:root {
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --secondary: #8b5cf6;
  --bg: #0f172a;
  --bg-light: #1e293b;
  --bg-card: #334155;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --border: #475569;
  --success: #10b981;
  --error: #ef4444;
}

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

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

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

header {
  background: var(--bg-light);
  border-bottom: 1px solid var(--border);
  padding: 20px 0;
  margin-bottom: 40px;
}

header h1 {
  font-size: 2rem;
  margin-bottom: 5px;
}

.tagline {
  color: var(--text-muted);
  margin-bottom: 15px;
}

nav {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

nav button {
  padding: 8px 16px;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
}

nav button:hover {
  background: var(--bg-card);
  border-color: var(--primary);
}

.view {
  animation: fadeIn 0.3s;
}

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

.hero {
  text-align: center;
  padding: 60px 20px;
}

.hero h2 {
  font-size: 2.5rem;
  margin-bottom: 15px;
}

.hero p {
  color: var(--text-muted);
  font-size: 1.2rem;
  max-width: 600px;
  margin: 0 auto 30px;
}

.cta-buttons {
  display: flex;
  gap: 15px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn-primary, .btn-secondary, .btn-back {
  padding: 12px 24px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s;
}

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

.btn-primary:hover {
  background: var(--primary-dark);
}

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

.btn-secondary:hover {
  background: var(--bg-card);
}

.btn-back {
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  margin-bottom: 20px;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-top: 60px;
}

.feature-card {
  background: var(--bg-light);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border);
}

.feature-card h3 {
  font-size: 1.3rem;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-muted);
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin-top: 20px;
}

.user-card, .group-card {
  background: var(--bg-light);
  padding: 20px;
  border-radius: 12px;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.2s;
}

.user-card:hover, .group-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.user-card h3, .group-card h3 {
  margin-bottom: 8px;
}

.user-card .email, .group-card .members {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 10px;
}

.skills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.skill-tag {
  background: var(--bg-card);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.85rem;
  border: 1px solid var(--border);
}

.form-card {
  background: var(--bg-light);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border);
  max-width: 600px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  margin-bottom: 8px;
  color: var(--text-muted);
}

.form-group input, .form-group textarea {
  width: 100%;
  padding: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 1rem;
}

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

.detail-card {
  background: var(--bg-light);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border);
  margin-bottom: 30px;
}

.detail-card h2 {
  margin-bottom: 10px;
}

.endorsements {
  margin-top: 30px;
}

.endorsement {
  background: var(--bg-card);
  padding: 15px;
  border-radius: 8px;
  margin-bottom: 10px;
  border-left: 3px solid var(--primary);
}

.endorsement-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 5px;
}

.endorser {
  font-weight: 600;
}

.endorsement-skill {
  color: var(--primary);
  font-weight: 500;
}

.endorsement-date {
  color: var(--text-muted);
  font-size: 0.85rem;
}

#endorsement-section {
  background: var(--bg-light);
  padding: 30px;
  border-radius: 12px;
  border: 1px solid var(--border);
}

#endorsement-form input,
#endorsement-form textarea {
  width: 100%;
  padding: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  margin-bottom: 12px;
  font-size: 1rem;
}

.view-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.form-actions {
  display: flex;
  gap: 10px;
  margin-top: 15px;
}

footer {
  margin-top: 80px;
  padding: 30px 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
}

@media (max-width: 768px) {
  .hero h2 {
    font-size: 2rem;
  }
  
  .cards-grid {
    grid-template-columns: 1fr;
  }
}