/* ============================================================
   Portfolio — styles.css
   Light Academic Theme
   ============================================================ */

/* --- Custom Properties --- */
:root {
  --color-bg:          #FFFFFF;
  --color-bg-alt:      #F8F9FA;
  --color-text:        #2D3748;
  --color-text-sub:    #64748B;
  --color-accent:      #2563EB;
  --color-accent-hover:#1D4ED8;
  --color-border:      #E2E8F0;
  --color-card-shadow: rgba(0, 0, 0, 0.06);

  --font-family: "Inter", "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  --radius:      10px;
  --transition:  0.25s ease;
  --max-width:   960px;
}

/* --- Reset & Base --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--transition);
}

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

/* --- Focus --- */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 4px;
}

/* --- Skip Link --- */
.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  background: var(--color-accent);
  color: #fff;
  padding: 8px 16px;
  border-radius: var(--radius);
  font-weight: 600;
  z-index: 1000;
  transition: top var(--transition);
}

.skip-link:focus {
  top: 16px;
  color: #fff;
}

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.site-logo:hover {
  color: var(--color-accent);
}

/* --- Desktop Nav --- */
.nav-desktop .nav-list {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-desktop .nav-list a {
  color: var(--color-text-sub);
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: color var(--transition);
}

.nav-desktop .nav-list a:hover,
.nav-desktop .nav-list a[aria-current="true"] {
  color: var(--color-accent);
}

/* --- Mobile Nav (details/summary) --- */
.nav-mobile {
  display: none;
  position: relative;
}

.nav-mobile summary {
  list-style: none;
  cursor: pointer;
  padding: 8px;
  display: flex;
  align-items: center;
}

.nav-mobile summary::-webkit-details-marker {
  display: none;
}

.hamburger-icon {
  display: flex;
  flex-direction: column;
  gap: 5px;
  width: 22px;
}

.hamburger-icon span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

.nav-mobile[open] .hamburger-icon span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-mobile[open] .hamburger-icon span:nth-child(2) {
  opacity: 0;
}

.nav-mobile[open] .hamburger-icon span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.nav-list-mobile {
  list-style: none;
  position: absolute;
  top: calc(100% + 12px);
  right: 0;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 12px 0;
  min-width: 200px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.nav-list-mobile li a {
  display: block;
  padding: 10px 24px;
  color: var(--color-text-sub);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color var(--transition), background var(--transition);
}

.nav-list-mobile li a:hover {
  color: var(--color-accent);
  background: rgba(37, 99, 235, 0.06);
}

/* ============================================================
   Hero
   ============================================================ */
.hero-section {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 140px 24px 100px;
  background: linear-gradient(
    170deg,
    #EEF2FF 0%,
    var(--color-bg) 50%
  );
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-avatar {
  width: 130px;
  height: 130px;
  margin: 0 auto 28px;
  border-radius: 50%;
  overflow: hidden;
  border: 3px solid var(--color-border);
  background: var(--color-bg-alt);
}

.hero-avatar svg,
.hero-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-name {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--color-text);
  margin-bottom: 8px;
}

.hero-title {
  font-size: 1.1rem;
  color: var(--color-text-sub);
  margin-bottom: 8px;
  font-weight: 500;
}

.hero-tagline {
  font-size: 1rem;
  color: var(--color-text-sub);
  max-width: 480px;
  margin: 0 auto 32px;
}

.hero-links {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  color: var(--color-text);
  font-size: 0.85rem;
  font-weight: 500;
  transition: border-color var(--transition), color var(--transition), box-shadow var(--transition);
}

.hero-link-btn:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.12);
}

/* ============================================================
   Sections
   ============================================================ */
.section {
  padding: 96px 0;
}

.section-alt {
  background: var(--color-bg-alt);
}

.section-heading {
  font-size: clamp(1.4rem, 3vw, 1.8rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 48px;
  text-align: center;
  color: var(--color-text);
}

.section-heading::after {
  content: "";
  display: block;
  width: 40px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
  margin: 14px auto 0;
}

