/* ============================================
   style.css — Kotaro Hataguchi Portfolio
   ============================================ */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;700&family=Inter:wght@300;400;500;600;700&display=swap');

/* ---------- CSS Variables ---------- */
:root {
  --color-bg: #ffffff;
  --color-text: #111111;
  --color-text-sub: #555555;
  --color-text-muted: #888888;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-accent-light: #eff6ff;
  --color-accent-mid: #dbeafe;
  --color-border: #e5e7eb;
  --color-surface: #f8f9fa;
  --color-dark: #0f172a;
  --font-en: 'Inter', sans-serif;
  --font-ja: 'Noto Sans JP', sans-serif;
  --max-width: 760px;
  --section-gap: 96px;
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-ja);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

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

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

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

ul {
  list-style: none;
}

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

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

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

/* ---------- Section Labels ---------- */
.section-label {
  font-family: var(--font-en);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 12px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.section-label::before {
  content: '';
  display: inline-block;
  width: 20px;
  height: 2px;
  background-color: var(--color-accent);
  border-radius: 1px;
  flex-shrink: 0;
}

.section-title {
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--color-text);
  margin-bottom: 40px;
  padding-bottom: 16px;
  border-bottom: 2px solid var(--color-accent-mid);
  position: relative;
}

.section-title::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 40px;
  height: 2px;
  background-color: var(--color-accent);
  border-radius: 1px;
}

/* ---------- 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);
}

/* ============================================
   HEADER
   ============================================ */
#header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition);
}

#header.scrolled {
  box-shadow: 0 2px 16px rgba(0, 0, 0, 0.06);
}

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

.header-logo {
  font-family: var(--font-en);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--color-text);
  white-space: nowrap;
}

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

/* Desktop Nav */
.header-nav {
  display: flex;
  align-items: center;
  gap: 32px;
}

.header-nav a {
  font-family: var(--font-ja);
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-sub);
  transition: color var(--transition);
}

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

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 28px;
  height: 28px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 110;
}

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

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

.hamburger.open span:nth-child(2) {
  opacity: 0;
}

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

/* Mobile Menu */
.mobile-menu {
  display: none;
  position: fixed;
  inset: 0;
  top: 64px;
  background-color: var(--color-bg);
  z-index: 99;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 40px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition);
}

.mobile-menu.open {
  display: flex;
  opacity: 1;
  pointer-events: all;
}

.mobile-menu a {
  font-size: 1.3rem;
  font-weight: 500;
  color: var(--color-text);
  transition: color var(--transition);
}

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

/* ============================================
   HERO
   ============================================ */
#hero {
  padding-top: 160px;
  padding-bottom: 120px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
  border-top: 3px solid var(--color-accent);
  min-height: 100vh;
  display: flex;
  align-items: center;
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(160deg, rgba(8,18,55,0.85) 0%, rgba(12,25,70,0.78) 50%, rgba(5,15,45,0.88) 100%),
    url('images/hero-bg.png') center / cover no-repeat;
}

/* 背景デコレーション文字 */
#hero::before {
  content: 'KOTARO';
  position: absolute;
  right: -10px;
  bottom: -10px;
  font-family: var(--font-en);
  font-size: clamp(90px, 25vw, 220px);
  font-weight: 900;
  letter-spacing: -0.06em;
  color: rgba(255, 255, 255, 0.06);
  white-space: nowrap;
  pointer-events: none;
  user-select: none;
  line-height: 0.85;
}

/* 右上のドットパターン装飾 */
#hero::after {
  content: '';
  position: absolute;
  top: 80px;
  right: 0;
  width: 180px;
  height: 180px;
  background-image: radial-gradient(circle, rgba(255,255,255,0.2) 1.5px, transparent 1.5px);
  background-size: 16px 16px;
  mask-image: radial-gradient(ellipse 100% 100% at 100% 0%, black 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 100% 100% at 100% 0%, black 30%, transparent 75%);
}

.hero-inner {
  width: 100%;
  position: relative;
  z-index: 1;
}

/* ピル型バッジ */
.hero-tag {
  font-family: var(--font-en);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: #93c5fd;
  background-color: rgba(255,255,255,0.08);
  border: 1.5px solid rgba(147,197,253,0.4);
  padding: 6px 16px;
  border-radius: 40px;
  margin-bottom: 28px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.hero-tag::before {
  content: '';
  display: inline-block;
  width: 7px;
  height: 7px;
  background-color: #60a5fa;
  border-radius: 50%;
  flex-shrink: 0;
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50%       { opacity: 0.45; transform: scale(0.75); }
}

