/* --- ヒーローセクション（トップ画像） --- */
.hero {
    margin: 40px 0 60px;
    position: relative;
    height: 400px;
    overflow: hidden;
    background-color: var(--gray-light);
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--hero-fallback-gradient);
    z-index: 1;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.hero.hero-loaded::before {
    opacity: 0;
}

.hero.hero-fallback::before {
    opacity: 1;
}

.hero img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 2;
    filter:
        brightness(calc(var(--hero-image-brightness) + var(--viewport-brightness-adjustment)))
        contrast(var(--hero-image-contrast))
        saturate(var(--hero-image-saturation))
        grayscale(var(--hero-grayscale));
    opacity: 0;
    transition: opacity 0.3s ease, filter 0.3s ease;
}

.hero.hero-loaded img {
    opacity: 1;
}

.hero.hero-fallback img {
    opacity: 0;
}

.hero::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        180deg,
        rgba(0, 0, 0, calc(var(--hero-overlay-opacity) * 0.4 * var(--viewport-overlay-multiplier))) 0%,
        rgba(0, 0, 0, calc(var(--hero-overlay-opacity) * 0.8 * var(--viewport-overlay-multiplier))) 50%,
        rgba(0, 0, 0, calc(var(--hero-overlay-opacity) * 1.0 * var(--viewport-overlay-multiplier))) 100%
    );
    z-index: 3;
    pointer-events: none;
    -webkit-backdrop-filter: blur(var(--hero-backdrop-blur));
    backdrop-filter: blur(var(--hero-backdrop-blur));
}

.hero-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #fff;
    text-align: center;
    z-index: 4;
    text-shadow:
        var(--hero-text-shadow),
        0 0 40px rgba(0, 0, 0, 0.6),
        0 4px 8px rgba(0, 0, 0, 0.4);
    opacity: 1;
    -webkit-backdrop-filter: blur(1px);
    backdrop-filter: blur(1px);
}

.hero-text h2 {
    font-family: var(--font-en);
    font-size: 3rem;
    font-weight: 500;
    letter-spacing: 0.15em;
    color: #ffffff;
    text-shadow:
        var(--hero-text-shadow),
        0 0 60px rgba(0, 0, 0, 0.8),
        0 6px 12px rgba(0, 0, 0, 0.6),
        0 2px 4px rgba(0, 0, 0, 0.9);
    -webkit-text-stroke: 1px rgba(0, 0, 0, 0.3);
}