```css
/* =========================================================
   ENROLLMENT FORM
   Clean & Professional Responsive Design
   ========================================================= */

/* ---------- Container ---------- */

.enrollment-container {
    width: 100%;
    max-width: 100%;
    padding: 50px 20px;
    box-sizing: border-box;
}


/* ---------- Form Card ---------- */

.enrollment-form-wrapper {
    width: 100%;
    max-width: 520px;
    margin: 0 auto;
    padding: 38px;
    background: #ffffff;
    border: 1px solid #e8e8e8;
    border-radius: 14px;
    box-shadow: 0 10px 35px rgba(0, 0, 0, 0.08);
    box-sizing: border-box;
}


/* ---------- Heading ---------- */

.enrollment-form-wrapper h2 {
    margin: 0;
    text-align: center;
    font-size: 30px;
    font-weight: 700;
    line-height: 1.3;
    color: #1f2937;
}


/* ---------- Subtitle ---------- */

.form-subtitle {
    margin: 10px 0 30px;
    text-align: center;
    font-size: 15px;
    line-height: 1.6;
    color: #6b7280;
}


/* ---------- Form Group ---------- */

.form-group {
    margin-bottom: 20px;
}


/* ---------- Labels ---------- */

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    font-weight: 600;
    line-height: 1.4;
    color: #374151;
}

.form-group label span {
    margin-left: 2px;
    color: #dc2626;
}

.form-group label small {
    font-size: 12px;
    font-weight: 400;
    color: #9ca3af;
}


/* ---------- Form Controls ---------- */

.form-group input,
.form-group select,
.form-group textarea {
    display: block;
    width: 100%;
    padding: 13px 14px;
    margin: 0;

    border: 1px solid #d1d5db;
    border-radius: 8px;

    background-color: #ffffff;
    color: #1f2937;

    font-family: inherit;
    font-size: 15px;
    line-height: 1.5;

    outline: none;
    box-sizing: border-box;

    transition:
        border-color 0.2s ease,
        box-shadow 0.2s ease,
        background-color 0.2s ease;
}


/* ---------- Placeholder ---------- */

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: #9ca3af;
    opacity: 1;
}


/* ---------- Select ---------- */

.form-group select {
    cursor: pointer;
    appearance: auto;
}


/* ---------- Textarea ---------- */

.form-group textarea {
    min-height: 105px;
    resize: vertical;
}


/* ---------- Focus State ---------- */

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    border-color: #2563eb;
    background-color: #ffffff;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.10);
}


/* ---------- Hover State ---------- */

.form-group input:hover,
.form-group select:hover,
.form-group textarea:hover {
    border-color: #9ca3af;
}


/* ---------- Submit Button ---------- */

.enroll-button {
    display: block;
    width: 100%;

    padding: 14px 20px;
    margin-top: 8px;

    border: none;
    border-radius: 8px;

    background: #2563eb;
    color: #ffffff;

    font-family: inherit;
    font-size: 16px;
    font-weight: 600;
    line-height: 1.5;

    cursor: pointer;

    transition:
        background-color 0.2s ease,
        box-shadow 0.2s ease,
        transform 0.2s ease;
}


/* ---------- Button Hover ---------- */

.enroll-button:hover {
    background: #1d4ed8;
    box-shadow: 0 5px 15px rgba(37, 99, 235, 0.20);
}


/* ---------- Button Active ---------- */

.enroll-button:active {
    transform: translateY(1px);
}


/* ---------- Button Focus ---------- */

.enroll-button:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.25);
    outline-offset: 2px;
}


/* ---------- Bottom Note ---------- */

.form-note {
    margin: 18px 0 0;

    text-align: center;

    font-size: 12px;
    line-height: 1.6;

    color: #9ca3af;
}


/* ---------- Validation ---------- */

.form-group input:invalid:not(:placeholder-shown),
.form-group select:invalid:not(:focus),
.form-group textarea:invalid:not(:placeholder-shown) {
    border-color: #d1d5db;
}


/* ---------- Disabled Button ---------- */

.enroll-button:disabled {
    cursor: not-allowed;
    opacity: 0.65;
    box-shadow: none;
}


/* =========================================================
   RESPONSIVE DESIGN
   ========================================================= */


/* ---------- Tablet ---------- */

@media (max-width: 768px) {

    .enrollment-container {
        padding: 35px 18px;
    }

    .enrollment-form-wrapper {
        max-width: 520px;
        padding: 32px;
    }
}


/* ---------- Mobile ---------- */

@media (max-width: 480px) {

    .enrollment-container {
        padding: 25px 15px;
    }

    .enrollment-form-wrapper {
        padding: 25px 20px;
        border-radius: 12px;
    }

    .enrollment-form-wrapper h2 {
        font-size: 26px;
    }

    .form-subtitle {
        margin-bottom: 25px;
        font-size: 14px;
    }

    .form-group {
        margin-bottom: 18px;
    }

    .form-group input,
    .form-group select,
    .form-group textarea {
        padding: 12px 13px;
        font-size: 14px;
    }

    .enroll-button {
        padding: 13px 18px;
        font-size: 15px;
    }
}


/* ---------- Small Mobile ---------- */

@media (max-width: 360px) {

    .enrollment-form-wrapper {
        padding: 22px 16px;
    }

    .enrollment-form-wrapper h2 {
        font-size: 24px;
    }
}
```