:root {
  --primary: #2563eb;
  --primary-light: #60a5fa;
  --accent: #14b8a6;
  --bg: #f8fafc;
  --bg-dark: #18181b;
  --text: #1e293b;
  --text-light: #f1f5f9;
  --card: #fff;
  --card-dark: #23272f;
  --border: #e5e7eb;
  --border-dark: #2d3340;
  --transition: 0.3s cubic-bezier(.4,0,.2,1);
}

[data-theme="dark"] {
  --bg: var(--bg-dark);
  --text: var(--text-light);
  --card: var(--card-dark);
  --border: var(--border-dark);
}

html, body {
  margin: 0;
  padding: 0;
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background var(--transition), color var(--transition);
}

a { 
  color: var(--primary); 
  text-decoration: none; 
  transition: color var(--transition); 
}

a:hover { 
  color: var(--accent); 
}

.container { 
  max-width: 1100px; 
  margin: 0 auto; 
  padding: 0 1.5rem; 
}

header {
  display: flex; 
  align-items: center; 
  justify-content: space-between;
  padding: 2rem 0 1.5rem 0;
}

.logo {
  font-weight: 700; 
  font-size: 1.5rem; 
  letter-spacing: -1px;
  color: var(--primary);
}

.nav-links {
  display: flex; 
  gap: 2rem;
}

.nav-links a { 
  font-weight: 500; 
}

.theme-toggle {
  background: none; 
  border: none; 
  cursor: pointer; 
  font-size: 1.3rem;
  color: var(--text); 
  margin-left: 1.5rem; 
  transition: color var(--transition);
}

.sticky-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg);
  transition: background var(--transition);
  box-shadow: 0 2px 8px 0 rgba(30,41,59,0.04);
}

.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  margin-left: 1rem;
  z-index: 110;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 3px;
  margin: 3px 0;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.3s;
}

/* Login Form */
.login-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - 120px);
  padding: 2rem 0;
}

.login-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 1rem;
  padding: 2.5rem;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 4px 24px 0 rgba(30,41,59,0.08);
  transition: background var(--transition), border var(--transition);
}

.login-header {
  text-align: center;
  margin-bottom: 2rem;
}

.login-title {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.login-subtitle {
  color: #64748b;
  font-size: 1rem;
}

[data-theme="dark"] .login-subtitle {
  color: #cbd5e1;
}

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

.form-label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text);
  font-size: 0.95rem;
}

.form-input {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  font-size: 1rem;
  font-family: inherit;
  background: var(--bg);
  color: var(--text);
  transition: border var(--transition), background var(--transition), color var(--transition);
  box-sizing: border-box;
}

.form-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.form-input::placeholder {
  color: #94a3b8;
}

[data-theme="dark"] .form-input::placeholder {
  color: #64748b;
}

.form-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
}

.checkbox-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.checkbox-group input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
}

.checkbox-group label {
  font-size: 0.9rem;
  color: var(--text);
  cursor: pointer;
}

.forgot-link {
  font-size: 0.9rem;
  color: var(--primary);
  text-decoration: none;
}

.forgot-link:hover {
  color: var(--accent);
}

.login-btn {
  width: 100%;
  padding: 0.85rem 1.5rem;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition);
  margin-bottom: 1.5rem;
}

.login-btn:hover {
  background: var(--accent);
}

.login-btn:disabled {
  background: #94a3b8;
  cursor: not-allowed;
}

.divider {
  display: flex;
  align-items: center;
  margin: 1.5rem 0;
  color: #64748b;
  font-size: 0.9rem;
}

[data-theme="dark"] .divider {
  color: #94a3b8;
}

.divider::before,
.divider::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
}

.divider span {
  padding: 0 1rem;
}

.social-btn {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background: var(--card);
  color: var(--text);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition), border var(--transition);
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.social-btn:hover {
  background: var(--bg);
  border-color: var(--primary);
}

.signup-link {
  text-align: center;
  margin-top: 1.5rem;
  color: #64748b;
  font-size: 0.95rem;
}

[data-theme="dark"] .signup-link {
  color: #cbd5e1;
}

.signup-link a {
  font-weight: 600;
}

.error-message {
  background: #fef2f2;
  color: #dc2626;
  padding: 0.75rem 1rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  margin-bottom: 1rem;
  border: 1px solid #fecaca;
}

[data-theme="dark"] .error-message {
  background: #450a0a;
  color: #fca5a5;
  border-color: #7f1d1d;
}

.success-message {
  background: #f0fdf4;
  color: #16a34a;
  padding: 0.75rem 1rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  margin-bottom: 1rem;
  border: 1px solid #bbf7d0;
}

[data-theme="dark"] .success-message {
  background: #052e16;
  color: #86efac;
  border-color: #166534;
}

.verification-link {
  text-align: center;
  margin-top: 1rem;
  color: #64748b;
  font-size: 0.9rem;
}

[data-theme="dark"] .verification-link {
  color: #cbd5e1;
}

.verification-link a {
  font-weight: 600;
}

/* Mobile Responsive */
@media (max-width: 900px) {
  .nav-links {
    position: fixed;
    top: 70px;
    right: 0;
    background: var(--card);
    flex-direction: column;
    align-items: flex-start;
    gap: 1.5rem;
    padding: 2rem 2rem 2rem 1.5rem;
    box-shadow: 0 4px 24px 0 rgba(30,41,59,0.10);
    border-radius: 0 0 0.7rem 0.7rem;
    transform: translateY(-120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.3s, opacity 0.3s;
    min-width: 60vw;
  }
  
  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  
  .hamburger {
    display: flex;
  }
  
  .logo {
    z-index: 120;
  }
  
  .theme-toggle {
    z-index: 120;
    margin-left: 0.5rem;
  }
  
  .container { 
    padding: 0 0.5rem; 
  }
}

@media (max-width: 600px) {
  .nav-links {
    top: 60px;
    padding: 1.2rem 1.2rem 1.2rem 1rem;
    min-width: 80vw;
  }
  
  .login-card {
    padding: 2rem 1.5rem;
    margin: 0 1rem;
  }
}