@keyframes shine {
    0% {
        background-position: 200% 0;
        opacity: 0;
    }
    50% {
        opacity: 1;
    }
    100% {
        background-position: -200% 0;
        opacity: 0;
    }
}

.cta-button {
    display: inline-block;
    padding: 16px 38px;
    background: linear-gradient(45deg, #2C7D86, #4199A3);
    color: white;
    text-decoration: none;
    border-radius: 12px;
    margin: 20px 0;
    transition: all 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
    position: relative;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(44, 125, 134, 0.3);
    font-weight: 600;
    font-size: 1.05em;
    letter-spacing: 0.5px;
    text-transform: none;
    border: 2px solid rgba(255,255,255,0.15);
}

.cta-button:before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: radial-gradient(circle, rgba(255,255,255,0.2) 0%, rgba(255,255,255,0) 70%);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s ease-out, height 0.6s ease-out;
    z-index: 1;
}

.cta-button:after {
    content: '';
    position: absolute;
    top: -2px;
    left: -2px;
    right: -2px;
    bottom: -2px;
    background: linear-gradient(90deg, 
        rgba(255,255,255,0) 0%,
        rgba(255,255,255,0.2) 50%,
        rgba(255,255,255,0) 100%
    );
    background-size: 200% 100%;
    border-radius: 12px;
    z-index: -1;
    animation: shine 3s infinite;
    opacity: 0;
    transition: opacity 0.4s ease;
}

.cta-button:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 6px 20px rgba(44, 125, 134, 0.4);
    background: linear-gradient(45deg, #4199A3, #55B1BB);
    border-color: rgba(255,255,255,0.25);
}

.cta-button:hover:before {
    width: 250px;
    height: 250px;
}

.cta-button:hover:after {
    opacity: 1;
}

.cta-button:active {
    transform: translateY(1px) scale(0.98);
    box-shadow: 0 2px 8px rgba(44, 125, 134, 0.3);
}

/* スマートフォン向けの調整 */
@media (max-width: 768px) {
    .cta-button {
        padding: 14px 32px;
        font-size: 0.8em;
        letter-spacing: 0.3px;
    }
    
    .cta-button:hover {
        transform: translateY(-2px) scale(1.01);
    }
}