/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #f0f0f0; /* 明るいグレー */
    --secondary-color: #555; /* ダークグレー */
    --accent-color: #888; /* アクセント */
    --bg-dark: #1a1a1a;
    --bg-dark-subtle: #2a2a2a;
    --text-light: #f0f0f0;
    --text-dark: #333;
    --border-color: #444;
    --font-serif: 'Noto Serif JP', serif;
    --font-sans: 'Roboto', sans-serif;
    --spacing-lg: 80px;
    --spacing-md: 40px;
    --spacing-sm: 20px;
}

body {
    font-family: var(--font-sans);
    color: var(--text-light);
    background-color: var(--bg-dark);
    line-height: 1.6;
    overflow-x: hidden; /* 横スクロール防止 */
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.section-padding {
    padding: var(--spacing-lg) 0;
}

.section-title {
    font-family: var(--font-serif);
    font-size: 3em;
    text-align: center;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-color);
    letter-spacing: 0.05em;
}

.section-subtitle {
    font-size: 1.1em;
    text-align: center;
    color: var(--accent-color);
    margin-bottom: var(--spacing-md);
}

.bg-dark-subtle {
    background-color: var(--bg-dark-subtle);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border: 1px solid var(--primary-color);
    border-radius: 50px;
    text-decoration: none;
    font-family: var(--font-sans);
    font-weight: 500;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.btn-primary {
    background-color: transparent;
    color: var(--primary-color);
}

.btn-primary:hover {
    background-color: var(--primary-color);
    color: var(--bg-dark);
}

.btn-secondary {
    background: linear-gradient(45deg, #a0a0a0, #707070); /* Subtle gradient for secondary */
    border-color: transparent;
    color: var(--text-light);
    position: relative;
    overflow: hidden;
}

.btn-secondary::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.2);
    transform: skewX(-30deg);
    transition: all 0.4s ease;
}

.btn-secondary:hover::before {
    left: 100%;
}

/* Hero Section */
.hero-section {
    position: relative;
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    background: linear-gradient(135deg, var(--bg-dark), #000); /* Dark gradient background */
}

.hero-content {
    z-index: 2;
    text-align: center;
}

.logo-main {
    font-family: var(--font-serif);
    font-size: 8em;
    font-weight: 700;
    color: var(--primary-color);
    letter-spacing: 0.05em;
    opacity: 0; /* Animated with JS */
    transform: translateY(20px); /* Animated with JS */
}

.catchphrase {
    font-family: var(--font-serif);
    font-size: 2.2em;
    font-weight: 300;
    color: var(--primary-color);
    margin-top: var(--spacing-sm);
    opacity: 0; /* Animated with JS */
    transform: translateY(20px); /* Animated with JS */
}

.cta-buttons {
    margin-top: var(--spacing-md);
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    opacity: 0; /* Animated with JS */
    transform: translateY(20px); /* Animated with JS */
}

.particle-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    background-image: url('data:image/svg+xml;utf8,<svg width="100%" height="100%" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg"><circle cx="50" cy="50" r="1" fill="rgba(255,255,255,0.2)"/></svg>'); /* Simple SVG for particles */
    background-size: 10px 10px;
    animation: particle-flow 100s linear infinite;
    opacity: 0.5;
}

@keyframes particle-flow {
    0% { background-position: 0 0; }
    100% { background-position: 1000px 1000px; }
}


/* Philosophy Section */
.philosophy-text {
    font-family: var(--font-serif);
    font-size: 1.2em;
    max-width: 800px;
    margin: 0 auto var(--spacing-sm) auto;
    text-align: center;
    color: var(--accent-color);
    line-height: 1.8;
}

/* Services Section */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.service-card {
    background-color: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: var(--spacing-md);
    text-align: center;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 250px;
    position: relative;
    overflow: hidden;
}

.service-card::before { /* Subtle background animation */
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at center, rgba(255,255,255,0.05) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.service-card:hover::before {
    opacity: 1;
}

.service-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.4);
}

.service-icon {
    font-size: 3em;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
    transition: transform 0.3s ease;
}

.service-card:hover .service-icon {
    transform: scale(1.1);
}

.service-card h3 {
    font-family: var(--font-serif);
    font-size: 1.5em;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-color);
}

.service-card p {
    font-size: 0.95em;
    color: var(--accent-color);
}

/* Portfolio Section */
.portfolio-filters {
    text-align: center;
    margin-bottom: var(--spacing-md);
}

.filter-btn {
    background-color: transparent;
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
    padding: 8px 20px;
    margin: 0 5px;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: var(--font-sans);
    font-size: 0.9em;
}

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

.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.portfolio-item {
    position: relative;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    opacity: 0; /* Animated with JS */
    transform: translateY(20px); /* Animated with JS */
}

.portfolio-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.4s ease;
}

.portfolio-item:hover img {
    transform: scale(1.05);
}

.portfolio-item .overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    opacity: 0;
    transition: opacity 0.4s ease;
}

.portfolio-item:hover .overlay {
    opacity: 1;
}

.portfolio-item .overlay .project-name {
    font-family: var(--font-serif);
    font-size: 1.4em;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.portfolio-item .overlay .project-category {
    font-size: 0.9em;
    color: var(--accent-color);
}


/* Contact Section */
.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background-color: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: var(--spacing-md);
}

.form-group {
    margin-bottom: var(--spacing-sm);
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 1em;
    color: var(--primary-color);
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group textarea {
    width: 100%;
    padding: 12px;
    background-color: transparent;
    border: none;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-light);
    font-size: 1em;
    transition: border-color 0.3s ease, background-color 0.3s ease;
}

.form-group input[type="text"]:focus,
.form-group input[type="email"]:focus,
.form-group textarea:focus {
    outline: none;
    border-bottom-color: var(--primary-color);
    background-color: rgba(255, 255, 255, 0.05);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.submit-btn {
    width: auto;
    margin-top: var(--spacing-sm);
    display: block; /* Make it block to center if needed, or inline-block for flex parent */
    margin-left: auto;
    margin-right: auto;
}

/* Footer */
.footer {
    background-color: var(--bg-dark);
    color: var(--accent-color);
    text-align: center;
    padding: var(--spacing-sm) 0;
    border-top: 1px solid var(--border-color);
    font-size: 0.9em;
}

.footer .social-links {
    margin-top: 10px;
}

.footer .social-links a {
    color: var(--accent-color);
    font-size: 1.2em;
    margin: 0 10px;
    transition: color 0.3s ease;
}

.footer .social-links a:hover {
    color: var(--primary-color);
}

/* Scroll to Top Button */
.scroll-to-top-btn {
    position: fixed;
    bottom: var(--spacing-md);
    right: var(--spacing-md);
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.2em;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 1000;
    opacity: 0; /* Hidden by default, shown by JS */
    pointer-events: none; /* Disable interaction when hidden */
}

.scroll-to-top-btn.show {
    opacity: 1;
    pointer-events: auto;
}

.scroll-to-top-btn:hover {
    background-color: var(--primary-color);
    color: var(--bg-dark);
    transform: translateY(-3px);
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .section-title {
        font-size: 2.5em;
    }

    .catchphrase {
        font-size: 1.8em;
    }

    .logo-main {
        font-size: 6em;
    }

    .cta-buttons {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    .btn {
        width: 80%;
        margin: 0 auto;
    }

    .services-grid {
        grid-template-columns: 1fr;
    }

    .portfolio-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .section-title {
        font-size: 2em;
    }

    .catchphrase {
        font-size: 1.5em;
    }

    .logo-main {
        font-size: 4em;
    }

    .section-padding {
        padding: var(--spacing-md) 0;
    }
}