:root {
    --primary-color: #3498db;
    --secondary-color: #2980b9;
    --accent-color: #e74c3c;
    --text-color: #333;
    --light-text: #777;
    --background: #f9f9f9;
    --card-bg: #ffffff;
    --animation-speed: 0.3s;
    --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
}

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

body {
    font-family: 'Noto Sans JP', 'Poppins', sans-serif;
    background-color: var(--background);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ローダー */
.loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--background);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 0.5s ease-out, visibility 0.5s;
}

.loader.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader-icon {
    width: 80px;
    height: 80px;
    animation: rotate 2s linear infinite;
}

.loader-icon circle {
    stroke-dasharray: 150;
    stroke-dashoffset: 150;
    animation: dash 1.5s ease-in-out infinite;
}

@keyframes rotate {
    100% {
        transform: rotate(360deg);
    }
}

@keyframes dash {
    0% {
        stroke-dashoffset: 150;
    }
    50% {
        stroke-dashoffset: 30;
    }
    100% {
        stroke-dashoffset: 150;
    }
}

/* ヘッダー */
header {
    background-color: rgba(255, 255, 255, 0.95);
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

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

.site-title {
    font-size: 28px;
    font-weight: 700;
}

.site-title-link {
    text-decoration: none;
    color: inherit;
    display: block;
    transition: opacity 0.2s ease;
}

.site-title-link:hover {
    opacity: 0.8;
}

.logo {
    width: 180px;
    height: 40px;
}

.logo text {
    fill: var(--text-color);
}

nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    padding: 5px 0;
    position: relative;
    transition: color var(--animation-speed);
}

nav a:hover, nav a.active {
    color: var(--primary-color);
}

nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width var(--animation-speed);
}

nav a:hover::after, nav a.active::after {
    width: 100%;
}

/* ヒーローセクション */
.hero {
    padding: 50px 0 30px;
    position: relative;
    overflow: hidden;
    text-align: center;
}

.hero-title {
    font-size: 2.4rem;
    margin-bottom: 15px;
    font-weight: 700;
    color: var(--text-color);
    animation: fadeInUp 1s;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--light-text);
    margin-bottom: 0;
    max-width: 800px;
    margin: 0 auto;
    animation: fadeInUp 1s 0.2s backwards;
}

/* プロジェクトセクション */
.projects {
    padding: 60px 0 80px;
    background-color: #fff;
}

.section-title {
    font-size: 2.5rem;
    margin-bottom: 40px;
    text-align: center;
    font-weight: 700;
}

.filter-container {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 40px;
}

.filter-btn {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 8px 20px;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 500;
    font-size: 1rem;
    transition: all var(--animation-speed);
}

.filter-btn:hover, .filter-btn.active {
    background-color: var(--primary-color);
    color: white;
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 40px;
}

.project-card {
    background-color: var(--card-bg);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform var(--animation-speed);
    animation: fadeInUp 0.6s backwards;
    display: block;
    text-decoration: none;
    color: var(--text-color);
}

.project-card:hover {
    transform: translateY(-10px);
}

.project-thumbnail {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.project-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s;
}

.project-card:hover .project-thumbnail img {
    transform: scale(1.05);
}

.project-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    transition: opacity var(--animation-speed);
}

.project-card:hover .project-overlay {
    opacity: 1;
}

.view-btn {
    padding: 8px 15px;
    background-color: var(--primary-color);
    color: white;
    border-radius: 4px;
    font-weight: 500;
    transition: background-color var(--animation-speed);
}

.view-btn:hover {
    background-color: var(--secondary-color);
}

.project-info {
    padding: 20px;
}

.project-title {
    font-size: 1.3rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.project-description {
    color: var(--light-text);
    margin-bottom: 15px;
    font-size: 0.95rem;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 10px;
}

.project-tag {
    background-color: rgba(52, 152, 219, 0.1);
    color: var(--primary-color);
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
}

.project-date {
    font-size: 0.8rem;
    color: var(--light-text);
}

/* フッター */
footer {
    background-color: #222;
    color: #fff;
    padding: 40px 0;
}

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

.social-links {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
    margin-top: 10px;
}

.social-icon-link {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    color: #fff;
    font-size: 18px;
    transition: transform var(--animation-speed), background-color var(--animation-speed);
    text-decoration: none;
}

.social-icon-link:hover {
    transform: scale(1.1);
    background-color: rgba(255, 255, 255, 0.2);
}

.social-icon {
    width: 24px;
    height: 24px;
    fill: #fff;
}

/* アニメーション */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* レスポンシブ対応 */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .projects-grid {
        grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    }
}

@media (max-width: 480px) {
    header .container {
        flex-direction: column;
        gap: 15px;
    }
    
    nav ul {
        gap: 15px;
    }
    
    .hero {
        padding: 50px 0 30px;
    }
    
    .section-title {
        font-size: 2rem;
    }
}