* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --background-color: #f8fafc;
    --text-color: #1e293b;
    --card-background: #ffffff;
}

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

header {
    background-color: var(--card-background);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

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

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

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

main {
    margin-top: 4rem;
    min-height: calc(100vh - 8rem);
}

.hero {
    text-align: center;
    padding: 4rem 1rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.tools-grid {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 1rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.tool-card {
    background-color: var(--card-background);
    border-radius: 8px;
    padding: 1.5rem;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    cursor: pointer;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.tool-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.tool-card h3 {
    margin-bottom: 0.5rem;
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1001;
}

.modal-content {
    background-color: var(--card-background);
    margin: 5% auto;
    padding: 2rem;
    width: 90%;
    max-width: 800px;
    border-radius: 8px;
    position: relative;
}

.close-btn {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
}

footer {
    background-color: var(--card-background);
    text-align: center;
    padding: 1rem;
    margin-top: 2rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        gap: 1rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .tools-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

/* Tool-specific styles */
.calculator-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    padding: 1rem;
}

.calculator-button {
    padding: 1rem;
    border: none;
    background-color: #e2e8f0;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1.1rem;
}

.calculator-display {
    grid-column: 1 / -1;
    background-color: #f8fafc;
    padding: 1rem;
    text-align: right;
    font-size: 1.5rem;
    margin-bottom: 1rem;
    border-radius: 4px;
}

.unit-converter select,
.unit-converter input {
    width: 100%;
    padding: 0.5rem;
    margin: 0.5rem 0;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
}

.text-tools textarea {
    width: 100%;
    min-height: 200px;
    padding: 0.5rem;
    margin: 0.5rem 0;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
}

.color-picker input[type="color"] {
    width: 100%;
    height: 50px;
    margin: 1rem 0;
}