px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.2);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.modal-close {
  background: none;
  border: none;
  font-size: 32px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all 0.2s;
}

.modal-close:hover {
  background: var(--bg-light);
  color: var(--text-primary);
}

.mc-options-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 16px;
}

/* ===== Room Code Display ===== */
.room-code-display {
  text-align: center;
  padding: 24px;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  margin-bottom: 32px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

/* ===== Activities List ===== */
.activities-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.activity-item {
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 20px;
  transition: all 0.2s;
}

.activity-item:hover {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .flex-navbar {
    padding: 12px 16px;
    flex-wrap: wrap;
  }

  .flex-nav-right {
    gap: 8px;
  }

  .flex-btn-outline,
  .flex-btn-primary {
    padding: 8px 16px;
    font-size: 13px;
  }

  .app-main {
    padding: 24px 16px;
  }

  .app-tabs {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }

  .app-tab {
    padding: 10px 16px;
    font-size: 14px;
    white-space: nowrap;
  }

  .app-section {
    padding: 24px;
  }

  .mc-options {
    grid-template-columns: 1fr;
  }

  .app-actions {
    flex-direction: column;
  }

  .flex-btn-primary,
  .flex-btn-outline {
    width: 100%;
  }

  .activity-grid {
    grid-template-columns: 1fr;
  }

  .mc-options-grid {
    grid-template-columns: 1fr;
  }

  .modal-content {
    padding: 24px;
    max-height: 95vh;
  }
}