/* Reset and general styles */
body {
    background: #f0f4f8;
    font-family: "Segoe UI", Tahoma, Arial, sans-serif;
    margin: 0;
    padding: 0;
}

/* Card container */
.lesson-card {
    max-width: 900px;
    margin: 40px auto;
    background: #ffffff;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
    border-top: 8px solid #0d6efd;
    position: relative;
}

/* Header */
.lesson-card h3 {
    font-weight: 800;
    margin-bottom: 30px;
    color: #0d6efd;
    font-size: 2rem;
    display: flex;
    align-items: center;
    gap: 12px;
}

/* Input groups with icons */
.input-group .input-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: #0d6efd;
    font-size: 1.2rem;
}

/* Form controls with padding for icons */
.input-group .form-control {
    padding-left: 38px; /* space for icon */
    border-radius: 10px;
    font-size: 1.1rem;
}

/* Labels */
.form-label {
    font-weight: 600;
    color: #333;
    font-size: 1.1rem;
    margin-bottom: 6px;
}

/* Buttons */
.btn-primary {
    background-color: #0d6efd;
    border: none;
    padding: 16px;
    font-size: 1.3rem;
    font-weight: 700;
    border-radius: 12px;
    transition: 0.3s;
    width: 100%;
}

.btn-primary:hover {
    background-color: #084298;
    transform: translateY(-2px);
}

/* Mobile adjustments */
@media (max-width: 768px) {
    .lesson-card {
        padding: 25px;
        margin: 20px;
    }

    .lesson-card h3 {
        font-size: 2.4rem;
    }

    .form-label {
        font-size: 1.3rem;
    }

    .form-control {
        font-size: 1.3rem;
        padding: 14px 12px