/* ========================================
   First Down - AI Consulting Company Website
   Modern Gray Theme with Professional Design
   ======================================== */

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

:root {
    /* Color Palette - Modern Gray Theme */
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --accent-color: #3498db;
    --text-dark: #2c3e50;
    --text-medium: #5a6c7d;
    --text-light: #95a5a6;
    --bg-white: #ffffff;
    --bg-light: #f8f9fa;
    --bg-dark: #2c3e50;
    --border-color: #e0e6ed;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
    
    /* Typography */
    --font-main: 'Noto Sans JP', 'Helvetica Neue', Arial, sans-serif;
    --font-heading: 'Noto Sans JP', 'Helvetica Neue', Arial, sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Container */
    --container-max: 1200px;
    --container-padding: 2rem;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-main);
    color: var(--text-dark);
    line-height: 1.8;
    background-color: var(--bg-white);
    overflow-x: hidden;
}

/* ========================================
   2. Typography
   ======================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 2rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-medium);
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: all 0.3s ease;
}

a:hover {
    color: var(--primary-color);
}

/* ========================================
   3. Layout Components
   ======================================== */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

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

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    position: relative;
}

.section-title h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    margin: var(--spacing-sm) auto 0;
}

/* ========================================
   4. Header & Navigation
   ======================================== */
.header {
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem var(--container-padding);
}

.logo {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.logo img {
    height: 50px;
    width: auto;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-menu li a {
    color: var(--text-dark);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.nav-menu li a:hover,
.nav-menu li a.active {
    background: var(--bg-light);
    color: var(--accent-color);
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
    padding: 0.5rem;
}

.menu-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    transition: all 0.3s ease;
}

/* ========================================
   5. Hero Section
   ======================================== */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--bg-white);
    padding: var(--spacing-xl) 0;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><rect fill="rgba(255,255,255,0.02)" width="50" height="50"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
}

.hero h1 {
    color: var(--bg-white);
    font-size: 3.5rem;
    margin-bottom: var(--spacing-md);
    animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: rgba(255, 255, 255, 0.9);
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-description {
    font-size: 1.1rem;
    max-width: 800px;
    margin: 0 auto var(--spacing-md);
    color: rgba(255, 255, 255, 0.85);
    line-height: 1.8;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.btn {
    display: inline-block;
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
    text-decoration: none;
}

.btn-primary {
    background: var(--accent-color);
    color: var(--bg-white);
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-outline {
    background: transparent;
    color: var(--bg-white);
    border: 2px solid var(--bg-white);
}

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

/* ========================================
   6. Content Sections
   ======================================== */
.content-section {
    background: var(--bg-white);
}

.content-section:nth-child(even) {
    background: var(--bg-light);
}

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

.content-card {
    background: var(--bg-white);
    padding: var(--spacing-md);
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
}

.content-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.content-card h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.content-card p {
    color: var(--text-medium);
}

/* ========================================
   7. Icon & Feature Boxes
   ======================================== */
.feature-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--accent-color), #2980b9);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-sm);
    font-size: 1.8rem;
    color: var(--bg-white);
}

/* ========================================
   8. Company Info Section
   ======================================== */
.company-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.info-item {
    padding: var(--spacing-md);
    background: var(--bg-white);
    border-left: 4px solid var(--accent-color);
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
}

.info-item h4 {
    color: var(--primary-color);
    font-size: 1rem;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
}

.info-item p {
    color: var(--text-dark);
    font-size: 1.1rem;
    margin: 0;
}

/* ========================================
   9. Footer
   ======================================== */
.footer {
    background: var(--bg-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-lg) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.footer-section h4 {
    color: var(--bg-white);
    margin-bottom: var(--spacing-sm);
}

.footer-section p,
.footer-section a {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
}

.footer-section a:hover {
    color: var(--bg-white);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-md);
    text-align: center;
    color: rgba(255, 255, 255, 0.6);
}

/* ========================================
   10. Animations
   ======================================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeInUp 0.8s ease-out;
}

/* ========================================
   11. Responsive Design
   ======================================== */
@media (max-width: 768px) {
    :root {
        --spacing-xl: 3rem;
        --container-padding: 1rem;
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.8rem; }
    h3 { font-size: 1.5rem; }
    
    .header-container {
        flex-wrap: wrap;
    }
    
    .menu-toggle {
        display: flex;
    }
    
    .nav-menu {
        flex-direction: column;
        width: 100%;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }
    
    .nav-menu.active {
        max-height: 400px;
        padding: var(--spacing-sm) 0;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .content-grid {
        grid-template-columns: 1fr;
    }
    
    .company-info {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .btn {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }
}