/* Basic Reset & Theme */
body {
    background-color: #0f172a; /* Dark slate */
    color: #f8fafc;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}

.form-container {
    background-color: #1e293b;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
    width: 100%;
    max-width: 400px;
}

h2 { color: #38bdf8; margin-top: 0; }

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

label { display: block; margin-bottom: 0.5rem; font-size: 0.9rem; }

input {
    width: 100%;
    padding: 10px;
    border: 1px solid #334155;
    border-radius: 4px;
    background: #0f172a;
    color: white;
    box-sizing: border-box; /* Ensures padding doesn't affect width */
}

/* Visual Feedback for Validation */
input:focus {
    outline: none;
    border-color: #38bdf8;
}

input:invalid:not(:placeholder-shown) {
    border-color: #ef4444; /* Red border for errors */
}

input:valid:not(:placeholder-shown) {
    border-color: #22c55e; /* Green border for success */
}

.btn-submit {
    width: 100%;
    padding: 12px;
    background-color: #38bdf8;
    border: none;
    border-radius: 4px;
    color: #0f172a;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.3s;
}

.btn-submit:hover { background-color: #0ea5e9; }