/* ==========================================================================
   Variables
   ========================================================================== */
:root {
    /* Colors */
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-primary: #2c3e50;
    --text-secondary: #7f8c8d;
    --text-light: #bdc3c7;
    --bg-white: #ffffff;
    --bg-light: #f8f9fa;
    --bg-dark: #2c3e50;
    --border-light: #e9ecef;
    --shadow-light: rgba(0, 0, 0, 0.1);
    --shadow-medium: rgba(0, 0, 0, 0.15);
    
    /* Typography */
    --font-primary: 'Inter', 'Noto Sans JP', sans-serif;
    --font-japanese: 'Noto Sans JP', sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* Container width */
    --container-width: 1200px;
    --container-padding: 1rem;
}

/* ==========================================================================
   Base Styles
   ========================================================================== */
* {
    box-sizing: border-box;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-white);
    overflow-x: hidden;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-fast);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    outline: none;
    transition: var(--transition-fast);
}

/* ==========================================================================
   Utility Classes
   ========================================================================== */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

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

.section--light {
    background-color: var(--bg-light);
}

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

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

.text-light {
    color: var(--text-light);
}

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

/* ==========================================================================
   Typography
   ========================================================================== */
.heading-primary {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.heading-secondary {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.heading-tertiary {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 500;
    line-height: 1.4;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.text-large {
    font-size: 1.25rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px var(--shadow-light);
    z-index: 1000;
    transition: var(--transition-medium);
}

.nav__container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav__logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    transition: var(--transition-fast);
}

.nav__logo:hover {
    color: var(--secondary-color);
}

.nav__list {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav__link {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    font-weight: 500;
    color: var(--text-primary);
    transition: var(--transition-fast);
}

.nav__link:hover,
.nav__link--active {
    background-color: var(--secondary-color);
    color: var(--bg-white);
}

.nav__link i {
    font-size: 0.9rem;
}

.nav__toggle {
    display: none;
    font-size: 1.5rem;
    color: var(--primary-color);
    cursor: pointer;
}

/* ==========================================================================
   Main Content
   ========================================================================== */
.main {
    margin-top: 70px;
    min-height: calc(100vh - 70px);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--bg-light) 0%, rgba(52, 152, 219, 0.1) 100%);
    padding: var(--spacing-xxl) 0;
    min-height: 80vh;
    display: flex;
    align-items: center;
}

.hero__content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.hero__text {
    max-width: 500px;
}

.hero__subtitle {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--secondary-color);
    margin-bottom: var(--spacing-sm);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.hero__description {
    font-size: 1.1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.hero__image {
    position: relative;
    text-align: center;
}

.hero__image::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    border-radius: 50%;
    opacity: 0.1;
    z-index: -1;
}

.hero__avatar {
    width: 250px;
    height: 250px;
    border-radius: 50%;
    object-fit: cover;
    border: 5px solid var(--bg-white);
    box-shadow: 0 10px 30px var(--shadow-medium);
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 1rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    text-decoration: none;
    transition: var(--transition-fast);
    cursor: pointer;
    border: 2px solid transparent;
}

.btn--primary {
    background-color: var(--secondary-color);
    color: var(--bg-white);
}

.btn--primary:hover {
    background-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px var(--shadow-medium);
}

.btn--outline {
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}

.btn--outline:hover {
    background-color: var(--secondary-color);
    color: var(--bg-white);
}

/* Cards */
.card {
    background-color: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: 0 5px 20px var(--shadow-light);
    overflow: hidden;
    transition: var(--transition-medium);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--shadow-medium);
}

.card__image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

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

.card__title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.card__description {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

.card__meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 0.9rem;
    color: var(--text-light);
}

/* Grid Layouts */
.grid {
    display: grid;
    gap: var(--spacing-lg);
}

.grid--2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid--3 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
    background-color: var(--bg-dark);
    color: var(--bg-white);
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
}

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

.footer__content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer__title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--bg-white);
}

.footer__description {
    color: var(--text-light);
    line-height: 1.6;
}

.footer__links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.footer__subtitle {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--bg-white);
}

.footer__list {
    list-style: none;
}

.footer__list li {
    margin-bottom: var(--spacing-xs);
}

.footer__link,
.footer__text {
    color: var(--text-light);
    transition: var(--transition-fast);
}

.footer__link:hover {
    color: var(--secondary-color);
}

.footer__social {
    display: flex;
    gap: var(--spacing-sm);
}

.footer__social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: var(--text-light);
    transition: var(--transition-fast);
}

.footer__social-link:hover {
    background-color: var(--secondary-color);
    color: var(--bg-white);
    transform: translateY(-2px);
}

.footer__bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer__bottom-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.footer__copyright {
    color: var(--text-light);
    font-size: 0.9rem;
}

.footer__legal-link {
    color: var(--text-light);
    font-size: 0.9rem;
    transition: var(--transition-fast);
}

.footer__legal-link:hover {
    color: var(--secondary-color);
}

/* ==========================================================================
   Responsive Design
   ========================================================================== */
@media (max-width: 768px) {
    :root {
        --container-padding: 1rem;
        --spacing-xxl: 3rem;
    }
    
    .nav__menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background-color: var(--bg-white);
        transition: var(--transition-medium);
        box-shadow: 0 5px 20px var(--shadow-light);
    }
    
    .nav__menu.show {
        left: 0;
    }
    
    .nav__list {
        flex-direction: column;
        padding: var(--spacing-lg);
        gap: var(--spacing-sm);
    }
    
    .nav__link {
        padding: var(--spacing-md);
        font-size: 1.1rem;
    }
    
    .nav__toggle {
        display: block;
    }
    
    .hero__content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-lg);
    }
    
    .hero__text {
        order: 2;
        max-width: none;
    }
    
    .hero__image {
        order: 1;
    }
    
    .hero__avatar {
        width: 200px;
        height: 200px;
    }
    
    .footer__content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .footer__links {
        grid-template-columns: 1fr;
    }
    
    .footer__bottom-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero__avatar {
        width: 150px;
        height: 150px;
    }
    
    .btn {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: 0.9rem;
    }
}