/* --- Global Variables & Initial Setup --- */
:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --text-color: #2d3748;
    --light-text-color: #718096;
    --bg-color: #f7fafc;
    --card-bg-color: #ffffff;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* --- Header & Navigation --- */
header {
    background-color: var(--card-bg-color);
    box-shadow: var(--shadow-sm);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

#navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}
.logo:hover {
    color: var(--secondary-color);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s ease;
}

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

/* --- Hero Section --- */
.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    text-align: center;
    padding: 5rem 1rem;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 2rem auto;
    font-weight: 300;
}

.btn {
    display: inline-block;
    padding: 12px 28px;
    background-color: var(--card-bg-color);
    color: var(--primary-color);
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* --- Popular Tools Section --- */
.section-title {
    text-align: center;
    font-size: 2.2rem;
    margin: 3rem 0 2rem 0;
    color: var(--text-color);
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.tool-card {
    background-color: var(--card-bg-color);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--border-color);
}

.tool-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.tool-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.tool-card h3 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--text-color);
}

.tool-card p {
    color: var(--light-text-color);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.tool-card .btn {
    padding: 10px 20px;
    font-size: 0.9rem;
}

/* --- Categories Section --- */
.categories {
    background-color: var(--card-bg-color);
    padding: 3rem 0;
    margin-top: 3rem;
    border-radius: 12px;
}
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}
.category-item {
    background-color: var(--bg-color);
    padding: 1.5rem;
    border-radius: 8px;
    text-align: center;
    transition: background-color 0.3s ease;
    cursor: pointer;
}
.category-item:hover {
    background-color: #e2e8f0;
}
.category-item h4 {
    color: var(--primary-color);
}

/* --- Features Section --- */
.features {
    padding: 3rem 0;
    text-align: center;
}
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}
.feature-item h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}
.feature-item p {
    color: var(--light-text-color);
}


/* --- Footer --- */
footer {
    background-color: var(--text-color);
    color: #a0aec0;
    text-align: center;
    padding: 2rem 0;
    margin-top: 3rem;
}

footer p {
    margin: 0.5rem 0;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
}
footer a:hover {
    text-decoration: underline;
}

/* --- Responsive Design --- */
@media (max-width: 768px) {
    .nav-links {
        gap: 1rem;
        font-size: 0.9rem;
    }
    .hero h1 {
        font-size: 2.2rem;
    }
    .hero p {
        font-size: 1rem;
    }
    .section-title {
        font-size: 1.8rem;
    }
    .tools-grid {
        grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    }
}

@media (max-width: 480px) {
    nav {
        flex-direction: column;
        gap: 1rem;
    }
    .hero {
        padding: 3rem 1rem;
    }
    .tools-grid {
        grid-template-columns: 1fr;
    }
}