body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8f0 100%);
    scroll-behavior: smooth;
}
.login-container {
    max-width: 420px;
    margin: 0 auto;
}
.login-card {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
    transition: all 0.3s ease;
}
.login-card:hover {
    box-shadow: 0 8px 30px rgba(0,0,0,0.12);
}
.social-login-btn {
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}
.social-login-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}
.social-login-btn:active {
    transform: translateY(-1px);
}
.btn {
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}
.btn:active {
    transform: scale(0.98);
}
.btn::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 5px;
    height: 5px;
    background: rgba(255, 255, 255, 0.5);
    opacity: 0;
    border-radius: 100%;
    transform: scale(1, 1) translate(-50%);
    transform-origin: 50% 50%;
}
.btn:focus:not(:active)::after {
    animation: ripple 1s ease-out;
}
@keyframes ripple {
    0% {
        transform: scale(0, 0);
        opacity: 1;
    }
    20% {
        transform: scale(25, 25);
        opacity: 1;
    }
    100% {
        opacity: 0;
        transform: scale(40, 40);
    }
}
.form-control {
    transition: all 0.3s ease;
}
.form-control:focus {
    border-color: #3b82f6;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.25);
}
.form-control.error {
    border-color: #ef4444;
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.25);
}
.error-message {
    color: #ef4444;
    font-size: 0.75rem;
    margin-top: 0.25rem;
    display: none;
}
.loading {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 9999;
    justify-content: center;
    align-items: center;
}
.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}
.nav-link {
    position: relative;
    transition: all 0.3s ease;
}
.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: #2563eb;
    transition: width 0.3s ease;
}
.nav-link:hover::after {
    width: 100%;
}
.password-toggle {
    cursor: pointer;
    transition: color 0.2s ease;
}
.password-toggle:hover {
    color: #3b82f6;
}
.animate-fade-in {
    animation: fadeIn 0.5s ease-in-out;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}