/* 
 * ANTHROPIC/CLAUDE-INSPIRED DESIGN SYSTEM
 * Clean, sophisticated, human-centric.
 * Based on anthropic.com and claude.com design patterns
 */

:root {
    /* Main Palette - Warm, sophisticated neutrals (from Anthropic) */
    --bg-dark: #191919;
    --bg-light: #faf9f7;
    --bg-white: #ffffff;
    --gray-mid: #e5e4e0;
    --gray-border: #d4d3cf;
    --gray-text: #6e6d6a;

    /* Accents */
    --accent-primary: #61a5c2;
    /* Pacific Blue */
    --accent-blue: #8da4b8;
    --accent-green: #9cac88;

    /* Text Colors */
    --text-primary: #191919;
    --text-secondary: #5e5d5a;
    --text-muted: #8a8985;
    --text-inverse: #faf9f7;

    /* Typography - Using Google Fonts that mimic Styrene/Tiempos */
    --font-heading: 'Poppins', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'Lora', Georgia, serif;

    /* Spacing & Layout */
    --container-width: 1400px;
    --container-narrow: 1000px;
    --spacing-unit: 8px;
    --border-radius: 12px;
    --border-radius-sm: 8px;

    /* Animation - Smooth, subtle (Anthropic style) */
    --transition-fast: 0.15s ease-out;
    --transition-smooth: 0.3s ease-out;
}

/* RESET & BASE */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    background-color: var(--bg-light);
    color: var(--text-primary);
    font-family: var(--font-body);
    line-height: 1.7;
    font-size: 1.125rem;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

/* TYPOGRAPHY */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-heading);
    color: var(--text-primary);
    font-weight: 500;
    letter-spacing: -0.025em;
    line-height: 1.15;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    margin-bottom: 1.5rem;
    font-weight: 500;
    line-height: 1.1;
}

h2 {
    font-size: clamp(1.75rem, 3vw, 2.5rem);
    margin-bottom: 1.5rem;
}

h3 {
    font-size: 1.35rem;
    margin-bottom: 0.75rem;
    font-weight: 500;
}

p {
    margin-bottom: 1.5rem;
    color: var(--text-secondary);
}

a {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition-fast);
}

/* UTILITIES */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 2rem;
    width: 100%;
}

.container-narrow {
    max-width: var(--container-narrow);
}

.section {
    padding: 5rem 0;
}

/* NAVIGATION - Anthropic style (minimal, clean) */
.navbar {
    padding: 1.5rem 0;
    position: sticky;
    top: 0;
    background-color: rgba(250, 249, 247, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: 100;
    border-bottom: 1px solid transparent;
    transition: all var(--transition-fast);
}

.navbar.scrolled {
    border-bottom: 1px solid var(--gray-mid);
    padding: 1rem 0;
}

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

.logo {
    font-family: var(--font-heading);
    font-weight: 600;
    font-size: 1.25rem;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-img {
    height: 48px;
    width: auto;
    border-radius: 4px;
    transition: transform var(--transition-smooth), filter var(--transition-smooth);
}

.logo:hover .logo-img {
    transform: rotate(-5deg) scale(1.08);
    filter: drop-shadow(0 2px 8px rgba(97, 165, 194, 0.3));
}

/* Background Watermark Logo */
.watermark-logo {
    position: fixed;
    bottom: -80px;
    right: -80px;
    width: 400px;
    height: 400px;
    opacity: 0.04;
    pointer-events: none;
    z-index: 0;
    animation: float 20s ease-in-out infinite;
    transition: transform 0.1s ease-out;
}

.watermark-logo img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

@keyframes float {

    0%,
    100% {
        transform: translate(0, 0) rotate(0deg);
    }

    25% {
        transform: translate(-15px, -20px) rotate(2deg);
    }

    50% {
        transform: translate(10px, -10px) rotate(-1deg);
    }

    75% {
        transform: translate(-5px, 5px) rotate(1deg);
    }
}

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

.nav-link {
    font-family: var(--font-heading);
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.5rem 0;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-primary);
    transition: width var(--transition-fast);
}

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

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* HERO - Claude.com inspired (bold, impactful) */
.hero {
    padding: 6rem 0 5rem;
    max-width: 100%;
}

.hero-tag {
    display: inline-block;
    font-family: var(--font-heading);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--accent-primary);
    margin-bottom: 1.25rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.hero h1 {
    margin-bottom: 2rem;
}

.hero-lead {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 720px;
    margin-bottom: 2.5rem;
    line-height: 1.7;
}

/* BUTTONS - Anthropic style */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    background-color: var(--bg-dark);
    color: var(--text-inverse);
    font-family: var(--font-heading);
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--bg-dark);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn:hover {
    background-color: #2a2a2a;
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: transparent;
    color: var(--text-primary);
    border: 1px solid var(--gray-border);
}

.btn-secondary:hover {
    border-color: var(--text-primary);
    background-color: transparent;
}

/* Arrow Link - Claude style */
.link-arrow {
    font-family: var(--font-heading);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    transition: gap var(--transition-fast);
}

.link-arrow:hover {
    gap: 0.6rem;
    color: var(--accent-primary);
}

.link-arrow::after {
    content: '→';
    transition: transform var(--transition-fast);
}

/* GRID & CARDS - Minimal Anthropic style */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.card {
    background: var(--bg-white);
    border: 1px solid var(--gray-mid);
    border-radius: var(--border-radius);
    padding: 2rem;
    transition: all var(--transition-smooth);
    display: flex;
    flex-direction: column;
    height: 100%;
    cursor: pointer;
}

