/* CSS Variables - Japanese Minimalist Theme */
:root {
  --bg-color: #faf9f6; /* Soft white/off-white */
  --text-primary: #2d2d2d; /* Charcoal */
  --text-secondary: #5c5c5c; /* Subtle gray */
  --accent-red: #bc002d; /* Japanese Flag Red */
  --accent-hover: #990022;
  --bg-light: #ffffff;
  --border-color: #eaeaea;
  
  --font-main: 'Inter', sans-serif;
  --font-ja: 'Noto Sans JP', sans-serif;
  
  --transition: all 0.4s ease;
}

/* Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-main);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

.section-padding {
  padding: 6rem 0;
}

/* Typography Details */
h1, h2, h3, h4 {
  font-weight: 500;
  letter-spacing: -0.02em;
}

.accent-text {
  color: var(--accent-red);
}

.accent-dot {
  color: var(--accent-red);
  font-weight: bold;
}

.ja-nav, .ja-section-title, .ja-tagline, .ja-footer {
  font-family: var(--font-ja);
  color: var(--text-secondary);
}

.ja-nav {
  display: block;
  font-size: 0.65rem;
  letter-spacing: 0.05em;
  opacity: 0;
  transform: translateY(-5px);
  transition: var(--transition);
}

.nav-links a:hover .ja-nav {
  opacity: 1;
  transform: translateY(0);
}

.ja-section-title {
  font-size: 0.9rem;
  font-weight: 300;
  margin-left: 1rem;
  opacity: 0.6;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 400;
  transition: var(--transition);
  cursor: pointer;
  border: 1px solid transparent;
  font-size: 0.95rem;
}

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

.btn-primary:hover {
  background-color: var(--accent-red);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(188, 0, 45, 0.15);
}

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

.btn-secondary:hover {
  background-color: var(--bg-light);
  transform: translateY(-2px);
}

.btn-outline {
  border-color: var(--accent-red);
  color: var(--accent-red);
  padding: 0.5rem 1.25rem;
}

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

.btn-block {
  display: block;
  width: 100%;
  text-align: center;
}

/* Resume Nav Section (Blue Theme) */
.nav-resume-section {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.3rem;
}

.nav-resume-heading {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-primary);
  letter-spacing: 0.02em;
}

.nav-resume-buttons {
  display: flex;
  gap: 0.5rem;
}

.resume-action-btn {
  border: 2px solid var(--accent-red);
  color: var(--accent-red);
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.3s ease;
  background: rgba(188, 0, 45, 0.04);
  box-shadow: 0 2px 4px rgba(188, 0, 45, 0.1);
}

.resume-action-btn:hover {
  background-color: var(--accent-red);
  color: #fff;
  transform: translateY(-3px);
  box-shadow: 0 6px 16px rgba(188, 0, 45, 0.25);
}

.btn-icon {
  font-size: 1.1em;
}

/* Navigation */
.navbar {
  position: fixed;
  top: 0;
  width: 100%;
  padding: 1.5rem 0;
  z-index: 1000;
  transition: var(--transition);
  background: transparent;
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 1rem 0;
  box-shadow: 0 1px 0 rgba(0, 0, 0, 0.05);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 2rem;
}

.logo {
  font-size: 1.25rem;
  font-weight: 500;
  text-decoration: none;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 2.5rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-primary);
  font-size: 0.9rem;
  text-align: center;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  width: 0;
  height: 1px;
  bottom: -4px;
  left: 0;
  background-color: var(--accent-red);
  transition: width 0.3s ease;
}

.nav-links a:hover::after {
  width: 100%;
}

/* Hero Section */
.hero {
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  padding: 0 2rem;
  background-image: 
    linear-gradient(to bottom, rgba(250, 249, 246, 0.65), var(--bg-color)),
    url('https://images.unsplash.com/photo-1480796927426-f609979314bd?auto=format&fit=crop&w=2070&q=80'); /* Mount Fuji & Japanese Architecture */
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
}

.hero-content {
  max-width: 800px;
}

.ja-tagline {
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
  font-weight: 300;
}

.title {
  font-size: 4rem;
  margin-bottom: 1rem;
  line-height: 1.1;
  color: var(--text-primary);
}

.subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  font-weight: 300;
  margin-bottom: 2.5rem;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 1rem;
}

.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  opacity: 0.6;
}

.scroll-line {
  width: 1px;
  height: 40px;
  background: var(--text-primary);
  position: relative;
  overflow: hidden;
}

.scroll-line::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 50%;
  background: var(--accent-red);
  animation: scrollAnim 2s infinite ease-in-out;
}

@keyframes scrollAnim {
  0% { transform: translateY(-100%); }
  100% { transform: translateY(200%); }
}

.scroll-text {
  font-family: var(--font-ja);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
}

/* Sections Common */
.section-title {
  font-size: 2rem;
  margin-bottom: 3rem;
  text-align: center;
  display: flex;
  align-items: baseline;
  justify-content: center;
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -10px;
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 1px;
  background-color: var(--accent-red);
}

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

/* About Section */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.about-text p {
  margin-bottom: 1.5rem;
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.about-stats {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.stat-card {
  padding: 2rem;
  border: 1px solid var(--border-color);
  background: var(--bg-light);
  transition: var(--transition);
  text-align: center;
}

