.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.75rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 600;
  line-height: 1;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  transition: background-color var(--duration-fast), color var(--duration-fast), border-color var(--duration-fast), transform var(--duration-fast);
  white-space: nowrap;
  min-height: 2.75rem;
}

.btn:active {
  transform: scale(0.98);
}

.btn--primary {
  background-color: var(--color-accent);
  color: var(--color-accent-text);
  box-shadow: var(--shadow-sm);
}

.btn--primary:hover {
  background-color: var(--color-accent-hover);
  box-shadow: var(--shadow-accent);
  transform: translateY(-1px);
}

.btn--secondary {
  background-color: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border);
}

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

.btn--ghost {
  color: var(--color-text-muted);
  padding-inline: var(--space-3);
}

.btn--ghost:hover {
  color: var(--color-text);
  background-color: var(--color-surface);
}

.btn--sm {
  padding: 0.5rem 0.875rem;
  font-size: 0.8125rem;
  min-height: 2.25rem;
}

.btn--lg {
  padding: 1rem 1.75rem;
  font-size: 1rem;
  min-height: 3.25rem;
}

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  transition: background-color var(--duration-fast), color var(--duration-fast);
}

.theme-toggle:hover {
  background-color: var(--color-surface);
  color: var(--color-text);
}

.theme-toggle__icon {
  width: 1.125rem;
  height: 1.125rem;
}

.theme-toggle__icon--light {
  display: block;
}

.theme-toggle__icon--dark {
  display: none;
}

[data-theme="dark"] .theme-toggle__icon--dark {
  display: block;
}

[data-theme="dark"] .theme-toggle__icon--light {
  display: none;
}

.tag {
  display: inline-block;
  padding: 0.25rem 0.625rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
}

.tag--accent {
  color: var(--color-accent);
  background-color: var(--color-accent-muted);
  border-color: transparent;
}

.card {
  display: flex;
  flex-direction: column;
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  overflow: hidden;
  position: relative;
  transition: border-color var(--duration-normal), transform var(--duration-normal) var(--ease-out), box-shadow var(--duration-normal);
}

.card::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background-color: var(--color-accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform var(--duration-normal) var(--ease-out);
  z-index: 2;
}

.card:hover {
  border-color: var(--color-accent);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card:hover::before {
  transform: scaleY(1);
}

.card__visual {
  aspect-ratio: 16 / 10;
  background-color: var(--color-surface);
  position: relative;
  overflow: hidden;
}

.card__visual-inner {
  position: absolute;
  inset: 0;
}

.card__image,
.case-study-hero__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;
  display: block;
}

.card__body {
  padding: var(--space-5);
  display: flex;
  flex-direction: column;
  flex: 1;
  gap: var(--space-3);
}

.card__meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.card__year {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-subtle);
}

.card__title {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--color-text);
  transition: color var(--duration-fast);
}

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

.card__desc {
  font-size: 0.875rem;
  line-height: 1.6;
  flex: 1;
}

.card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: auto;
  padding-top: var(--space-2);
}

.card__link-overlay {
  position: absolute;
  inset: 0;
  z-index: 1;
}

.card__link-overlay:focus-visible {
  outline-offset: -3px;
}

.card--lab {
  border-style: dashed;
}

.card--lab:hover {
  transform: none;
  box-shadow: none;
}

.card--lab .card__visual {
  aspect-ratio: 4 / 3;
}

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-8);
}

.filter-btn {
  padding: 0.5rem 1rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-muted);
  background-color: transparent;
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  transition: color var(--duration-fast), background-color var(--duration-fast), border-color var(--duration-fast);
  min-height: 2.5rem;
}

.filter-btn:hover {
  color: var(--color-text);
  border-color: var(--color-border);
}

.filter-btn.is-active {
  color: var(--color-accent-text);
  background-color: var(--color-accent);
  border-color: var(--color-accent);
}

.filter-btn:focus-visible {
  outline-offset: 2px;
}

.hero {
  max-width: 48rem;
}

.hero__label {
  margin-bottom: var(--space-5);
}

.hero__title {
  margin-bottom: var(--space-5);
}

.hero__title em {
  font-style: normal;
  color: var(--color-accent);
}

.hero__statement {
  font-size: clamp(1.125rem, 2.5vw, 1.375rem);
  line-height: 1.65;
  color: var(--color-text-muted);
  max-width: 42ch;
  margin-bottom: var(--space-8);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.hero__status {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-top: var(--space-8);
  font-size: 0.8125rem;
  color: var(--color-text-subtle);
}

.hero__status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-success);
  flex-shrink: 0;
}

.stat-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
  padding: var(--space-6);
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.stat__value {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--color-text);
}

.stat__label {
  font-size: 0.8125rem;
  color: var(--color-text-subtle);
}

.skill-group {
  margin-bottom: var(--space-6);
}

.skill-group__title {
  font-size: 0.75rem;
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-subtle);
  margin-bottom: var(--space-3);
}

