:root {
    --primary-gradient: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
    --secondary-gradient: linear-gradient(135deg, #10b981 0%, #059669 100%);
    --accent-color: #0ea5e9;
    --text-main: #1f2937;
    --text-light: #6b7280;
    --bg-light: #f3f4f6;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --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);
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    --container-width: 1200px;
}

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

body {
    font-family: 'Poppins', system-ui, -apple-system, sans-serif;
    color: var(--text-main);
    background-color: var(--bg-light);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-main);
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

ul {
    list-style: none;
}

/* Layout */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1.5rem;
    width: 100%;
}

main {
    flex: 1;
    padding-bottom: 3rem;
}

/* Header & Nav */
header {
    background: var(--white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    color: var(--text-main);
}

.nav-links a:hover, .nav-links a.active {
    color: #4f46e5;
}

.hamburger {
    display: none;
    cursor: pointer;
    font-size: 1.5rem;
}

/* Hero Section */
.hero {
    background: var(--primary-gradient);
    color: var(--white);
    padding: 4rem 0 6rem;
    text-align: center;
    border-radius: 0 0 2rem 2rem; /* Slight curve at bottom */
    margin-bottom: 3rem;
}

.hero h1 {
    color: var(--white);
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.1rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 2.5rem;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: 50px;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--white);
    color: #4f46e5;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: var(--white);
    backdrop-filter: blur(5px);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Tool Cards / Sections */
.section {
    padding: 3rem 0;
}

.card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    margin-bottom: 2rem;
}

.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-top: -4rem; /* Overlap hero */
}

.tool-card {
    background: var(--white);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    text-align: center;
    transition: transform 0.3s ease;
}

.tool-card:hover {
    transform: translateY(-5px);
}

.tool-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    display: block;
}

/* Forms & Calculators */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.form-control {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #d1d5db;
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: #4f46e5;
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.calc-result {
    margin-top: 2rem;
    padding: 1.5rem;
    background: #e0e7ff;
    border-radius: var(--radius-md);
    text-align: center;
    display: none; /* Hidden by default */
}

.calc-result.show {
    display: block;
    animation: fadeIn 0.5s;
}

.result-value {
    font-size: 2rem;
    font-weight: 700;
    color: #4f46e5;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    background: var(--white);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

th, td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid #e5e7eb;
}

th {
    background: #f9fafb;
    font-weight: 600;
}

/* Accordion */
.accordion-item {
    border: 1px solid #e5e7eb;
    border-radius: var(--radius-md);
    margin-bottom: 1rem;
    background: var(--white);
    overflow: hidden;
}

.accordion-header {
    padding: 1rem 1.5rem;
    background: var(--white);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 500;
}

.accordion-header:hover {
    background: #f9fafb;
}

.accordion-content {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.accordion-item.active .accordion-content {
    padding: 1rem 1.5rem;
    max-height: 500px; /* Arbitrary large height */
}

/* Footer */
footer {
    background: #1f2937;
    color: var(--white);
    padding: 3rem 0;
    margin-top: auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-col h3 {
    color: var(--white);
    margin-bottom: 1.5rem;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: #d1d5db;
}

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

.copyright {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #374151;
    color: #9ca3af;
}

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

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 80px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 2rem;
        box-shadow: var(--shadow-md);
        transform: translateY(-150%);
        transition: transform 0.3s ease;
        z-index: 999;
    }

    .nav-links.active {
        transform: translateY(0);
    }

    .hamburger {
        display: block;
    }

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

    .tool-grid {
        margin-top: 2rem;
    }
}