.card:hover {
    border-color: var(--gray-border);
    box-shadow: 0 8px 30px -12px rgba(0, 0, 0, 0.08);
}

.card-meta {
    font-family: var(--font-heading);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.card-title {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    transition: color var(--transition-fast);
}

.card:hover .card-title {
    color: var(--accent-primary);
}

.card-desc {
    font-size: 0.95rem;
    color: var(--text-secondary);
    flex-grow: 1;
    line-height: 1.6;
    margin-bottom: 0;
}

/* Tags - Subtle, pill-shaped */
.tags {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-top: 1.25rem;
}

.tag {
    font-family: var(--font-heading);
    font-size: 0.7rem;
    padding: 0.3rem 0.75rem;
    border-radius: 100px;
    background-color: var(--gray-mid);
    color: var(--text-secondary);
    font-weight: 500;
    letter-spacing: 0.02em;
}

/* YEAR SECTIONS - Timeline-based organization */
.year-section {
    margin-bottom: 4rem;
}

.year-header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.year-label {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--accent-primary);
    letter-spacing: -0.02em;
    line-height: 1;
}

.year-line {
    flex: 1;
    height: 1px;
    background: linear-gradient(to right, var(--gray-mid), transparent);
}

.year-section .grid {
    margin-bottom: 0;
}

.year-section .article-list {
    border-top: none;
}

/* SECTION HEADERS - Anthropic research style */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--gray-mid);
}

.section-header h2 {
    margin-bottom: 0;
}

/* RESEARCH/ARTICLE LIST - Anthropic style */
.article-list {
    border-top: 1px solid var(--gray-mid);
}

.article-item {
    display: block;
    padding: 2rem 0;
    border-bottom: 1px solid var(--gray-mid);
    transition: background-color var(--transition-fast);
}

.article-item:hover {
    background-color: rgba(0, 0, 0, 0.01);
}

.article-item:hover h3 {
    color: var(--accent-primary);
}

.article-meta {
    font-family: var(--font-heading);
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
    display: flex;
    gap: 1rem;
    align-items: center;
}

.article-category {
    color: var(--accent-primary);
    font-weight: 500;
}

.article-item h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    transition: color var(--transition-fast);
}

.article-item p {
    font-size: 1rem;
    margin-bottom: 0;
    color: var(--text-secondary);
}

/* ABOUT/CONTENT BOXES */
.content-box {
    background: var(--bg-white);
    padding: 2.5rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--gray-mid);
}

.content-box h3 {
    margin-bottom: 1.5rem;
}

.focus-list {
    list-style: none;
}

.focus-list li {
    padding: 1rem 0;
    border-bottom: 1px solid var(--gray-mid);
}

.focus-list li:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.focus-list strong {
    font-family: var(--font-heading);
    font-weight: 500;
    display: block;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.focus-list span {
    font-size: 0.95rem;
    color: var(--text-secondary);
}

/* CONTACT SECTION */
.contact-section h2 {
    margin-bottom: 0.75rem;
}

.social-links-grid {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.social-link-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background-color: var(--bg-light);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
    border: 1px solid transparent;
}

.social-link-item:hover {
    background-color: var(--bg-white);
    border-color: var(--accent-primary);
    transform: translateX(4px);
}

.social-link-item i {
    font-size: 1.5rem;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
    width: 28px;
    text-align: center;
}

.social-link-item:hover i {
    color: var(--accent-primary);
}

.social-link-item span {
    font-family: var(--font-heading);
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-primary);
}

/* Contact Form */
.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-family: var(--font-heading);
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.875rem 1rem;
    font-family: var(--font-body);
    font-size: 1rem;
    color: var(--text-primary);
    background-color: var(--bg-light);
    border: 1px solid var(--gray-mid);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
    resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
    background-color: var(--bg-white);
    box-shadow: 0 0 0 3px rgba(97, 165, 194, 0.15);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.contact-form .btn {
    align-self: flex-start;
    margin-top: 0.5rem;
}

.contact-form .btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

/* Form Success/Error States */
.form-message {
    padding: 1rem;
    border-radius: var(--border-radius-sm);
    font-family: var(--font-heading);
    font-size: 0.9rem;
    margin-top: 1rem;
}

.form-message.success {
    background-color: rgba(156, 172, 136, 0.15);
    color: #5a6b4a;
    border: 1px solid rgba(156, 172, 136, 0.3);
}

.form-message.error {
    background-color: rgba(194, 97, 97, 0.15);
    color: #8b4a4a;
    border: 1px solid rgba(194, 97, 97, 0.3);
}

/* FOOTER - Clean, minimal */
footer {
    border-top: 1px solid var(--gray-mid);
    padding: 3rem 0;
    margin-top: 5rem;
}

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

.footer-brand p {
    margin-bottom: 0.25rem;
}

.footer-brand p:first-child {
    font-family: var(--font-heading);
    font-weight: 600;
    color: var(--text-primary);
}

.footer-brand p:last-child {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    font-size: 1.35rem;
    color: var(--text-muted);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.footer-links a:hover {
    color: var(--accent-primary);
    transform: translateY(-2px);
}

/* TWO COLUMN LAYOUT */
.two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: start;
}

/* MOBILE RESPONSIVE */
@media (max-width: 768px) {
    .navbar {
        padding: 1rem 0;
    }

    .nav-links {
        display: none;
    }

    .hero {
        padding: 4rem 0 3rem;
    }

    .grid {
        grid-template-columns: 1fr;
    }

    .two-col {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .footer-content {
        flex-direction: column;
        gap: 1.5rem;
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }

    .section-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1.25rem;
    }

    .card {
        padding: 1.5rem;
    }

    .content-box {
        padding: 1.5rem;
    }
}