/* ============================================================
   About
   ============================================================ */
.about-catch {
  text-align: center;
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: 32px;
  letter-spacing: 0.01em;
}

.about-content {
  max-width: 680px;
  margin: 0 auto 32px;
}

.about-content p {
  color: var(--color-text-sub);
  margin-bottom: 16px;
  text-align: justify;
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.tag {
  display: inline-block;
  padding: 5px 14px;
  background: rgba(37, 99, 235, 0.07);
  color: var(--color-accent);
  border: 1px solid rgba(37, 99, 235, 0.18);
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
}

/* ============================================================
   Works
   ============================================================ */
.works-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
}

.work-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform var(--transition), box-shadow var(--transition);
}

.work-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px var(--color-card-shadow);
}

.work-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--color-text);
  line-height: 1.5;
}

.work-card p {
  color: var(--color-text-sub);
  font-size: 0.9rem;
  margin-bottom: 16px;
  line-height: 1.7;
}

.work-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 16px;
}

.work-tags .tag {
  font-size: 0.72rem;
  padding: 3px 10px;
}

.work-card .card-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-accent);
}

.work-card .card-link::after {
  content: " →";
}

/* ============================================================
   Publications
   ============================================================ */
.publications-intro {
  text-align: center;
  color: var(--color-text-sub);
  margin-bottom: 40px;
  max-width: 500px;
  margin-left: auto;
  margin-right: auto;
}

.pub-links {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
  max-width: 720px;
  margin: 0 auto;
}

.pub-link-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 32px 20px;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  text-align: center;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.pub-link-card:hover {
  border-color: var(--color-accent);
  box-shadow: 0 6px 20px var(--color-card-shadow);
  transform: translateY(-2px);
  color: var(--color-accent);
}

.pub-link-card svg {
  color: var(--color-accent);
}

.pub-link-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.pub-link-status {
  font-size: 0.78rem;
  color: var(--color-text-sub);
  background: var(--color-bg-alt);
  padding: 2px 10px;
  border-radius: 4px;
}

/* ============================================================
   Contact
   ============================================================ */
.contact-text {
  text-align: center;
  color: var(--color-text-sub);
  max-width: 480px;
  margin: 0 auto 32px;
}

.btn {
  display: inline-block;
  padding: 14px 36px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 1rem;
  text-align: center;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
  border: none;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.25);
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  color: #fff;
}

#contact .container {
  text-align: center;
}

/* ============================================================
   Footer
   ============================================================ */
.site-footer {
  padding: 40px 0;
  text-align: center;
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-alt);
}

.footer-links {
  display: flex;
  gap: 20px;
  justify-content: center;
  margin-bottom: 16px;
}

.footer-links a {
  color: var(--color-text-sub);
  transition: color var(--transition), transform var(--transition);
}

.footer-links a:hover {
  color: var(--color-accent);
  transform: translateY(-2px);
}

.footer-copy {
  color: var(--color-text-sub);
  font-size: 0.82rem;
}

/* ============================================================
   Scroll Reveal (JS adds .is-visible)
   ============================================================ */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 767px) {
  .nav-desktop {
    display: none;
  }

  .nav-mobile {
    display: block;
  }

  .hero-section {
    min-height: auto;
    padding: 140px 24px 80px;
  }

  .hero-avatar {
    width: 100px;
    height: 100px;
  }

  .section {
    padding: 64px 0;
  }

  .works-grid {
    grid-template-columns: 1fr;
  }

  .pub-links {
    grid-template-columns: 1fr;
  }

  .hero-links {
    flex-direction: column;
    align-items: center;
  }
}

@media (min-width: 768px) and (max-width: 1023px) {
  .works-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }

  .work-card:hover,
  .pub-link-card:hover {
    transform: none;
    box-shadow: none;
  }

  .btn:hover {
    transform: none;
  }

  .footer-links a:hover {
    transform: none;
  }

  .hero-link-btn:hover {
    box-shadow: none;
  }
}