:root {
    --background: 0 0% 100%;
    --foreground: 222.2 84% 4.9%;
    --primary: 221.2 83.2% 53.3%;
    --primary-foreground: 210 40% 98%;
    --border: 214.3 31.8% 91.4%;
    --input: 214.3 31.8% 91.4%;
    --ring: 221.2 83.2% 53.3%;
    --radius: 0.5rem;
}
body { 
    font-family: Inter, -apple-system, sans-serif;
    background-color: #f8fafc;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    margin: 0;
}
.card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    width: 100%;
    max-width: 400px;
    border: 1px solid var(--border);
}
h1 { 
    font-size: 1.5rem; 
    font-weight: 600; 
    margin-bottom: 1.5rem; 
    text-align: center; 
    color: var(--foreground); }
.form-group { 
    margin-bottom: 1rem; 
}
label { 
    display: block; 
    font-size: 0.875rem; 
    font-weight: 500; 
    margin-bottom: 0.5rem; 
}
input {
    width: 100%;
    padding: 0.625rem;
    border: 1px solid var(--input);
    border-radius: var(--radius);
    box-sizing: border-box;
    font-size: 0.875rem;
}
input:focus { 
    outline: none; 
    border-color: var(--ring); 
    ring: 2px solid var(--ring); 
}
button {
    width: 100%;
    padding: 0.625rem;
    background-color: #2563eb;
    color: white;
    border: none;
    border-radius: var(--radius);
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s;
}
button:hover { 
    background-color: #1d4ed8;  
}
.error { 
    color: #ef4444; 
    font-size: 0.875rem; 
    margin-top: 1rem; 
    text-align: center; 
    display: none; 
}