/* ==========================================================================
   WiscAI Shared Styles
   Shared across: index.html, about.html, privacy.html, cohort.html
   ========================================================================== */

/* A. CSS Custom Properties */
:root {
    --color-bg-primary: #0a1628;
    --color-bg-secondary: #0f2137;
    --color-bg-card: #152642;
    --color-accent: #4a9eff;
    --color-accent-warm: #ff6b4a;
    --color-text-primary: #ffffff;
    --color-text-secondary: #cbd5e1;
    --color-text-muted: #94a3b8;
    --color-border: rgba(148, 163, 184, 0.15);
    --font-display: 'Playfair Display', Georgia, serif;
    --font-body: 'Source Sans 3', -apple-system, sans-serif;
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* B. Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}

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

/* C. Navigation */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 1.25rem 3rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(10, 22, 40, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    transition: var(--transition-smooth);
}

/* D. Logo */
.logo {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--color-text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.logo span {
    color: var(--color-accent);
}

/* E. Nav Links */
.nav-links {
    display: flex;
    gap: 2.5rem;
    list-style: none;
}

.nav-links a {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-size: 0.925rem;
    font-weight: 400;
    transition: var(--transition-smooth);
}

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

/* F. Nav CTA */
.nav-cta {
    padding: 0.75rem 1.5rem;
    background: transparent;
    border: 1px solid var(--color-border);
    color: var(--color-text-primary);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: var(--transition-smooth);
}

.nav-cta:hover {
    background: var(--color-text-primary);
    color: var(--color-bg-primary);
    border-color: var(--color-text-primary);
}

/* G. Footer */
footer {
    padding: 3rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    text-align: center;
    border-top: 1px solid var(--color-border);
}

.footer-copy {
    color: var(--color-text-muted);
    font-size: 0.875rem;
}

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

.footer-links a {
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.875rem;
    transition: var(--transition-smooth);
}

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

/* H. Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--color-text-primary);
    cursor: pointer;
    padding: 0.5rem;
}

/* I. Shared Mobile Breakpoint */
@media (max-width: 768px) {
    nav {
        padding: 1rem 1.5rem;
    }

    .mobile-menu-toggle {
        display: block;
    }

    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        background: rgba(10, 22, 40, 0.98);
        backdrop-filter: blur(20px);
        padding: 1rem 1.5rem;
        gap: 0;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links li {
        padding: 0.75rem 0;
        border-bottom: 1px solid var(--color-border);
    }

    .nav-links li:last-child {
        border-bottom: none;
    }

    footer {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}