:root {
    --primary: #2563eb;
    --border: #d1d5db;
    --bg: #f9fafb;
    --text: #111827;
}

* {
    box-sizing: border-box;
}

body {
    font-family: Inter, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 40px 16px;
}

.container {
    max-width: 980px;
    margin: auto;
    background: #ffffff;
    padding: 32px;
    border-radius: 10px;
    box-shadow: 0 10px 25px rgba(0,0,0,.08);
}

h2 {
    text-align: center;
    margin-bottom: 30px;
    font-size: 26px;
}

/* GRID */
.form-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}

/* RESPONSIVE */
@media (max-width: 900px) {
    .form-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 600px) {
    .form-grid {
        grid-template-columns: 1fr;
    }
}

/* FIELDS */
.field {
    display: flex;
    flex-direction: column;
}

.field.full {
    grid-column: span 3;
}

@media (max-width: 900px) {
    .field.full {
        grid-column: span 2;
    }
}

@media (max-width: 600px) {
    .field.full {
        grid-column: span 1;
    }
}

label {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 6px;
}

input,
select {
    padding: 10px 12px;
    border-radius: 6px;
    border: 1px solid var(--border);
    font-size: 14px;
    transition: border-color .15s, box-shadow .15s;
}

input:focus,
select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,.15);
}

/* BUTTON */
.submit-btn {
    margin-top: 30px;
    width: 100%;
    padding: 14px;
    background: var(--primary);
    color: #ffffff;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
}

.submit-btn:hover {
    background: #1e40af;
}

/* RESPONSE BOX */
.response-box {
    margin-top: 25px;
    padding: 15px;
    border-radius: 6px;
}

.success-box {
    background: #ecfdf5;
    color: #065f46;
}

.error-box {
    background: #fef2f2;
    color: #991b1b;
}

details {
    margin-top: 10px;
    font-size: 13px;
}