:root {
    --ink: #1a1a1a;
    --paper: #faf9f7;
    --accent: #1b4332;
    --accent-light: #2d6a4f;
    --muted: #5c5c5c;
    --border: #e5e3df;
    --surface: #ffffff;
    --highlight: #f0ede8;
}

* {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

html {
    scroll-behavior: smooth;
}

/* Custom scrollbar */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--paper); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--muted); }

/* Filter buttons */
.filter-btn {
    color: var(--muted);
    background: transparent;
    cursor: pointer;
    transition: all 0.2s ease;
}
.filter-btn.active {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}
.filter-btn:hover:not(.active) {
    background: var(--highlight);
}

/* Research cards */
.research-card {
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.research-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(0,0,0,0.06);
}

/* Category tags */
.tag-crypto {
    background: #e8f0e9;
    color: #1b4332;
}
.tag-token {
    background: #ede7f6;
    color: #4527a0;
}
.tag-industry {
    background: #e3f2fd;
    color: #1565c0;
}
.tag-quant {
    background: #e8f5e9;
    color: #2e5a30;
}
.tag-bilingual {
    background: #fff3e0;
    color: #8a5a1e;
}

/* Project metrics */
.metric-box {
    background: var(--highlight);
    border-radius: 0.5rem;
    padding: 0.5rem 0.5rem;
    text-align: center;
}
.metric-value {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--accent);
}
.metric-label {
    font-size: 0.6rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--muted);
}

/* Fade-in on scroll */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}