.skill-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.timeline {
  position: relative;
  padding-left: var(--space-6);
}

.timeline::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.5rem;
  bottom: 0.5rem;
  width: 1px;
  background-color: var(--color-border);
}

.timeline__item {
  position: relative;
  padding-bottom: var(--space-8);
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__item::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--space-6) - 3px);
  top: 0.5rem;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--color-accent);
  border: 2px solid var(--color-bg);
}

.timeline__period {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-subtle);
  margin-bottom: var(--space-2);
}

.timeline__role {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: var(--space-1);
}

.timeline__company {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-3);
}

.timeline__desc {
  font-size: 0.875rem;
}

.form {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text);
}

.form-label__required {
  color: var(--color-accent);
  margin-left: 0.125rem;
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  transition: border-color var(--duration-fast), box-shadow var(--duration-fast);
}

.form-input:hover,
.form-textarea:hover {
  border-color: var(--color-text-subtle);
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-muted);
  outline: none;
}

.form-input.is-invalid,
.form-textarea.is-invalid {
  border-color: var(--color-error);
}

.form-input.is-invalid:focus,
.form-textarea.is-invalid:focus {
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.15);
}

.form-textarea {
  min-height: 9rem;
  resize: vertical;
}

.form-error {
  font-size: 0.8125rem;
  color: var(--color-error);
  min-height: 1.25rem;
}

.form-hint {
  font-size: 0.8125rem;
  color: var(--color-text-subtle);
}

.form-status {
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  display: none;
}

.form-status.is-visible {
  display: block;
}

.form-status--success {
  background-color: rgba(34, 197, 94, 0.1);
  color: var(--color-success);
  border: 1px solid rgba(34, 197, 94, 0.25);
}

.form-status--error {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--color-error);
  border: 1px solid rgba(239, 68, 68, 0.25);
}

.social-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.social-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.625rem 1rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  transition: color var(--duration-fast), border-color var(--duration-fast), background-color var(--duration-fast);
}

.social-link:hover {
  color: var(--color-text);
  border-color: var(--color-border);
  background-color: var(--color-surface-hover);
}

.article-card {
  display: grid;
  gap: var(--space-3);
  padding: var(--space-5);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  transition: border-color var(--duration-fast), background-color var(--duration-fast);
}

.article-card:hover {
  border-color: var(--color-border);
  background-color: var(--color-bg-elevated);
}

.article-card__date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--color-text-subtle);
}

.article-card__title {
  font-size: 1.125rem;
  font-weight: 600;
  transition: color var(--duration-fast);
}

.article-card:hover .article-card__title {
  color: var(--color-accent);
}

.article-card__excerpt {
  font-size: 0.875rem;
}

.article-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.8125rem;
  color: var(--color-text-subtle);
}

.prose {
  max-width: var(--container-narrow);
  font-size: 1.0625rem;
  line-height: 1.75;
}

.prose > * + * {
  margin-top: var(--space-5);
}

.prose h2 {
  margin-top: var(--space-10);
  margin-bottom: var(--space-4);
  font-size: 1.5rem;
}

.prose h3 {
  margin-top: var(--space-8);
  margin-bottom: var(--space-3);
}

.prose p {
  color: var(--color-text-muted);
}

.prose a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose a:hover {
  color: var(--color-accent-hover);
}

.prose ul,
.prose ol {
  padding-left: var(--space-5);
  color: var(--color-text-muted);
}

.prose ul {
  list-style: disc;
}

.prose ol {
  list-style: decimal;
}

.prose li + li {
  margin-top: var(--space-2);
}

.prose blockquote {
  padding-left: var(--space-5);
  border-left: 3px solid var(--color-accent);
  font-style: italic;
  color: var(--color-text-muted);
}

.prose code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  padding: 0.15em 0.4em;
  background-color: var(--color-surface);
  border-radius: var(--radius-sm);
}

.prose pre {
  padding: var(--space-5);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  overflow-x: auto;
}

.prose pre code {
  padding: 0;
  background: none;
  font-size: 0.8125rem;
  line-height: 1.6;
}

.case-study-hero {
  aspect-ratio: 21 / 9;
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: var(--space-10);
  border: 1px solid var(--color-border-subtle);
}

.case-study-meta {
  display: grid;
  gap: var(--space-5);
  padding: var(--space-6);
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-10);
}

.case-study-meta__item dt {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-subtle);
  margin-bottom: var(--space-1);
}

.case-study-meta__item dd {
  font-size: 0.9375rem;
  color: var(--color-text);
}

.back-to-top {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  z-index: 50;
  width: 2.75rem;
  height: 2.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  opacity: 0;
  visibility: hidden;
  transform: translateY(0.5rem);
  transition: opacity var(--duration-normal), visibility var(--duration-normal), transform var(--duration-normal), background-color var(--duration-fast), color var(--duration-fast);
  box-shadow: var(--shadow-md);
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--color-accent);
  color: var(--color-accent-text);
  border-color: var(--color-accent);
}

