/* ============================================================
   Yusuke Aoki - Academic Personal Website
   ============================================================ */

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

:root {
  --color-bg: #ffffff;
  --color-text: #333333;
  --color-text-light: #666666;
  --color-heading: #1a1a2e;
  --color-accent: #16697a;
  --color-accent-hover: #0d4f5e;
  --color-header-bg: #1a1a2e;
  --color-header-text: #ffffff;
  --color-border: #e0e0e0;
  --color-section-bg: #f8f9fa;
  --color-card-bg: #ffffff;
  --font-sans: 'Source Sans 3', 'Source Sans Pro', sans-serif;
  --font-serif: 'Lora', Georgia, serif;
  --max-width: 960px;
  --header-height: 60px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

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

/* --- Header / Navigation --- */
.site-header {
  background-color: var(--color-header-bg);
  color: var(--color-header-text);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

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

.site-title {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-header-text);
  white-space: nowrap;
}

.site-title a {
  color: var(--color-header-text);
  text-decoration: none;
}

.site-title a:hover {
  color: #ccc;
  text-decoration: none;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 8px;
}

.nav-links a {
  color: var(--color-header-text);
  padding: 8px 14px;
  border-radius: 4px;
  font-size: 0.95rem;
  font-weight: 500;
  transition: background-color 0.2s ease, color 0.2s ease;
  text-decoration: none;
}

.nav-links a:hover {
  background-color: rgba(255, 255, 255, 0.1);
  text-decoration: none;
}

.nav-links a.active {
  background-color: var(--color-accent);
  color: #fff;
}

/* Hamburger menu */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-header-text);
  margin: 5px 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

/* --- Main Content --- */
.main-content {
  flex: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px;
  width: 100%;
}

/* --- Home Page: Profile Section --- */
.profile-section {
  display: flex;
  gap: 48px;
  align-items: flex-start;
}

.profile-photo-wrapper {
  flex-shrink: 0;
}

.profile-photo {
  width: 200px;
  height: 200px;
  border-radius: 12px;
  object-fit: cover;
  border: 3px solid var(--color-border);
  background-color: var(--color-section-bg);
}

.profile-info {
  flex: 1;
}

.profile-info h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  color: var(--color-heading);
  margin-bottom: 12px;
}

.social-icons {
  display: flex;
  gap: 12px;
  margin-bottom: 20px;
}

.social-icons a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background-color: var(--color-heading);
  color: #fff;
  transition: background-color 0.2s ease;
  text-decoration: none;
}

.social-icons a:hover {
  background-color: var(--color-accent);
  text-decoration: none;
}

.social-icons svg {
  width: 18px;
  height: 18px;
  fill: currentColor;
}

.profile-info p {
  margin-bottom: 14px;
  color: var(--color-text);
}

.contact-info {
  margin-top: 16px;
  font-size: 0.95rem;
  color: var(--color-text-light);
}

.contact-info p {
  color: var(--color-text-light);
}

/* --- Page Headers --- */
.page-header {
  margin-bottom: 36px;
}

.page-header h1 {
  font-family: var(--font-serif);
  font-size: 2rem;
  color: var(--color-heading);
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-accent);
}

/* --- Section Headings --- */
.section-heading {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  color: var(--color-heading);
  margin-top: 40px;
  margin-bottom: 20px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--color-border);
}

.subsection-heading {
  font-family: var(--font-sans);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-heading);
  margin-top: 28px;
  margin-bottom: 16px;
}

/* --- Research Items --- */
.research-item {
  margin-bottom: 24px;
  padding-left: 16px;
  border-left: 3px solid var(--color-accent);
}

.research-item .paper-title {
  font-weight: 600;
  color: var(--color-heading);
  margin-bottom: 4px;
}

.research-item .paper-title a {
  color: var(--color-accent);
  font-weight: 600;
}

.research-item .authors {
  font-size: 0.95rem;
  color: var(--color-text-light);
  margin-bottom: 2px;
}

.research-item .venue {
  font-size: 0.9rem;
  color: var(--color-text-light);
  font-style: italic;
}

/* --- Presentation Items --- */
.presentation-item {
  margin-bottom: 28px;
}

.presentation-item .paper-title {
  font-weight: 600;
  color: var(--color-heading);
  margin-bottom: 8px;
}

.presentation-item .paper-title a {
  color: var(--color-accent);
  font-weight: 600;
}

.presentation-list {
  list-style: none;
  padding-left: 0;
}

.presentation-list li {
  position: relative;
  padding-left: 20px;
  margin-bottom: 6px;
  font-size: 0.95rem;
  color: var(--color-text);
}

.presentation-list li::before {
  content: "\2022";
  position: absolute;
  left: 4px;
  color: var(--color-accent);
  font-weight: bold;
}

.presentation-category {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-light);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-top: 8px;
  margin-bottom: 4px;
}

/* --- Media Page --- */
.media-outlets {
  font-size: 1rem;
  line-height: 1.8;
  color: var(--color-text);
  margin-bottom: 24px;
}

.media-outlets .italic {
  font-style: italic;
}

.contributions-list {
  list-style: none;
  padding: 0;
}

.contributions-list li {
  padding: 16px 0;
  border-bottom: 1px solid var(--color-border);
}

.contributions-list li:last-child {
  border-bottom: none;
}

.contributions-list .contrib-title {
  font-weight: 600;
  color: var(--color-heading);
  display: block;
  margin-bottom: 4px;
}

.contributions-list .contrib-title a {
  color: var(--color-accent);
}

.contributions-list .contrib-meta {
  font-size: 0.9rem;
  color: var(--color-text-light);
}

/* --- Footer --- */
.site-footer {
  background-color: var(--color-header-bg);
  color: rgba(255, 255, 255, 0.7);
  text-align: center;
  padding: 20px 24px;
  font-size: 0.85rem;
  margin-top: auto;
}

/* --- CV Floating Button --- */
.cv-button {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: var(--color-accent);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
  transition: background-color 0.2s ease, transform 0.2s ease;
  text-decoration: none;
  z-index: 999;
}

.cv-button:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-2px);
  text-decoration: none;
  color: #fff;
}

.cv-button svg {
  width: 24px;
  height: 24px;
  fill: currentColor;
}

.cv-button .cv-tooltip {
  position: absolute;
  right: 68px;
  background-color: var(--color-heading);
  color: #fff;
  padding: 6px 12px;
  border-radius: 4px;
  font-size: 0.8rem;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.cv-button:hover .cv-tooltip {
  opacity: 1;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-header-bg);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
  }

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

  .nav-links a {
    padding: 10px 14px;
  }

  .profile-section {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 24px;
  }

  .social-icons {
    justify-content: center;
  }

  .profile-photo {
    width: 160px;
    height: 160px;
  }

  .main-content {
    padding: 32px 16px;
  }

  .site-title {
    font-size: 1rem;
  }

  .cv-button {
    bottom: 20px;
    right: 20px;
    width: 48px;
    height: 48px;
  }
}

@media (max-width: 480px) {
  .profile-photo {
    width: 130px;
    height: 130px;
  }

  .page-header h1 {
    font-size: 1.5rem;
  }

  .section-heading {
    font-size: 1.25rem;
  }
}