:root {
    --bg-color: #0d1117;
    --text-main: #ffffff;
    --text-sub: #8b949e;
    --card-bg: rgba(22, 27, 34, 0.7);
    --card-border: #30363d;
    --accent-tools: #3b82f6; 
    --accent-assets: #ec4899; 
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Noto Sans JP', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
    position: relative;
}


.bg-decoration {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    z-index: -1;
    opacity: 0.15;
}
.shape-1 {
    top: -10%;
    left: -10%;
    width: 50vw;
    height: 50vw;
    background: var(--accent-tools);
}
.shape-2 {
    bottom: -10%;
    right: -10%;
    width: 40vw;
    height: 40vw;
    background: var(--accent-assets);
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 4rem 2rem;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* ヘッダー周り */
.hero {
    text-align: center;
    margin-bottom: 4rem;
}

.title {
    font-family: 'Poppins', sans-serif;
    font-size: 3.5rem;
    font-weight: 900;
    letter-spacing: 2px;
    margin-bottom: 1rem;
}

.title span {
    background: linear-gradient(90deg, var(--accent-tools), var(--accent-assets));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    font-family: 'Poppins', sans-serif;
    font-size: 1.2rem;
    color: var(--text-sub);
    margin-bottom: 1.5rem;
}

.description {
    line-height: 1.6;
    color: #c9d1d9;
}


.cards-wrapper {
    display: grid;

    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    width: 100%;
}

.portal-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 2.5rem 2rem;
    text-decoration: none;
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    position: relative;
    overflow: hidden;
}


@media (hover: hover) {
    .portal-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
        border-color: rgba(255, 255, 255, 0.2);
    }
    .tools-card:hover { box-shadow: 0 10px 40px rgba(59, 130, 246, 0.15); }
    .assets-card:hover { box-shadow: 0 10px 40px rgba(236, 72, 153, 0.15); }
    .portal-card:hover .card-icon { transform: scale(1.1); }
    .portal-card:hover .card-arrow {
        transform: translateX(5px);
        color: var(--text-main);
    }
}

.card-icon {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    transition: transform 0.3s ease;
}

.tools-card .card-icon { color: var(--accent-tools); }
.assets-card .card-icon { color: var(--accent-assets); }

.card-content h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.card-content p {
    color: var(--text-sub);
    font-size: 0.95rem;
    line-height: 1.6;
}

.card-arrow {
    margin-top: 1.5rem;
    font-size: 1.2rem;
    color: var(--text-sub);
    transition: transform 0.3s ease, color 0.3s ease;
}


footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-sub);
    font-size: 0.85rem;
}


.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}


@media (max-width: 768px) {
    .title { 
        font-size: 2.2rem; 
    }
    .subtitle {
        font-size: 1rem;
    }
    .description {
        font-size: 0.9rem;
    }
    .hero {
        margin-bottom: 2.5rem;
    }
    .container { 
        padding: 2.5rem 1.5rem; 
    }
    .cards-wrapper {
        grid-template-columns: 1fr; 
        gap: 1.5rem; 
    }
    .portal-card { 
        padding: 2rem 1.5rem;
    }
    .card-icon {
        font-size: 3rem;
        margin-bottom: 1rem;
    }
    .bg-decoration {
        filter: blur(60px); 
    }
    .shape-1 {
        width: 80vw;
        height: 80vw;
    }
    .shape-2 {
        width: 70vw;
        height: 70vw;
    }
}