/* ==========================================================================
   Papyrus Labs - Institutional Design System
   Library of Alexandria meets Bodleian meets Bell Labs
   ========================================================================== */

/* ==========================================================================
   1. Design Tokens
   ========================================================================== */

:root {
    /* Neutrals - Academic Authority */
    --papyrus-charcoal: #1A1A1A;
    --papyrus-slate-900: #0F172A;
    --papyrus-slate-700: #334155;
    --papyrus-slate-500: #64748B;
    --papyrus-slate-300: #CBD5E1;
    --papyrus-slate-100: #F1F5F9;

    /* Papyrus Tones - Warmth and History */
    --papyrus-sand: #E6D5B8;
    --papyrus-ivory: #FAF7F0;
    --papyrus-aged: #D4C4A0;
    --papyrus-brown: #8B7355;
    --papyrus-white: #FFFFFF;

    /* Gold - Academic Excellence (use sparingly) */
    --papyrus-gold-500: #D4AF37;
    --papyrus-gold-600: #B8941F;
    --papyrus-gold-700: #9A7816;

    /* Lapis Lazuli - Primary Accent */
    --lapis-400: #4A7BA7;
    --lapis-500: #2C5F8D;
    --lapis-600: #1E4A6B;

    /* Research Area Colors */
    --research-code: #2C5F8D;
    --research-emotion: #6B5B95;
    --research-practical: #8B7355;
    --research-future: #475569;

    /* Typography */
    --font-display: 'Cormorant Garamond', Georgia, serif;
    --font-body: 'IBM Plex Sans', system-ui, -apple-system, sans-serif;
    --font-mono: 'IBM Plex Mono', 'Courier New', monospace;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    --space-24: 6rem;

    /* Golden ratio spacing */
    --space-golden-xs: 1.618rem;
    --space-golden-sm: 2.618rem;
    --space-golden-md: 4.236rem;
    --space-golden-lg: 6.854rem;

    /* Layout */
    --content-max-narrow: 65ch;
    --content-max-standard: 80ch;
    --content-max-wide: 1200px;

    /* Easing */
    --ease-out: cubic-bezier(0, 0, 0.2, 1);
}

/* ==========================================================================
   2. Reset & Base
   ========================================================================== */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.8;
    color: var(--papyrus-slate-900);
    background: var(--papyrus-ivory);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

/* ==========================================================================
   3. Layout
   ========================================================================== */

.papyrus-container {
    max-width: 1400px;
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--space-6);
    padding-right: var(--space-6);
}

@media (min-width: 768px) {
    .papyrus-container {
        padding-left: var(--space-12);
        padding-right: var(--space-12);
    }
}

@media (min-width: 1024px) {
    .papyrus-container {
        padding-left: var(--space-20);
        padding-right: var(--space-20);
    }
}

/* ==========================================================================
   4. Skip Link
   ========================================================================== */

.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--papyrus-charcoal);
    color: var(--papyrus-white);
    padding: var(--space-2) var(--space-4);
    text-decoration: none;
    z-index: 1000;
}

.skip-link:focus {
    top: 0;
}

/* ==========================================================================
   5. Logo / Wordmark
   ========================================================================== */

.papyrus-logo {
    text-align: center;
}

.logo-text {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    color: var(--papyrus-charcoal);
    margin: 0;
}

.logo-rule {
    width: 200px;
    height: 2px;
    background: linear-gradient(
        90deg,
        transparent 0%,
        var(--lapis-500) 50%,
        transparent 100%
    );
    margin: var(--space-4) auto 0;
    animation: rule-draw 600ms var(--ease-out) forwards;
}

/* Small logo variant */
.papyrus-logo.small .logo-text {
    font-size: 1.25rem;
    letter-spacing: 0.05em;
}

.papyrus-logo.small .logo-rule {
    width: 100px;
    height: 1px;
    margin-top: var(--space-2);
}

/* ==========================================================================
   6. Header
   ========================================================================== */

.papyrus-header {
    background: rgba(255, 255, 255, 0.95);
    border-bottom: 1px solid var(--papyrus-slate-300);
    padding: var(--space-6) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(8px);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header-logo {
    text-decoration: none;
}

.header-nav {
    display: flex;
    gap: var(--space-8);
    align-items: center;
}

.nav-link {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--papyrus-slate-700);
    text-decoration: none;
    transition: color 200ms ease;
    position: relative;
}

.nav-link:hover {
    color: var(--lapis-600);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--lapis-500);
    transform: scaleX(0);
    transition: transform 200ms ease;
}

.nav-link:hover::after {
    transform: scaleX(1);
}

@media (max-width: 768px) {
    .header-nav {
        gap: var(--space-4);
    }

    .nav-link {
        font-size: 0.75rem;
    }
}

/* ==========================================================================
   7. Hero Section
   ========================================================================== */

.hero-section {
    min-height: 80vh;
    display: flex;
    align-items: center;
    background: var(--papyrus-ivory);
    padding-top: var(--space-golden-lg);
    padding-bottom: var(--space-golden-lg);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
    animation: fade-in 800ms var(--ease-out) forwards;
}

.hero-subtitle {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 400;
    line-height: 1.6;
    color: var(--papyrus-slate-700);
    margin: var(--space-8) 0;
    font-style: italic;
}

.hero-description {
    max-width: var(--content-max-narrow);
    margin: var(--space-12) auto 0;
}

