* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    background-color: #f8f9fa;
    color: #333;
    line-height: 1.6;
    overflow: hidden;
}

.zen-kaku-gothic-new-medium {
    font-family: "Zen Kaku Gothic New", sans-serif;
    font-weight: 500;
    font-style: normal;
}

.zen-kaku-gothic-new-bold {
    font-family: "Zen Kaku Gothic New", sans-serif;
    font-weight: 700;
    font-style: normal;
}

.biz-udpgothic-regular {
    font-family: "BIZ UDPGothic", sans-serif;
    font-weight: 400;
    font-style: normal;
}

.biz-udpgothic-bold {
    font-family: "BIZ UDPGothic", sans-serif;
    font-weight: 700;
    font-style: normal;
}

.header {
    width: 100%;
    height: 10vh;
    background-color: #ffffff;
    border-bottom: 1px solid #000000;
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: background-color 0.3s ease, backdrop-filter 0.3s ease;
}

.header-content {
    display: flex;
    align-items: center;
    padding: 0 20px;
    width: 100%;
    height: 100%;
}

.header-text {
    display: flex;
    align-items: center;
}

.logo {
    max-height: 80%;
    width: auto;
    margin-right: 15px;
    border-radius: 8px;
}

.name {
    font-family: "Zen Kaku Gothic New", sans-serif;
    font-weight: 700;
    font-style: normal;
    color: #004fb4;
    font-size: 50px;
    letter-spacing: 2px;
    line-height: 1;
    margin-right: 10px;
    margin-bottom: 10px;
}

.name-sub {
    font-family: "Zen Kaku Gothic New", sans-serif;
    font-weight: 500;
    font-style: normal;
    font-size: 30px;
    color: #004fb4;
    line-height: 1;
    margin-bottom: 5px;
}

.main-content {
    margin-top: 10vh;
    background-image: url('images/back1.png');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 90vh;
    padding: 0;
    transition: background-image 1s ease-in-out, background-size 1s ease-in-out;
}

.main-content.scrolled {
    background-image: url('images/back2.png');
}

.hero-section {
    text-align: center;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.hero-text {
    font-size: 50px;
    font-family: "BIZ UDPGothic", sans-serif;
    font-weight: bold;
    color: #ffffff;
    text-shadow: 0 0 12px rgba(0, 0, 0, 1);
    line-height: 1.5;
    text-align: center;
    white-space: pre-wrap;
    transition: opacity 0.5s ease-in-out;
}

.about-button {
    position: relative;
    overflow: hidden;
    padding: 10px 30px;
    font-size: 30px;
    font-weight: 700;
    color: #2a5daa;
    background-color: transparent;
    border: 1px solid #2a5daa;
    border-radius: 4px;
    cursor: pointer;
    font-family: "BIZ UDPGothic", sans-serif;
    transition: color 0.3s ease, opacity 0.5s ease-in-out;
}

.main-content.scrolled .about-button {
    color: white;
}

.about-button span {
    position: relative;
    z-index: 2;
}

.about-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 0%;
    height: 200%;
    background-color: #2a5daa;
    transform-origin: top left;
    transform: skew(-45deg);
    transition: width 0.5s ease;
    z-index: 1;
    pointer-events: none;
}

.about-button:hover::before {
    width: 150%;
}

.about-button:hover {
    color: white;
}

@media (min-width: 1920px) {
    .name {
        font-size: 80px; 
    }
    
    .name-sub {
        font-size: 48px;
    }
    
    .hero-text {
        font-size: 80px
    }
    
    .about-button {
        font-size: 48px;
        padding: 16px 48px; 
        border: 2px solid #2a5daa;
    }
}

@media (min-width: 2560px) {
    .name {
        font-size: 120px; 
    }
    
    .name-sub {
        font-size: 72px; 
    }
    
    .hero-text {
        font-size: 120px;
    }
    
    .about-button {
        font-size: 72px;
        padding: 24px 72px;
        border: 3px solid #2a5daa;
    }
}

@media (max-width: 768px) {
    .header {
        height: 8vh;
    }

    .main-content {
        margin-top: 8vh;
        height: 92vh;
        background-size: 250%;
        background-position: center center;
        transition: background-image 1s ease-in-out, background-size 1s ease-in-out;
    }

    .main-content.scrolled {
        background-size: 350%;
    }

    .name {
        font-size: 40px;
        letter-spacing: 1px;
    }

    .name-sub {
        font-size: 12px;
    }

    .logo {
        margin-right: 10px;
    }

    .hero-text {
        font-size: 2rem;
    }

    .hero-content {
        gap: 15px;
    }
}

@media (max-width: 480px) {
    .header-content {
        padding: 0 15px;
    }

    .name {
        font-size: 40px;
    }

    .name-sub {
        display: none;
    }

    .main-content {
        background-size: 300%;
        background-position: center center;
        transition: background-image 1s ease-in-out, background-size 1s ease-in-out;
    }

    .main-content.scrolled {
        background-size: 400%;
    }

    .hero-text {
        font-size: 1.5rem;
    }

    .hero-content {
        gap: 10px;
    }
}