.donation-subheading {
    font-size: clamp(1rem, 2.5vw, 1.25rem);
    color: rgba(255, 255, 255, 0.8);
    max-width: 700px;
    margin: -24px auto 40px;
    line-height: 1.6;
}

.donation-grid-wrapper {
    position: relative;
    padding: 2px; /* for border */
    border-radius: 18px;
    background: transparent;
    overflow: hidden;
}

.donation-grid-glow {
    position: absolute;
    top: 0;
    left: 0;
    width: 200px;
    height: 200px;
    background: radial-gradient(circle, var(--color-cyan) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
    z-index: 1;
    transform: translate(-50%, -50%); /* Center the glow on the cursor */
}

.donation-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    position: relative;
    z-index: 2;
    padding-top: 10px;
}

.donation-cell {
    position: relative;
    background: rgba(10, 10, 10, 0.5);
    border-radius: 16px;
    padding: clamp(20px, 3vw, 30px);
    text-align: center;
    border: 1px solid rgba(163, 220, 217, 0.1);
    cursor: pointer;
    transition: transform 0.3s ease, border-color 0.3s ease, background-color 0.3s ease;
}

.donation-cell input[type="radio"] {
    position: absolute;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.donation-cell .cell-content {
    transition: transform 0.3s ease;
}

.donation-cell:hover {
    transform: translateY(-8px);
    background-color: rgba(20, 22, 38, 0.7);
    border-color: rgba(163, 220, 217, 0.4);
}

.donation-cell input[type="radio"]:checked + .cell-content {
    transform: scale(0.95);
}

.donation-cell.selected {
    transform: translateY(-4px);
    border-color: var(--color-blue);
    background: rgba(51, 93, 225, 0.2);
    box-shadow: 0 0 20px -5px var(--color-blue);
}

.cell-icon {
    margin: 0 auto 16px;
    width: 44px;
    height: 44px;
    color: var(--color-cyan);
    transition: color 0.3s, transform 0.3s;
}

.donation-cell:hover .cell-icon {
    transform: scale(1.1);
}

.cell-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-white);
    margin-bottom: 6px;
}

.cell-amount {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-white), var(--color-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.checkout-section {
    border-top: 1px solid rgba(163, 220, 217, 0.2);
    margin-top: 40px;
    padding-top: 30px;
    display: flex;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap; 
}

.custom-amount-wrapper {
    flex: 1 1 300px; 
}

.donate-button-wrapper {
    flex: 1 1 200px; 
}

.custom-amount-input {
    width: 100%;
    background: rgba(10, 10, 10, 0.7);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: white;
    padding: 16px;
    border-radius: 12px;
    text-align: center;
    font-size: 1.1rem;
    transition: all 0.3s;
}

.custom-amount-input:focus {
    outline: none;
    border-color: var(--color-cyan);
    background: rgba(0, 0, 0, 0.3);
}

.custom-amount-input::placeholder {
    color: rgba(255, 255, 255, 0.5);
}

#donate-button {
     width: 100%;
     padding: 16px;
     font-size: 1.1rem;
}

#donate-button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    background: var(--color-dark-light);
}

#donate-button:disabled:hover {
    box-shadow: none;
    transform: none;
}

@media (max-width: 600px) {
    .checkout-section {
        flex-direction: column;
        align-items: stretch;
    }
}