.cta-block {
  padding: var(--space-10);
  background-color: var(--color-bg-elevated);
  border: 2px solid var(--color-accent);
  border-radius: var(--radius-xl);
  text-align: center;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

.cta-block::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background-color: var(--color-accent);
}

.cta-block__title {
  margin-bottom: var(--space-4);
}

.cta-block__desc {
  margin-inline: auto;
  margin-bottom: var(--space-6);
}

.error-page {
  min-height: calc(100vh - var(--header-height) - 12rem);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding-block: var(--space-16);
}

.error-page__code {
  font-family: var(--font-display);
  font-size: clamp(4rem, 15vw, 8rem);
  font-weight: 700;
  letter-spacing: -0.05em;
  color: var(--color-surface);
  line-height: 1;
  margin-bottom: var(--space-4);
}

.error-page__title {
  margin-bottom: var(--space-4);
}

.error-page__desc {
  margin-inline: auto;
  margin-bottom: var(--space-8);
}

.availability-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  font-size: 0.875rem;
  background-color: var(--color-accent-muted);
  border: 1px solid rgba(79, 140, 255, 0.2);
  border-radius: var(--radius-md);
  color: var(--color-text);
  margin-bottom: var(--space-6);
}

@media (min-width: 768px) {
  .stat-row {
    grid-template-columns: repeat(4, 1fr);
  }

  .case-study-meta {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* --- Dev portfolio enhancements --- */

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.375rem 0.875rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-accent);
  background-color: var(--color-accent-muted);
  border: 1px solid var(--color-accent);
  border-radius: 999px;
  margin-bottom: var(--space-5);
}

.hero-badge__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background-color: var(--color-success);
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

@media (prefers-reduced-motion: reduce) {
  .hero-badge__dot {
    animation: none;
  }
}

.hero__title-highlight {
  display: inline;
  background-color: var(--color-accent-muted);
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
  padding: 0 0.15em;
}

.terminal {
  background-color: var(--color-terminal-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  line-height: 1.7;
}

.terminal__bar {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background-color: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.terminal__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: #475569;
}

.terminal__dot--red { background-color: #ef4444; }
.terminal__dot--yellow { background-color: #eab308; }
.terminal__dot--green { background-color: #22c55e; }

.terminal__title {
  margin-left: auto;
  font-size: 0.6875rem;
  color: #64748b;
  letter-spacing: 0.04em;
}

.terminal__body {
  padding: var(--space-5);
  color: var(--color-terminal-text);
  min-height: 14rem;
}

.terminal__line {
  display: block;
  white-space: pre-wrap;
  word-break: break-word;
}

.terminal__prompt {
  color: var(--color-code-string);
  user-select: none;
}

.terminal__kw { color: var(--color-code-keyword); }
.terminal__fn { color: var(--color-code-fn); }
.terminal__str { color: var(--color-code-string); }
.terminal__cm { color: var(--color-code-comment); }

.terminal__cursor {
  display: inline-block;
  width: 0.55em;
  height: 1.1em;
  background-color: var(--color-accent);
  vertical-align: text-bottom;
  margin-left: 2px;
  animation: blink-cursor 1s step-end infinite;
}

@keyframes blink-cursor {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .terminal__cursor {
    animation: none;
  }
}

.tech-marquee {
  overflow: hidden;
  border-block: 1px solid var(--color-border-subtle);
  background-color: var(--color-bg-elevated);
  padding-block: var(--space-4);
  margin-bottom: var(--space-2);
}

.tech-marquee__track {
  display: flex;
  width: max-content;
  animation: marquee-scroll 35s linear infinite;
}

.tech-marquee__track:hover {
  animation-play-state: paused;
}

.tech-marquee__item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding-inline: var(--space-6);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.tech-marquee__item::before {
  content: "//";
  color: var(--color-accent);
  font-weight: 700;
}

@keyframes marquee-scroll {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

@media (prefers-reduced-motion: reduce) {
  .tech-marquee__track {
    animation: none;
    flex-wrap: wrap;
    width: 100%;
    justify-content: center;
    gap: var(--space-3);
  }
}

.process-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-10);
}

.process-step {
  padding: var(--space-5);
  background-color: var(--color-bg-elevated);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  transition: border-color var(--duration-fast), box-shadow var(--duration-fast);
}

.process-step:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-sm);
}

.process-step__num {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
}

.process-step__title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.process-step__desc {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  line-height: 1.55;
}

.stat-row {
  border: 1px solid var(--color-border-subtle);
  box-shadow: var(--shadow-md);
}

.stat__value {
  color: var(--color-accent);
}

@media (min-width: 768px) {
  .process-row {
    grid-template-columns: repeat(4, 1fr);
  }
}