.hero-description p {
    font-family: var(--font-body);
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--papyrus-slate-700);
}

@media (max-width: 768px) {
    .hero-section {
        min-height: auto;
        padding-top: var(--space-golden-sm);
        padding-bottom: var(--space-golden-sm);
    }

    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-description p {
        font-size: 1rem;
    }
}

/* ==========================================================================
   8. Section Header
   ========================================================================== */

.section-header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.section-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 500;
    color: var(--papyrus-charcoal);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    margin: 0;
}

.section-rule {
    width: 120px;
    height: 2px;
    background: var(--lapis-500);
    margin: var(--space-4) auto;
}

.section-subtitle {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--papyrus-slate-500);
    max-width: 60ch;
    margin: var(--space-6) auto 0;
}

@media (max-width: 768px) {
    .section-title {
        font-size: 1.5rem;
    }
}

/* ==========================================================================
   9. Research Section & Cards
   ========================================================================== */

.research-section {
    padding-top: var(--space-golden-lg);
    padding-bottom: var(--space-golden-lg);
    background: var(--papyrus-white);
}

.research-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-8);
    max-width: var(--content-max-wide);
    margin: 0 auto;
}

@media (min-width: 768px) {
    .research-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .research-grid {
        gap: var(--space-12);
    }
}

/* Research Cards */
.research-card {
    background: var(--papyrus-white);
    border: 1px solid var(--papyrus-slate-300);
    border-radius: 8px;
    padding: var(--space-8);
    transition: all 300ms ease;
    position: relative;
    overflow: hidden;
}

.research-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    border-color: var(--lapis-500);
}

.research-card__accent {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--accent-color);
}

/* Card color variants */
.research-card--code {
    --accent-color: var(--research-code);
}

.research-card--emotion {
    --accent-color: var(--research-emotion);
}

.research-card--practical {
    --accent-color: var(--research-practical);
}

.research-card__header {
    margin-bottom: var(--space-6);
}

.research-card__category {
    font-family: var(--font-body);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--accent-color);
}

.research-card__title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--papyrus-charcoal);
    margin: 0 0 var(--space-3) 0;
}

.research-card__tagline {
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-style: italic;
    color: var(--papyrus-slate-500);
    margin: 0 0 var(--space-4) 0;
}

.research-card__description {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--papyrus-slate-700);
    margin: 0;
}

.research-card__status {
    display: inline-block;
    margin-top: var(--space-4);
    padding: var(--space-1) var(--space-3);
    background: var(--papyrus-sand);
    border: 1px solid var(--papyrus-aged);
    border-radius: 4px;
    font-family: var(--font-body);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--papyrus-brown);
}

.research-card__link {
    display: inline-block;
    margin-top: var(--space-6);
    font-family: var(--font-body);
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--accent-color);
    text-decoration: none;
    transition: color 200ms ease;
}

.research-card__link:hover {
    color: var(--lapis-600);
}

/* ==========================================================================
   10. Philosophy Section
   ========================================================================== */

.philosophy-section {
    background: var(--papyrus-sand);
    padding-top: var(--space-golden-lg);
    padding-bottom: var(--space-golden-lg);
}

.philosophy-content {
    max-width: 70ch;
    margin: 0 auto;
    text-align: center;
}

.philosophy-paragraph {
    font-family: var(--font-body);
    font-size: 1.125rem;
    line-height: 1.9;
    color: var(--papyrus-brown);
    margin: 0 0 var(--space-8) 0;
}

.philosophy-paragraph--lead {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--papyrus-charcoal);
}

.philosophy-paragraph:last-child {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .philosophy-section {
        padding-top: var(--space-golden-sm);
        padding-bottom: var(--space-golden-sm);
    }

    .philosophy-paragraph {
        font-size: 1rem;
        text-align: left;
    }

    .philosophy-paragraph--lead {
        font-size: 1.125rem;
    }
}

/* ==========================================================================
   11. Footer
   ========================================================================== */

.papyrus-footer {
    background: var(--papyrus-ivory);
    padding: var(--space-golden-md) 0 var(--space-12) 0;
    border-top: 1px solid var(--papyrus-aged);
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

.footer-description {
    font-family: var(--font-body);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--papyrus-slate-700);
    margin: var(--space-8) 0;
}

.footer-meta {
    margin: var(--space-6) 0;
}

.footer-location,
.footer-affiliation {
    font-family: var(--font-body);
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--papyrus-slate-500);
    margin: var(--space-2) 0;
}

.footer-affiliation {
    font-style: italic;
}

.footer-rule {
    width: 200px;
    height: 1px;
    background: linear-gradient(
        90deg,
        transparent 0%,
        var(--lapis-600) 50%,
        transparent 100%
    );
    margin: var(--space-8) auto;
}

.footer-copyright {
    font-family: var(--font-body);
    font-size: 0.75rem;
    color: var(--papyrus-slate-500);
    margin: 0;
}

@media (max-width: 768px) {
    .papyrus-footer {
        padding-top: var(--space-golden-sm);
    }
}

/* ==========================================================================
   12. Animations
   ========================================================================== */

@keyframes fade-in {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes rule-draw {
    from {
        transform: scaleX(0);
    }
    to {
        transform: scaleX(1);
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ==========================================================================
   13. Focus States
   ========================================================================== */

*:focus-visible {
    outline: 2px solid var(--lapis-500);
    outline-offset: 4px;
}