/* Portfolio v4 — hiring-optimized, structured for conversion
   Pair with Tailwind Play CDN in v4/index.html. */

:root {
  color-scheme: light;
  --v4-ink: #141312;
  --v4-ink-soft: #3d3a36;
  --v4-ink-muted: #6b6560;
  --v4-paper: #f4f1eb;
  --v4-paper-warm: #ebe6dc;
  --v4-paper-cool: #fdfcfa;
  --v4-line: #1a1917;
  --v4-line-light: #d4d0c8;
  --v4-accent: #2d4a3e;
  --v4-accent-hover: #1f342c;
  --v4-focus: #1a5fb4;
}

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

body {
  margin: 0;
  min-height: 100dvh;
  color: var(--v4-ink);
  background-color: var(--v4-paper);
  background-image:
    linear-gradient(
      color-mix(in srgb, var(--v4-paper-warm) 50%, transparent) 1px,
      transparent 1px
    ),
    linear-gradient(
      90deg,
      color-mix(in srgb, var(--v4-paper-warm) 50%, transparent) 1px,
      transparent 1px
    );
  background-size: 24px 24px;
}

a:focus-visible {
  outline: 2px solid var(--v4-focus);
  outline-offset: 2px;
}

/* Skip link */

.v4-skip {
  position: absolute;
  left: 1rem;
  top: -100%;
  z-index: 200;
  padding: 0.5rem 1rem;
  background: var(--v4-paper);
  color: var(--v4-ink);
  font-weight: 600;
  border: 2px solid var(--v4-line);
  text-decoration: none;
}

.v4-skip:focus {
  top: 0.5rem;
}

/* Header */

.v4-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 2px solid var(--v4-line);
  background: color-mix(in srgb, var(--v4-paper) 92%, transparent);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.v4-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.v4-nav a {
  display: inline-block;
  padding: 0.35rem 0.65rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--v4-ink-soft);
  text-decoration: none;
  border-radius: 4px;
  transition: background 0.12s, color 0.12s;
}

.v4-nav a:hover {
  background: var(--v4-paper-warm);
  color: var(--v4-ink);
}

/* Hero */

.v4-hero {
  padding: clamp(2.5rem, 6vw, 5rem) 0;
}

.v4-portrait {
  width: clamp(160px, 28vw, 240px);
  aspect-ratio: 1;
  overflow: hidden;
  border: 3px solid var(--v4-line);
  border-radius: 50%;
  background: #fff;
}

.v4-portrait img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 20%;
}

.v4-summary {
  list-style: none;
  margin: 1.25rem 0 0;
  padding: 0.75rem 0 0.75rem 1rem;
  border-left: 3px solid var(--v4-accent);
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--v4-ink-soft);
}

.v4-summary li + li {
  margin-top: 0.15rem;
}

/* Buttons */

.v4-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 1.1rem;
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--v4-ink);
  background: var(--v4-paper-cool);
  border: 2px solid var(--v4-line);
  box-shadow: 2px 2px 0 0 var(--v4-line);
  transition: transform 0.1s, box-shadow 0.1s, background 0.1s;
}

.v4-btn:hover {
  background: var(--v4-paper-warm);
  transform: translate(1px, 1px);
  box-shadow: 1px 1px 0 0 var(--v4-line);
}

.v4-btn--primary {
  background: var(--v4-accent);
  color: var(--v4-paper);
}

.v4-btn--primary:hover {
  background: var(--v4-accent-hover);
  color: var(--v4-paper);
}

/* Sections */

.v4-section {
  padding: clamp(2.5rem, 5vw, 4rem) 0;
}

.v4-section--alt {
  background: var(--v4-paper-cool);
  border-top: 1px solid var(--v4-line-light);
  border-bottom: 1px solid var(--v4-line-light);
}

.v4-section-title {
  font-family: "IBM Plex Serif", Georgia, serif;
  font-size: clamp(1.5rem, 3.5vw, 2rem);
  font-weight: 600;
  line-height: 1.2;
  margin: 0 0 0.5rem;
  color: var(--v4-ink);
}

.v4-section-intro {
  margin: 0 0 2rem;
  font-size: 0.9375rem;
  color: var(--v4-ink-muted);
  max-width: 42rem;
}

/* Tag lists */

.v4-tag-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
}

.v4-tag-list li {
  padding: 0.2rem 0.55rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--v4-ink);
  background: #fff;
  border: 1px solid var(--v4-line);
}

