/* Portfolio — Kotaro Takahashi | Verynaze Inc. */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --bg: #0a0e17;
  --bg-card: #111827;
  --bg-card-hover: #1a2332;
  --border: rgba(148,163,184,0.12);
  --border-hover: rgba(99,130,255,0.35);
  --text: #e2e8f0;
  --text-muted: #94a3b8;
  --text-dim: #64748b;
  --accent: #6382ff;
  --accent-soft: rgba(99,130,255,0.12);
  --green: #34d399;
  --green-soft: rgba(52,211,153,0.12);
  --radius: 12px;
  --transition: 0.25s cubic-bezier(0.4,0,0.2,1);
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: #8da6ff; }

img { max-width: 100%; display: block; }

/* --- Layout --- */
.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

section {
  padding: 64px 0;
  border-bottom: 1px solid var(--border);
}

section:last-of-type { border-bottom: none; }

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(10,14,23,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow var(--transition);
}

.nav.scrolled { box-shadow: 0 4px 30px rgba(0,0,0,0.3); }

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav-logo {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: 0.02em;
}

.nav-links { display: flex; gap: 24px; list-style: none; }

.nav-links a {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.03em;
  transition: color var(--transition);
}

.nav-links a:hover { color: var(--text); }

.nav-hamburger {
  display: none;
  background: none; border: none; cursor: pointer;
  width: 28px; height: 20px; position: relative;
}

.nav-hamburger span {
  display: block; width: 100%; height: 2px;
  background: var(--text-muted);
  position: absolute; left: 0;
  transition: all var(--transition);
}

.nav-hamburger span:nth-child(1) { top: 0; }
.nav-hamburger span:nth-child(2) { top: 9px; }
.nav-hamburger span:nth-child(3) { top: 18px; }

/* --- Hero --- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: 60px;
}

.hero-content { max-width: 640px; }

.hero-label {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 16px;
  padding: 4px 14px;
  border: 1px solid rgba(99,130,255,0.3);
  border-radius: 20px;
}

.hero h1 {
  font-size: clamp(32px, 6vw, 56px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}

.hero h1 span { color: var(--accent); }

.hero-desc {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.8;
  max-width: 520px;
  margin-bottom: 32px;
}

.hero-stats {
  display: flex;
  gap: 40px;
  flex-wrap: wrap;
}

.hero-stat-num {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
  line-height: 1;
}

.hero-stat-label {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 4px;
}

/* --- Section Headings --- */
.section-head {
  margin-bottom: 40px;
}

.section-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 8px;
}

.section-title {
  font-size: clamp(24px, 4vw, 36px);
  font-weight: 700;
  letter-spacing: -0.01em;
}

/* --- Project Cards --- */
.projects-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition);
}

.project-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-3px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.25);
}

.project-header {
  padding: 28px 28px 0;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.project-icon {
  width: 48px; height: 48px;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px;
  flex-shrink: 0;
}

.project-badge {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.08em;
  padding: 3px 10px;
  border-radius: 6px;
  text-transform: uppercase;
  white-space: nowrap;
}

.badge-system  { background: var(--accent-soft); color: var(--accent); }
.badge-web     { background: var(--green-soft); color: var(--green); }
.badge-tool    { background: rgba(251,191,36,0.12); color: #fbbf24; }
.badge-ai      { background: rgba(168,85,247,0.12); color: #a855f7; }

.project-body { padding: 20px 28px 28px; }

.project-name {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.project-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 16px;
}

.project-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 16px;
}

.tech-tag {
  font-size: 11px;
  font-weight: 500;
  padding: 3px 10px;
  border-radius: 6px;
  background: rgba(148,163,184,0.08);
  color: var(--text-dim);
  border: 1px solid var(--border);
}

.project-role {
  font-size: 12px;
  color: var(--text-dim);
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.project-role strong { color: var(--text-muted); }

/* Ratio bar */
.ratio-bar {
  display: flex; align-items: center; gap: 10px;
  margin-top: 12px;
}

.ratio-label {
  font-size: 11px;
  color: var(--text-dim);
  white-space: nowrap;
  min-width: 50px;
}

.ratio-track {
  flex: 1;
  height: 4px;
  background: rgba(148,163,184,0.1);
  border-radius: 2px;
  overflow: hidden;
}

.ratio-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.6s ease;
}

/* --- Skills --- */
.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.skill-group {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.skill-group-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}

.skill-items {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.skill-item {
  font-size: 13px;
  padding: 5px 14px;
  border-radius: 8px;
  background: rgba(148,163,184,0.06);
  color: var(--text-muted);
  border: 1px solid var(--border);
}

/* --- About --- */
.about-content {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}

.about-text p {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.9;
  margin-bottom: 16px;
}

.about-details {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.about-detail-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 4px;
}

.about-detail-value {
  font-size: 14px;
  color: var(--text);
}

/* --- Contact --- */
.contact-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.contact-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all var(--transition);
}

.contact-link:hover {
  border-color: var(--border-hover);
  background: var(--bg-card-hover);
}

.contact-link-icon {
  width: 36px; height: 36px;
  border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 16px;
  background: var(--accent-soft);
  flex-shrink: 0;
}

.contact-link-name {
  font-size: 14px;
  font-weight: 500;
  color: var(--text);
}

.contact-link-url {
  font-size: 12px;
  color: var(--text-dim);
}

/* --- Footer --- */
.footer {
  padding: 32px 0;
  text-align: center;
  font-size: 12px;
  color: var(--text-dim);
}

/* --- Tablet (768px+) --- */
@media (min-width: 768px) {
  .container { padding: 0 40px; }

  .projects-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .skills-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .about-details {
    grid-template-columns: repeat(4, 1fr);
  }

  .contact-links {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .contact-link { flex: 1; min-width: 200px; }
}

/* --- Desktop (1024px+) --- */
@media (min-width: 1024px) {
  section { padding: 80px 0; }

  .hero { min-height: 90vh; }

  .hero-stats { gap: 56px; }

  .about-content {
    grid-template-columns: 2fr 1fr;
  }
}

/* --- Mobile (< 768px) --- */
@media (max-width: 767px) {
  .nav-hamburger { display: block; }

  .nav-links {
    display: none;
    position: absolute;
    top: 60px; left: 0; right: 0;
    flex-direction: column;
    background: rgba(10,14,23,0.97);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 16px 20px;
    gap: 4px;
    border-bottom: 1px solid var(--border);
  }

  .nav-links.open { display: flex; }

  .nav-links a {
    display: block;
    padding: 10px 0;
    font-size: 15px;
  }

  .hero-stats { gap: 28px; }

  .hero-stat-num { font-size: 24px; }

  .project-header { padding: 20px 20px 0; }
  .project-body { padding: 16px 20px 20px; }
}

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

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}