/* ========================================
   CSS Reset & Base Styles
   ======================================== */

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

html {
    font-size: 100%; /* 16px */
}

/* ========================================
   CSS Variables
   ======================================== */

:root {
    /* Colors */
    --color-text: #000000;
    --color-text-light: #4b5563;
    --color-text-lighter: #6b7280;
    --color-background: #ffffff;
    --color-border: #e5e7eb;
    --color-link: #2563eb;
    --color-link-hover: #1d4ed8;

    /* Font */
    --font-serif: 'Iowan Old Style', Georgia, serif;
    --font-display: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;

    /* Font sizes */
    --text-base: 1rem;      /* 16px */
    --text-lg: 1.125rem;    /* 18px */
    --text-xl: 1.25rem;     /* 20px */
    --text-2xl: 1.5rem;     /* 24px */
    --text-3xl: 1.875rem;   /* 30px */
    --text-4xl: 2.5rem;     /* 40px */

    /* Font weights */
    --font-normal: 400;
    --font-semibold: 600;
    --font-bold: 700;

    /* Spacing */
    --spacing-4: 1rem;      /* 16px */
    --spacing-6: 1.5rem;    /* 24px */
    --spacing-8: 2rem;      /* 32px */
    --spacing-10: 2.5rem;   /* 40px */
    --spacing-12: 3rem;     /* 48px */
    --spacing-14: 3.5rem;   /* 56px */
    --spacing-16: 4rem;     /* 64px */
    --spacing-20: 5rem;     /* 80px */

    /* Layout */
    --max-width: 684px;
    --padding-x: 0.75rem;  /* 12px */
}

/* ========================================
   Body & Layout
   ======================================== */

body {
    font-family: var(--font-serif);
    font-size: var(--text-base);
    line-height: 1.75;
    color: var(--color-text);
    background-color: var(--color-background);
    padding: 0;
}

.content-wrapper {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-8) var(--padding-x);
}

.container {
    width: 100%;
}

/* ========================================
   Typography
   ======================================== */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: var(--font-bold);
    line-height: 1.2;
    color: var(--color-text);
}

h1 {
    font-size: var(--text-3xl);
}

h2 {
    font-size: var(--text-2xl);
    margin-bottom: var(--spacing-4);
    text-align: center;
    color: var(--color-text-light);
}

h3 {
    font-size: var(--text-xl);
}

p {
    margin-bottom: var(--spacing-4);
    color: var(--color-text);
}

strong {
    font-weight: var(--font-bold);
}

a {
    color: var(--color-link);
    text-decoration: underline;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--color-link-hover);
}

ul, ol {
    margin-bottom: var(--spacing-6);
    padding-left: var(--spacing-6);
}

li {
    margin-bottom: 0.5rem;
    line-height: 1.75;
}

/* ========================================
   Header
   ======================================== */

/* Mobile Header */
.mobile-header {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--color-background);
    z-index: 100;
    height: 48px;
    padding: 0 var(--padding-x);
}

.mobile-header-content {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.mobile-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: var(--font-bold);
    margin: 0;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: #6b7280;
    opacity: 0;
    transition: opacity 0.3s ease-in-out;
}

.mobile-header.visible .mobile-title {
    opacity: 1;
}

.menu-button {
    background: none;
    border: none;
    padding: 0.5rem;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.menu-icon {
    display: block;
    width: 24px;
    height: 2px;
    background-color: #6b7280;
    transition: all 0.3s ease;
}

.menu-button:hover .menu-icon {
    background-color: #374151;
}

/* Desktop Header */
.desktop-header {
    padding: var(--spacing-10) 0;
    text-align: center;
    display: block;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-4);
}

.logo {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    box-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
}

.site-title {
    font-family: var(--font-display);
    font-size: var(--text-4xl);
    font-weight: var(--font-bold);
    margin: 0;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: #6b7280;
}

.tagline {
    font-size: var(--text-base);
    color: var(--color-text-light);
    margin-top: var(--spacing-4);
}

/* ========================================
   Sections
   ======================================== */

.section {
    padding: var(--spacing-4) 0;
}

.intro-section {
    padding-top: 0;
}

.research-image {
    margin: var(--spacing-8) 0;
}

.research-image img {
    width: 100%;
    height: auto;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.research-image figcaption {
    margin-top: var(--spacing-4);
    font-size: 0.875rem;
    color: var(--color-text-lighter);
    text-align: center;
    font-style: italic;
}

.email-link,
.address-link {
    color: var(--color-link);
    text-decoration: underline;
}

.email-link:hover,
.address-link:hover {
    color: var(--color-link-hover);
}

/* ========================================
   Footer
   ======================================== */

.footer {
    border-top: 1px solid var(--color-border);
    padding-top: var(--spacing-8);
    margin-top: var(--spacing-20);
    text-align: center;
}

.footer-info {
    font-size: 0.875rem;
    color: var(--color-text-lighter);
    margin-bottom: var(--spacing-6);
}

.footer-info p {
    margin-bottom: 0.25rem;
    line-height: 1.6;
}

.footer-copyright {
    font-size: 0.75rem;
    color: var(--color-text-lighter);
    margin-top: var(--spacing-4);
}

/* ========================================
   Responsive Design
   ======================================== */

@media (min-width: 768px) {
    .mobile-header {
        display: none !important;
    }

    .content-wrapper {
        padding: var(--spacing-14) var(--padding-x);
    }

    .section {
        padding: var(--spacing-6) 0;
    }

    .desktop-header {
        padding: var(--spacing-12) 0;
    }
}

@media (max-width: 767px) {
    .mobile-header {
        display: block;
    }

    .logo {
        width: 50px;
        height: 50px;
    }
}