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

:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #8b5cf6;
    --accent: #ec4899;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --bg: #f9fafb;
    --bg-light: #f3f4f6;
    --border: #e5e7eb;
    --success: #10b981;
    --error: #ef4444;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    color: var(--text-dark);
    background: var(--bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    line-height: 1.6;
}

/* Header & Navigation */
.site-header {
    background: white;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.site-shell-header {
    width: min(1200px, 95vw);
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 2rem;
}

.header-left {
    display: flex;
    align-items: center;
}

.brand {
    color: var(--primary-dark);
    font-weight: 700;
    text-decoration: none;
    font-size: 1.25rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    transition: color 0.3s ease;
}

.brand:hover {
    color: var(--primary-light);
}

.brand i {
    font-size: 1.5rem;
}

/* Navigation Menu */
.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
    flex: 1;
}

.nav-link {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

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

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-dark);
    padding: 0.5rem;
}

.menu-toggle:hover {
    color: var(--primary);
}

/* Main Content */
.site-shell {
    width: min(1200px, 95vw);
    margin: 0 auto;
    flex: 1;
    padding: 2rem 1.5rem;
}

/* Footer */
.site-footer {
    background: white;
    border-top: 1px solid var(--border);
    margin-top: auto;
    padding: 2rem 0;
    color: var(--text-light);
    font-size: 0.9rem;
    text-align: center;
}

/* Hero Section */
.home-hero {
    margin-bottom: 3rem;
}

.home-hero h1 {
    font-size: clamp(1.8rem, 5vw, 2.5rem);
    color: var(--text-dark);
    margin-bottom: 0.75rem;
    font-weight: 700;
}

.home-hero p {
    color: var(--text-light);
    font-size: 1.1rem;
    max-width: 600px;
}

/* Tool Grid */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

/* Tool Card */
.tool-card {
    background: white;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2rem 1.5rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-sm);
}

.tool-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.tool-category {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background: rgba(99, 102, 241, 0.1);
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    width: fit-content;
}

.tool-card h2 {
    font-size: 1.25rem;
    color: var(--text-dark);
    margin-bottom: 0.75rem;
    font-weight: 600;
}

.tool-card p {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.tool-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    background: var(--primary);
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    border: 2px solid var(--primary);
    width: fit-content;
}

.tool-link:hover {
    background: var(--primary-dark);
    border-color: var(--primary-dark);
    transform: translateX(4px);
}

.tool-link i {
    font-size: 1rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }

    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        gap: 0;
        padding: 1rem 0;
        border-bottom: 1px solid var(--border);
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }

    .nav-menu.active {
        max-height: 300px;
        box-shadow: var(--shadow-md);
    }

    .nav-link {
        padding: 0.75rem 1.5rem;
        display: block;
    }

    .nav-link.active::after {
        display: none;
    }

    .nav-link.active {
        background: rgba(99, 102, 241, 0.1);
    }

    .site-shell-header {
        padding: 1rem;
        gap: 1rem;
    }

    .brand {
        font-size: 1.1rem;
        gap: 0.5rem;
    }

    .brand i {
        font-size: 1.3rem;
    }

    .site-shell {
        padding: 1.5rem 1rem;
    }

    .home-hero {
        margin-bottom: 2rem;
    }

    .home-hero h1 {
        font-size: 1.8rem;
    }

    .tool-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .tool-card {
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    .site-shell-header {
        padding: 0.75rem;
    }

    .brand {
        font-size: 1rem;
    }

    .brand i {
        font-size: 1.2rem;
    }

    .home-hero h1 {
        font-size: 1.5rem;
    }

    .home-hero p {
        font-size: 1rem;
    }

    .tool-card {
        padding: 1rem;
    }

    .tool-card h2 {
        font-size: 1.1rem;
    }

    .site-shell {
        padding: 1rem;
    }
}