/* Activity Competition App - Dark Theme */
:root {
  --bg-primary: #0B0F12;
  --bg-secondary: #121821;
  --bg-tertiary: #1A202C;
  --text-primary: #E6EAF0;
  --text-secondary: #A0AEC0;
  --text-muted: #718096;
  --accent-primary: #4FA800;
  --accent-secondary: #214700;
  --accent-tertiary: #68D391;
  --danger: #F56565;
  --warning: #ED8936;
  --success: #48BB78;
  --border: #2D3748;
  --shadow: rgba(0, 0, 0, 0.25);
  --shadow-lg: rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
}

/* Typography */
h1 { font-size: 2rem; font-weight: 700; line-height: 1.2; margin-bottom: 1rem; }
h2 { font-size: 1.5rem; font-weight: 600; line-height: 1.2; margin-bottom: 0.75rem; }
h3 { font-size: 1.25rem; font-weight: 600; line-height: 1.2; margin-bottom: 0.5rem; }
p { margin-bottom: 1rem; }
.text-sm { font-size: 0.875rem; }
.text-xs { font-size: 0.75rem; }
.text-muted { color: var(--text-muted); }
.text-secondary { color: var(--text-secondary); }

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem;
}

.grid {
  display: grid;
  gap: 1.5rem;
}

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

@media (min-width: 768px) {
  .grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
}

/* Cards */
.card {
  background-color: var(--bg-secondary);
  border-radius: 1rem;
  padding: 1.5rem;
  box-shadow: 0 4px 6px var(--shadow);
  border: 1px solid var(--border);
  transition: all 200ms ease;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px var(--shadow-lg);
}

.card-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 1rem;
  margin-bottom: 1rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  font-weight: 500;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all 200ms ease;
  font-size: 0.875rem;
  line-height: 1;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn:active {
  transform: translateY(0);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

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

.btn-primary:hover {
  background-color: var(--accent-tertiary);
}

.btn-secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background-color: var(--border);
}

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

.btn-danger:hover {
  background-color: #E53E3E;
}

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.75rem;
}

/* Forms */
.form-group {
  margin-bottom: 1rem;
}

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

.form-input,
.form-select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  font-size: 0.875rem;
  transition: all 200ms ease;
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(79, 168, 0, 0.1);
}

.form-input::placeholder {
  color: var(--text-muted);
}

/* Header */
.header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  margin-bottom: 2rem;
}

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

.header-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-primary);
}

.header-nav {
  display: flex;
  gap: 1rem;
  align-items: center;
}

/* Leaderboard */
.leaderboard-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem;
  border-radius: 0.5rem;
  background-color: var(--bg-tertiary);
  margin-bottom: 0.5rem;
  transition: all 200ms ease;
}

.leaderboard-item:hover {
  background-color: var(--border);
}

.leaderboard-rank {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.rank-badge {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.875rem;
}

.rank-1 {
  background: linear-gradient(135deg, #FFD700, #FFA500);
  color: #000;
}

.rank-2 {
  background: linear-gradient(135deg, #C0C0C0, #A0A0A0);
  color: #000;
}

.rank-3 {
  background: linear-gradient(135deg, #CD7F32, #8B4513);
  color: white;
}

.rank-other {
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
}

.user-avatar {
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 50%;
  background-color: var(--accent-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  margin-right: 1rem;
}

/* Activity History */
.history-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem;
  border-bottom: 1px solid var(--border);
}

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

.history-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.history-details {
  flex-grow: 1;
}

.history-activity {
  font-weight: 500;
  color: var(--text-primary);
}

.history-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

.history-points {
  text-align: right;
  font-weight: 600;
  color: var(--accent-primary);
}

/* Activity Form */
.activity-preview {
  background-color: var(--bg-tertiary);
  padding: 1rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border);
  margin: 1rem 0;
}

.preview-row {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.5rem;
}

.preview-row:last-child {
  margin-bottom: 0;
}

/* Login Page */
.login-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

.login-card {
  width: 100%;
  max-width: 400px;
  padding: 2rem;
}

/* Toast Notifications */
.toast {
  position: fixed;
  top: 1rem;
  right: 1rem;
  padding: 1rem 1.5rem;
  border-radius: 0.5rem;
  color: white;
  font-weight: 500;
  z-index: 1000;
  transform: translateX(100%);
  transition: transform 300ms ease;
}

.toast.show {
  transform: translateX(0);
}

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

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

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

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: all 200ms ease;
}

.modal-overlay.show {
  opacity: 1;
  visibility: visible;
}

.modal {
  background-color: var(--bg-secondary);
  border-radius: 1rem;
  padding: 2rem;
  max-width: 500px;
  width: 90%;
  transform: scale(0.9);
  transition: transform 200ms ease;
}

.modal-overlay.show .modal {
  transform: scale(1);
}

.modal-header {
  margin-bottom: 1.5rem;
}

.modal-footer {
  display: flex;
  gap: 1rem;
  justify-content: flex-end;
  margin-top: 2rem;
}

/* Loading States */
.loading {
  opacity: 0.6;
  pointer-events: none;
}

.spinner {
  width: 1rem;
  height: 1rem;
  border: 2px solid var(--border);
  border-top: 2px solid var(--accent-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0.5rem;
  }
  
  .header-content {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
  
  .header-nav {
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .leaderboard-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  
  .history-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  
  .modal {
    margin: 1rem;
    padding: 1.5rem;
  }
}

/* Utility Classes */
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.gap-2 { gap: 0.5rem; }
.gap-4 { gap: 1rem; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.w-full { width: 100%; }
.text-center { text-align: center; }
.hidden { display: none; }
.fade-in {
  animation: fadeIn 300ms ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}