:root {
    /* Fresh Cyan & Yellow Palette */
    --primary: #06b6d4;     /* Cyan 500 */
    --primary-light: #67e8f9; /* Cyan 300 */
    --primary-dark: #0891b2;  /* Cyan 600 */
    
    --accent: #facc15;      /* Yellow 400 */
    --accent-light: #fef08a; /* Yellow 200 */
    
    --bg-color: #f0fdfa;    /* Very light cyan/teal background */
    --bg-pattern: #ecfeff;
    
    --text-main: #334155;   /* Slate 700 */
    --text-muted: #64748b;  /* Slate 500 */
    --text-light: #94a3b8;
    
    --card-bg: #ffffff;
    --card-border: #ccfbf1; /* Teal 100 */
    --card-shadow: 0 4px 6px -1px rgba(6, 182, 212, 0.05), 0 2px 4px -1px rgba(6, 182, 212, 0.03);
    --card-hover-shadow: 0 20px 25px -5px rgba(6, 182, 212, 0.1), 0 10px 10px -5px rgba(6, 182, 212, 0.04);
    
    --font-sans: 'Inter', 'Noto Sans JP', sans-serif;
}

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

body {
    font-family: var(--font-sans);
    background-color: #ffffff;
    color: var(--text-main);
    min-height: 100vh;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    position: relative;
}

/* Header */
.site-header {
    padding: 24px 0;
    margin-bottom: 20px;
    position: sticky;
    top: 0;
    z-index: 100;
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;
}

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

.logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
    gap: 12px;
}

.header-logo {
    height: 48px;
    width: auto;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-dark);
    letter-spacing: -0.02em;
}

/* Hero Section */
.hero-section {
    text-align: center;
    padding: 60px 0 80px;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--primary-dark);
    letter-spacing: -0.03em;
}

.hero-content h1 span {
    color: var(--accent);
    position: relative;
    display: inline-block;
}

.hero-content h1 span::after {
    content: '';
    position: absolute;
    bottom: 8px;
    left: 0;
    width: 100%;
    height: 12px;
    background: var(--accent-light);
    z-index: -1;
    transform: rotate(-2deg);
    opacity: 0.6;
}

.hero-text {
    font-size: 1.25rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
    font-weight: 500;
}

/* Tools Grid */
.tools-section {
    padding-bottom: 80px;
    flex: 1;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 32px;
}

.tool-card {
    background: var(--card-bg);
    border: 2px solid transparent;
    border-radius: 32px;
    padding: 40px 32px;
    text-decoration: none;
    color: inherit;
    transition: all 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.tool-card:hover {
    transform: translateY(-8px) scale(1.01);
    box-shadow: var(--card-hover-shadow);
    border-color: var(--primary-light);
}

.tool-icon {
    width: 80px;
    height: 80px;
    background: #ecfeff; /* Cyan 50 */
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    transition: all 0.3s ease;
    color: var(--primary);
    position: relative;
    overflow: hidden;
}

/* Circle decoration behind icon */
.tool-icon::before {
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    background: var(--primary);
    opacity: 0;
    transition: opacity 0.3s ease;
    border-radius: 50%;
    z-index: 0;
}

.tool-card:hover .tool-icon {
    transform: rotate(10deg);
    color: white;
}

.tool-card:hover .tool-icon::before {
    opacity: 1;
}

.tool-icon i {
    font-size: 40px;
    position: relative;
    z-index: 1;
}

.tool-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-main);
    margin-bottom: 12px;
}

.tool-description {
    font-size: 1rem;
    color: var(--text-muted);
    line-height: 1.6;
}


/* Footer */
footer {
    padding: 60px 0 40px;
    text-align: center;
    border-top: 1px solid rgba(6, 182, 212, 0.1);
    margin-top: auto;
}

footer p {
    color: var(--text-light);
    font-size: 0.9rem;
    font-weight: 500;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-content h1 {
        font-size: 2.5rem;
    }
    
    .container {
        padding: 0 20px;
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .site-header {
        padding: 16px 0;
    }
    
    .tool-card {
        padding: 32px 24px;
    }
}