@media (min-width: 768px) {
  .column { max-width: 820px; }
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  background: var(--accent);
  color: var(--surface);
  border-radius: 10px;
  font-family: 'Inter', sans-serif;
  font-weight: 500;
  font-size: 13px;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: opacity 0.15s ease;
}

.btn-primary:hover { opacity: 0.88; }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  background: transparent;
  color: var(--ink);
  border-radius: 10px;
  font-family: 'Inter', sans-serif;
  font-weight: 500;
  font-size: 13px;
  border: 1px solid var(--line);
  cursor: pointer;
  text-decoration: none;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.btn-secondary:hover {
  border-color: var(--muted);
  background: var(--accent-soft);
}

.rp-hero {
  margin-bottom: 32px;
}

.rp-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.rp-year {
  font-size: 12px;
  color: var(--muted);
  letter-spacing: 0.03em;
}

.rp-title {
  font-family: 'Inter', sans-serif;
  font-size: 28px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.02em;
  margin-bottom: 8px;
  line-height: 1.2;
}

.rp-tagline {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.6;
  margin-bottom: 20px;
}

.rp-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}


.rp-section {
  margin-bottom: 36px;
}

.rp-img-placeholder {
  aspect-ratio: 16 / 9;
  background: var(--accent-soft);
  border: 1px solid var(--line);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: var(--muted);
}

.rp-img-placeholder svg {
  width: 40px;
  height: 40px;
  opacity: 0.4;
}

.rp-img-placeholder span {
  font-size: 12px;
  letter-spacing: 0.03em;
}

.rp-section-title {
  font-family: 'Inter', sans-serif;
  font-size: 11px;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 12px;
}

.rp-body {
  font-size: 14px;
  color: var(--ink);
  line-height: 1.75;
  opacity: 0.85;
  text-align: justify;
}

.rp-list {
  list-style: none;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.rp-list li {
  font-size: 13px;
  color: var(--ink);
  opacity: 0.8;
  line-height: 1.55;
  padding-left: 16px;
  position: relative;
  text-align: justify;
}

.rp-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  opacity: 0.6;
}

.rp-stack {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--line);
  border-radius: 10px;
  overflow: hidden;
}

.rp-stack-item {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
}

.rp-stack-item:last-child {
  border-bottom: none;
}

.rp-stack-name {
  font-size: 12px;
  font-weight: 600;
  color: var(--ink);
  min-width: 140px;
  flex-shrink: 0;
}

.rp-stack-role {
  font-size: 12px;
  color: var(--muted);
  line-height: 1.5;
}

/* reuse badge from portfolio.css */
.research-status-badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 20px;
  border: 1px solid transparent;
}

.research-status-badge.experimental {
  color: #b45309;
  background: #fef3c7;
  border-color: #fcd34d;
}

.research-status-badge.prototype {
  color: #1d4ed8;
  background: #dbeafe;
  border-color: #93c5fd;
}

.research-status-badge.published {
  color: #15803d;
  background: #dcfce7;
  border-color: #86efac;
}

.research-status-badge.open-source {
  color: #7c3aed;
  background: #ede9fe;
  border-color: #c4b5fd;
}

[data-theme="dark"] .research-status-badge.experimental {
  color: #fcd34d;
  background: rgba(180,83,9,0.2);
  border-color: rgba(252,211,77,0.3);
}

[data-theme="dark"] .research-status-badge.prototype {
  color: #93c5fd;
  background: rgba(29,78,216,0.2);
  border-color: rgba(147,197,253,0.3);
}

[data-theme="dark"] .research-status-badge.published {
  color: #86efac;
  background: rgba(21,128,61,0.2);
  border-color: rgba(134,239,172,0.3);
}

[data-theme="dark"] .research-status-badge.open-source {
  color: #c4b5fd;
  background: rgba(124,58,237,0.2);
  border-color: rgba(196,181,253,0.3);
}

@media (max-width: 480px) {
  .rp-title { font-size: 22px; }
  .rp-stack-name { min-width: 100px; }
}