/* Reset & Base */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
    background-color: var(--color-bg);
    color: var(--color-text);
    font-family: var(--font-body);
    font-size: var(--text-base);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.1;
    margin-top: 0;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}
h1 { font-size: var(--text-4xl); letter-spacing: -0.02em; }
h2 { font-size: var(--text-3xl); letter-spacing: -0.01em; }
h3 { font-size: var(--text-2xl); }
p { margin-top: 0; margin-bottom: var(--spacing-md); }
a { color: var(--color-accent); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--color-accent-hover); text-decoration: underline; }
strong { font-weight: 700; }

/* Layout */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.grid {
    display: grid;
    gap: var(--grid-gap);
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
}

/* Header */
.site-header {
    background-color: var(--color-bg);
    border-bottom: 2px solid var(--color-black);
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4rem;
}
.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: var(--text-lg);
    color: var(--color-black);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.logo:hover { text-decoration: none; color: var(--color-accent); }
.main-nav { display: flex; gap: 1.5rem; }
.main-nav a {
    color: var(--color-text);
    font-weight: 600;
    font-size: var(--text-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.main-nav a:hover, .main-nav a.active {
    color: var(--color-accent);
    text-decoration: underline;
    text-underline-offset: 4px;
}

@media (max-width: 768px) {
    .main-nav { display: none; /* In a real app, implement a mobile menu toggle here */ }
}

/* Footer */
.site-footer {
    background-color: var(--color-black);
    color: var(--color-white);
    padding: var(--spacing-xl) 0 var(--spacing-md);
    margin-top: var(--spacing-xl);
}
.footer-inner {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}
@media (max-width: 768px) {
    .footer-inner { grid-template-columns: 1fr; gap: var(--spacing-md); }
}
.footer-col { display: flex; flex-direction: column; gap: 0.5rem; }
.footer-col strong {
    font-family: var(--font-display);
    font-size: var(--text-lg);
    margin-bottom: var(--spacing-sm);
    color: var(--color-bg);
}
.footer-col a { color: #A0A0A0; font-size: var(--text-sm); }
.footer-col a:hover { color: var(--color-white); }
.footer-bottom {
    border-top: 1px solid #333;
    padding-top: var(--spacing-md);
    font-size: var(--text-xs);
    color: #666;
    text-align: center;
}

/* UI Elements */
.btn {
    display: inline-block;
    background-color: var(--color-accent);
    color: var(--color-white);
    padding: 0.75rem 1.5rem;
    font-weight: 700;
    font-family: var(--font-body);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border: 2px solid var(--color-black);
    box-shadow: var(--shadow-sm);
    transition: transform 0.1s ease, box-shadow 0.1s ease;
    cursor: pointer;
}
.btn:hover {
    color: var(--color-white);
    text-decoration: none;
    transform: translate(-2px, -2px);
    box-shadow: var(--shadow-md);
}
.btn:active {
    transform: translate(0, 0);
    box-shadow: none;
}
.btn-outline {
    background-color: transparent;
    color: var(--color-black);
}
.btn-outline:hover {
    background-color: var(--color-black);
    color: var(--color-white);
}

.tag {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    background-color: var(--color-black);
    color: var(--color-white);
    font-size: var(--text-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-xs);
}

/* Structural Components */
.section-pad { padding: var(--spacing-xl) 0; }
.section-pad-sm { padding: var(--spacing-lg) 0; }

.bg-alt { background-color: var(--color-bg-alt); }
.bg-dark { background-color: var(--color-black); color: var(--color-white); }
.bg-dark h2, .bg-dark h3 { color: var(--color-white); }
.bg-dark a:not(.btn) { color: #A0A0A0; text-decoration: underline; }

.card {
    background-color: var(--color-white);
    border: 2px solid var(--color-black);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
}

/* Utility */
.text-center { text-align: center; }
.mb-0 { margin-bottom: 0; }
.mt-0 { margin-top: 0; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }

/* Forms */
.form-group { margin-bottom: var(--spacing-md); }
.form-label {
    display: block;
    font-weight: 700;
    margin-bottom: 0.5rem;
    font-size: var(--text-sm);
}
.form-input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--color-black);
    background-color: var(--color-white);
    font-family: var(--font-body);
    font-size: var(--text-base);
}
.form-input:focus {
    outline: none;
    border-color: var(--color-accent);
}

/* Tool specific */
.tool-result {
    background-color: var(--color-bg-alt);
    border: 2px dashed var(--color-black);
    padding: var(--spacing-md);
    margin-top: var(--spacing-lg);
    font-size: var(--text-lg);
    font-weight: 700;
    text-align: center;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: var(--spacing-md);
}
th, td {
    border: 1px solid var(--color-border);
    padding: 0.75rem;
    text-align: left;
}
th {
    background-color: var(--color-bg-alt);
    font-weight: 700;
}

/* FAQ */
.faq-item {
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) 0;
}
.faq-item h3 {
    margin-bottom: 0.5rem;
    font-size: var(--text-lg);
}