.v4-tag-list--sm li {
  font-size: 0.6875rem;
  padding: 0.15rem 0.45rem;
}

.v4-tag-list--lg li {
  font-size: 0.8125rem;
  padding: 0.3rem 0.7rem;
}

.v4-tag-list--muted li {
  color: var(--v4-ink-soft);
  border-color: var(--v4-line-light);
  background: var(--v4-paper);
}

/* Case studies */

.v4-case {
  border: 2px solid var(--v4-line);
  background: #fff;
  margin-bottom: 1.5rem;
}

.v4-case-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--v4-line-light);
  background: var(--v4-paper);
}

.v4-case-title {
  font-family: "IBM Plex Serif", Georgia, serif;
  font-size: 1.125rem;
  font-weight: 600;
  margin: 0;
  color: var(--v4-ink);
}

.v4-case-meta {
  margin: 0.25rem 0 0;
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.75rem;
  color: var(--v4-ink-muted);
}

.v4-case-body {
  padding: 1.25rem;
}

.v4-case-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .v4-case-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.v4-case-label {
  font-size: 0.6875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--v4-accent);
  margin: 0 0 0.35rem;
}

.v4-case-grid p {
  margin: 0;
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--v4-ink-soft);
}

/* Timeline */

.v4-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.v4-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 4px;
  bottom: 4px;
  width: 2px;
  background: var(--v4-line-light);
}

.v4-timeline-item {
  position: relative;
  padding-left: 2rem;
  padding-bottom: 1.75rem;
}

.v4-timeline-item:last-child {
  padding-bottom: 0;
}

.v4-timeline-marker {
  position: absolute;
  left: 0;
  top: 6px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 2px solid var(--v4-accent);
  background: var(--v4-paper);
}

.v4-timeline-content {
  padding-top: 0;
}

.v4-impact {
  list-style: none;
  margin: 0;
  padding: 0;
}

.v4-impact li {
  position: relative;
  padding-left: 1rem;
  font-size: 0.8125rem;
  line-height: 1.55;
  color: var(--v4-ink-soft);
}

.v4-impact li + li {
  margin-top: 0.3rem;
}

.v4-impact li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--v4-accent);
  font-weight: 600;
}

/* Thinking cards */

.v4-thinking-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .v4-thinking-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.v4-thinking-card {
  padding: 1.25rem;
  border: 2px solid var(--v4-line);
  background: #fff;
}

.v4-thinking-principle {
  margin: 0 0 0.75rem;
  font-family: "IBM Plex Serif", Georgia, serif;
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--v4-ink);
}

.v4-thinking-practice {
  margin: 0;
  padding-left: 0.75rem;
  border-left: 2px solid var(--v4-accent);
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--v4-ink-soft);
}

/* Stack tiers */

.v4-stack-grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .v4-stack-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.v4-stack-tier {
  padding: 1.25rem;
  border: 2px solid var(--v4-line);
  background: #fff;
}

.v4-stack-tier-title {
  margin: 0 0 0.5rem;
  font-size: 0;
}

.v4-stack-tier-badge {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  font-size: 0.6875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  border: 1px solid;
}

.v4-stack-tier-badge--core {
  color: #fff;
  background: var(--v4-accent);
  border-color: var(--v4-accent);
}

.v4-stack-tier-badge--strong {
  color: var(--v4-accent);
  background: transparent;
  border-color: var(--v4-accent);
}

.v4-stack-tier-badge--working {
  color: var(--v4-ink-muted);
  background: transparent;
  border-color: var(--v4-line-light);
}

/* Writing cards */

.v4-writing-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .v4-writing-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.v4-writing-card {
  padding: 1.25rem;
  border: 2px solid var(--v4-line);
  background: #fff;
}

/* Contact */

.v4-contact {
  padding-bottom: clamp(3rem, 6vw, 5rem);
}

.v4-contact-cta {
  margin-bottom: 2rem;
  padding: 1.25rem 1.5rem;
  border-left: 4px solid var(--v4-accent);
  background: var(--v4-paper-cool);
}

.v4-contact-grid {
  display: grid;
  gap: 2rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .v4-contact-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.v4-contact-link {
  color: var(--v4-accent);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.12s;
}

.v4-contact-link:hover {
  border-bottom-color: var(--v4-accent);
}

/* Smooth scroll */

html {
  scroll-behavior: smooth;
  scroll-padding-top: 4rem;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

/* Print-friendly */

@media print {
  .v4-header,
  .v4-skip {
    display: none;
  }

  .v4-section--alt {
    background: #fff;
    border: none;
  }

  body {
    background: #fff;
    background-image: none;
  }

  .v4-btn {
    border: 1px solid #999;
    box-shadow: none;
  }
}