:root {
    --sd-primary: #6366f1;
    --sd-primary-dark: #4f46e5;
    --sd-bg: #f8fafc;
    --sd-text: #0f172a;
}
body { 
    font-family: 'Inter', 'Noto Sans SC', sans-serif; 
    background-color: var(--sd-bg);
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.1) 0, transparent 50%), 
        radial-gradient(at 50% 0%, rgba(139, 92, 246, 0.1) 0, transparent 50%), 
        radial-gradient(at 100% 0%, rgba(217, 70, 239, 0.1) 0, transparent 50%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0;
    padding: 20px;
    -webkit-font-smoothing: antialiased;
}
.login-card {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 20px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    overflow: hidden;
    width: 100%;
    max-width: 400px;
    padding: 1.5rem;
}
.login-header {
    text-align: center;
    margin-bottom: 1.5rem;
}
.login-header h2 {
    font-weight: 800;
    color: var(--sd-text);
    letter-spacing: -1px;
    margin-bottom: 8px;
    font-size: 1.75rem;
}
.login-header p { 
    color: #64748b; 
    font-size: 0.95rem; 
    font-weight: 500;
}
.login-body { 
    padding: 0; 
}
.form-label {
    font-weight: 600;
    color: #475569;
    margin-bottom: 0.5rem;
}
.form-control {
    border-radius: 10px;
    padding: 0.6rem 0.75rem;
    border: 1px solid #e2e8f0;
    background: #f8fafc;
    font-size: 0.9rem;
    transition: all 0.2s;
}
.form-control-sm,
.input-group-sm > .form-control,
.input-group-sm > .input-group-text,
.input-group-sm > .btn {
    height: 36px !important;
    padding: 0 0.75rem !important;
    font-size: 0.85rem !important;
    border-radius: 8px !important;
}
.input-group-sm > .input-group-text {
    padding: 0 !important;
    overflow: hidden;
}
.input-group-sm > .input-group-text img {
    height: 34px !important; /* 36px - 2px borders */
}
.form-control:focus {
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
    border-color: var(--sd-primary);
    background: #fff;
    outline: none;
}
.btn-login {
    background: var(--sd-primary);
    border: none;
    border-radius: 12px;
    padding: 0.75rem;
    font-weight: 700;
    font-size: 1rem;
    color: white;
    transition: all 0.2s;
    margin-top: 1rem;
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.25);
}
.btn-login:hover {
    background: var(--sd-primary-dark);
    box-shadow: 0 6px 15px rgba(99, 102, 241, 0.35);
    transform: translateY(-1px);
}
.btn-login:active {
    transform: translateY(0);
}
.error-shake {
    animation: shake 0.5s cubic-bezier(.36,.07,.19,.97) both;
}
@keyframes shake {
    10%, 90% { transform: translate3d(-1px, 0, 0); }
    20%, 80% { transform: translate3d(2px, 0, 0); }
    30%, 50%, 70% { transform: translate3d(-4px, 0, 0); }
    40%, 60% { transform: translate3d(4px, 0, 0); }
}