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

body{
    font-family: "MSゴシック", sans-serif;
    background: linear-gradient(135deg, #f0f8ff, #eaf6ff);
    color: #333;
    min-height: 100vh;
}

main{
    padding-top: 5em;
    max-width: 800px;
    margin:0 auto;
}

#first p{
    text-align: center;
}

.navi{
    background:rgba(30, 30, 30, 0.95);
    color: white;
    display: flex;
    width: 100vw;
    height: 4em;
    align-items: center;
    position: fixed;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.4);
    top: 0;
    padding: 0 1.5em
}


nav{
    display: flex;
    gap:1.5em;
}

nav a{
    line-height: 50px;
    color: #ccc;
    text-decoration: none;
    font-weight: 500;
}

a:hover{
    color: #00bfff;
    text-decoration: underline;
    text-shadow: 0 0 5px #00bfff88;
}

.logo{
    font-size: 1.3em;
    font-weight: bold;
    margin-right: auto;
    font-family: 'Segoe UI', sans-serif;
    color: #00bfff;
}

a:hover{
    color: #00bfff;
    text-decoration: underline;
    text-shadow: 0 0 5px #00bfff88;
}

main{
    padding-top: 6em;
    max-width: 960px;
    margin: 0 auto;
}

.introduce {
    display: flex;
    flex-direction: column;
    gap: 2em;
    margin-top: 2em;
}

.introduce > div {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid #444;
    border-radius: 12px;
    padding: 1.5em;
    box-shadow: 0 0 10px rgba(0, 191, 255, 0.2);
}

h1 {
    font-size: 2em;
    text-align: center;
    margin-bottom: 1em;
    color: #0077cc;
    text-shadow: 1px 1px 2px #ccc;
}

h2 {
    font-size: 1.5em;
    color: #222;
    margin-bottom: 0.5em;
    border-bottom: 2px solid #0077cc;
    padding-bottom: 0.3em;
}

.subtitle {
    font-style: italic;
    color: #555;
    margin-bottom: 1em;
    text-align: center;
}

.introduce img {
    width: 100%;
    border-radius: 8px;
    margin: 0.5em 0 1em;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    
}

.introduce p {
    line-height: 1.6em;
    margin-bottom: 0.5em;
    color: #444;
}

.s{
    text-align: right;
    font-size: 0.3em;
}

@media (max-width: 768px) {
    .introduce {
        padding: 0 1em;
    }
}

@media (max-width: 600px) {
    nav {
        gap: 0.5em;
    }

    nav a {
        font-size: 0.8em;
        padding: 0 0.3em;
    }

    .logo {
        font-size: 1em;
    }
}