.stat-card:hover {
  border-color: var(--accent-red);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.03);
  transform: translateY(-5px);
}

.stat-card h3 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--accent-red);
}

.stat-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Skills Section */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
}

.skill-category {
  padding: 2rem;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  transition: var(--transition);
}

.skill-category:hover {
  border-color: var(--text-primary);
  box-shadow: 0 10px 30px rgba(0,0,0,0.02);
}

.skill-category h3 {
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
  position: relative;
  display: inline-block;
}

.skill-category h3::after {
  content: '';
  position: absolute;
  width: 20px;
  height: 1px;
  background: var(--accent-red);
  bottom: -5px;
  left: 0;
}

.skill-list {
  list-style: none;
}

.skill-list li {
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
  position: relative;
  padding-left: 1rem;
}

.skill-list li::before {
  content: '•';
  color: var(--accent-red);
  position: absolute;
  left: 0;
}

/* Projects Section */
.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
  gap: 3rem;
}

.project-card {
  background: var(--bg-light);
  border: 1px solid var(--border-color);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.project-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: var(--accent-red);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.5s ease;
}

.project-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 40px rgba(0,0,0,0.04);
}

.project-card:hover::before {
  transform: scaleX(1);
}

.project-content {
  padding: 3rem 2rem;
}

.project-badge {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-red);
  display: block;
  margin-bottom: 0.5rem;
}

.project-content h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.project-content p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

.project-highlights {
  list-style: none;
  margin-bottom: 2rem;
}

.project-highlights li {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
  padding-left: 1rem;
  position: relative;
}

.project-highlights li::before {
  content: '-';
  position: absolute;
  left: 0;
  color: var(--text-primary);
}

.project-tools {
  display: flex;
  gap: 1rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
}

.project-tools span {
  font-size: 0.8rem;
  color: var(--text-secondary);
  background: var(--bg-color);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
}

/* Education Timeline */
.timeline {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 1px;
  background: var(--border-color);
}

.timeline-item {
  position: relative;
  padding-left: 3rem;
  margin-bottom: 3rem;
}

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

.timeline-dot {
  position: absolute;
  left: -4px;
  top: 0;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent-red);
  border: 2px solid var(--bg-light);
}

.timeline-date {
  font-size: 0.85rem;
  color: var(--accent-red);
  font-weight: 500;
  display: block;
  margin-bottom: 0.5rem;
}

.timeline-content h3 {
  font-size: 1.25rem;
  margin-bottom: 0.25rem;
}

.timeline-institution {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Contact Section */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
}

.contact-desc {
  color: var(--text-secondary);
  margin-bottom: 2rem;
  font-size: 1.05rem;
}

.contact-details {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  text-decoration: none;
  color: var(--text-primary);
  font-size: 1rem;
  transition: var(--transition);
}

.contact-item:hover {
  color: var(--accent-red);
}

.contact-icon {
  font-size: 1.25rem;
  opacity: 0.8;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 1rem;
  border: 1px solid var(--border-color);
  background: var(--bg-light);
  font-family: inherit;
  font-size: 1rem;
  color: var(--text-primary);
  transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--text-primary);
}

/* Footer */
.footer {
  padding: 4rem 2rem;
  background: var(--bg-light);
  border-top: 1px solid var(--border-color);
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.footer p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-subtext {
  font-size: 0.75rem;
  font-family: var(--font-main);
  opacity: 0.5;
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2.5rem;
  right: 2.5rem;
  background-color: var(--accent-red);
  color: #ffffff;
  border: none;
  padding: 1.25rem 0.5rem;
  writing-mode: vertical-rl;
  text-orientation: upright;
  font-family: var(--font-ja);
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.3rem;
  text-decoration: none;
  opacity: 0;
  pointer-events: none;
  transform: translateY(20px);
  transition: var(--transition);
  z-index: 999;
  border-radius: 4px;
  box-shadow: 0 4px 15px rgba(188, 0, 45, 0.3);
}

.back-to-top.show {
  opacity: 1 !important;
  pointer-events: auto !important;
  transform: translateY(0) !important;
}

.back-to-top.show:hover {
  background-color: var(--text-primary);
  color: #ffffff;
  transform: translateY(-8px) !important;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.25);
}

/* Animations */
.fade-in-section {
  opacity: 0;
  transform: translateY(2vh);
  visibility: hidden;
  transition: opacity 0.8s ease-out, transform 0.8s ease-out;
  will-change: opacity, visibility;
}

.fade-in-section.is-visible {
  opacity: 1;
  transform: none;
  visibility: visible;
}

/* Responsive Design */
@media (max-width: 900px) {
  .about-grid, .contact-grid {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  
  .title {
    font-size: 3rem;
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none; /* simple mobile hide for a minimal site */
  }

  .nav-resume-buttons {
    flex-direction: column;
    gap: 0.4rem;
  }

  .nav-resume-section {
    align-items: flex-end;
  }
  
  .project-grid {
    grid-template-columns: 1fr;
  }
  
  .section-padding {
    padding: 4rem 0;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
  }
  
  .title {
    font-size: 2.5rem;
  }
}