/* --- 基本設定と変数 --- */
:root {
    --primary-color: #1a202c; /* より深いチャコールグレー */
    --secondary-color: #4a90e2; /* 少し落ち着いたブルー */
    --light-bg-color: #f7fafc; /* 非常に薄いグレー */
    --text-color: #2d3748;
    --text-light-color: #a0aec0;
    --border-color: #e2e8f0;
    --container-width: 1100px;
    --font-sans: 'Noto Sans JP', sans-serif;
    --font-montserrat: 'Montserrat', sans-serif;
}

/* --- 基本スタイル --- */
*, *::before, *::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    margin: 0;
    color: var(--text-color);
    line-height: 1.8;
    background-color: #fff;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 24px;
}

.text-center {
    text-align: center;
}

/* --- ヘッダー --- */
.header {
    background-color: rgba(255, 255, 255, 0.8);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.site-title {
    font-family: var(--font-montserrat);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav ul {
    margin: 0;
    padding: 0;
    list-style: none;
    display: flex;
    gap: 0.5rem;
}

.nav a {
    font-family: var(--font-montserrat);
    text-decoration: none;
    color: #4a5568;
    padding: 0.5rem 1rem;
    transition: color 0.3s;
    font-weight: 700;
    border-radius: 6px;
}

.nav a:hover {
    color: var(--secondary-color);
    background-color: var(--light-bg-color);
}

/* --- ヒーローセクション --- */
#hero {
    background: linear-gradient(45deg, var(--primary-color), #2d3748);
    color: #fff;
    text-align: center;
    padding: 140px 24px;
}
.hero-title {
    font-family: var(--font-montserrat);
    font-size: 3.5rem;
    font-weight: 700;
    margin: 0 0 1rem;
    line-height: 1.2;
}
.hero-subtitle {
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text-light-color);
    max-width: 600px;
    margin: 0 auto;
}

/* --- 共通セクションスタイル & アニメーション --- */
.section {
    padding: 100px 0;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}
.section.is-visible {
    opacity: 1;
    transform: translateY(0);
}
.section-title {
    text-align: center;
    font-family: var(--font-montserrat);
    font-size: 2.75rem;
    font-weight: 700;
    margin: 0 0 60px;
    color: var(--primary-color);
}
.bg-light {
    background-color: var(--light-bg-color);
}

/* --- 実績・資格セクション --- */
.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.achievement-card {
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 32px;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    transition: transform 0.3s, box-shadow 0.3s;
}
.achievement-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
}
.achievement-date {
    font-size: 0.9rem;
    color: var(--text-light-color);
    margin: 0 0 10px;
}
.achievement-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
    color: var(--primary-color);
}

/* --- Profileセクション --- */
.profile-list {
    max-width: 800px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 150px 1fr;
    gap: 24px;
    font-size: 1.1rem;
}
.profile-list dt {
    font-weight: 700;
    color: var(--primary-color);
    text-align: right;
}
.profile-list dd {
    margin: 0;
}

/* --- Aboutセクション --- */
.about-content {
    max-width: 800px;
    margin: 0 auto;
    font-size: 1.1rem;
}
.about-content p {
    margin-bottom: 1.5em;
}

/* --- ボタン --- */
.button {
    display: inline-block;
    background-color: var(--secondary-color);
    color: #fff;
    padding: 14px 32px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.1rem;
    transition: background-color 0.3s, transform 0.3s;
    box-shadow: 0 4px 6px rgba(50, 50, 93, 0.11), 0 1px 3px rgba(0, 0, 0, 0.08);
}
.button:hover {
    background-color: #3b82f6; /* 少し明るい青 */
    text-decoration: none;
    transform: translateY(-3px);
    box-shadow: 0 7px 14px rgba(50, 50, 93, 0.1), 0 3px 6px rgba(0, 0, 0, 0.08);
}

/* --- フッター --- */
.footer {
    background-color: var(--primary-color);
    color: #fff;
    text-align: center;
    padding: 4rem 0;
}
.social-links {
    margin-bottom: 2rem;
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}
.social-links a {
    color: var(--text-light-color);
    transition: color 0.3s;
}
.social-links a:hover {
    color: #fff;
}
.social-links svg {
    width: 28px;
    height: 28px;
}
.copyright {
    color: #718096; /* 少し明るいグレー */
    font-size: 0.9rem;
}

/* --- レスポンシブ対応 --- */
@media (max-width: 768px) {
    .hero-title { font-size: 2.5rem; }
    .section-title { font-size: 2.25rem; }
    .header .container {
        flex-direction: column;
        gap: 1rem;
    }
    .profile-list {
        grid-template-columns: 1fr;
    }
    .profile-list dt {
        text-align: left;
        margin-bottom: 8px;
    }
}