.hero-title {
  font-size: clamp(1.9rem, 5.5vw, 3rem);
  font-weight: 700;
  line-height: 1.5;
  color: #ffffff;
  margin-bottom: 28px;
  letter-spacing: -0.01em;
}

/* タイトル内の強調パーツ — グラデーションテキスト */
.hero-accent {
  font-style: normal;
  background: linear-gradient(100deg, #2563eb 0%, #3b82f6 50%, #60a5fa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  position: relative;
  white-space: nowrap;
}

.hero-accent::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--color-accent), #60a5fa);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  animation: underline-in 0.6s 0.8s ease forwards;
}

@keyframes underline-in {
  to { transform: scaleX(1); }
}

.hero-sub {
  font-size: 0.95rem;
  color: rgba(255,255,255,0.75);
  line-height: 1.9;
  max-width: 560px;
  margin-bottom: 44px;
  padding: 14px 18px;
  background-color: rgba(255,255,255,0.07);
  border-left: 3px solid rgba(96,165,250,0.7);
  border-radius: 0 4px 4px 0;
  backdrop-filter: blur(4px);
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, #2563eb 0%, #1d4ed8 100%);
  color: #ffffff;
  font-size: 0.92rem;
  font-weight: 600;
  padding: 15px 36px;
  border-radius: 4px;
  letter-spacing: 0.04em;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.45), 0 0 0 0 rgba(37,99,235,0.3);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  position: relative;
  overflow: hidden;
}

/* シマーアニメーション */
.hero-cta::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 60%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.25), transparent);
  animation: shimmer 2.4s ease-in-out infinite;
}

@keyframes shimmer {
  0%   { left: -100%; }
  60%, 100% { left: 150%; }
}

.hero-cta:hover {
  background: linear-gradient(135deg, #1d4ed8 0%, #1e40af 100%);
  color: #ffffff;
  transform: translateY(-3px);
  box-shadow: 0 10px 32px rgba(37, 99, 235, 0.55);
}

.hero-cta svg {
  width: 16px;
  height: 16px;
  transition: transform var(--transition);
}

.hero-cta:hover svg {
  transform: translateX(4px);
}

/* スクロール誠導 */
.hero-scroll {
  position: absolute;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  z-index: 1;
}

.hero-scroll-label {
  font-family: var(--font-en);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.45);
}

.hero-scroll-line {
  display: block;
  width: 1.5px;
  height: 40px;
  background: linear-gradient(to bottom, var(--color-accent), transparent);
  border-radius: 1px;
  animation: scroll-line 1.8s ease-in-out infinite;
}

@keyframes scroll-line {
  0%   { transform: scaleY(0); transform-origin: top; opacity: 1; }
  50%  { transform: scaleY(1); transform-origin: top; opacity: 1; }
  51%  { transform-origin: bottom; }
  100% { transform: scaleY(0); transform-origin: bottom; opacity: 0.3; }
}

/* ============================================
   ABOUT
   ============================================ */
#about {
  background-color: var(--color-accent-light);
}

#about .about-text {
  font-size: 1rem;
  color: var(--color-text-sub);
  line-height: 2;
  padding: 28px 32px;
  background-color: #ffffff;
  border-radius: 6px;
  border-left: 4px solid var(--color-accent);
  box-shadow: 0 2px 12px rgba(37, 99, 235, 0.06);
  margin-bottom: 20px;
}

/* アバター */
.about-avatar {
  display: flex;
  justify-content: center;
  margin-bottom: 28px;
}

.about-avatar-img {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  background-color: #ffffff;
  border: 3px solid var(--color-accent-mid);
  box-shadow:
    0 0 0 6px var(--color-accent-light),
    0 8px 24px rgba(37, 99, 235, 0.15);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.about-avatar-img:hover {
  transform: scale(1.05);
  box-shadow:
    0 0 0 6px var(--color-accent-mid),
    0 12px 32px rgba(37, 99, 235, 0.25);
}

/* ============================================
   SKILLS
   ============================================ */
.skills-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

.skill-item {
  padding: 24px 28px;
  background-color: var(--color-accent-light);
  border: 1px solid var(--color-accent-mid);
  border-left: 4px solid var(--color-accent);
  border-radius: 6px;
  transition: background-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.skill-item:hover {
  background-color: #e0edff;
  box-shadow: 0 4px 20px rgba(37, 99, 235, 0.1);
  transform: translateX(4px);
}

.skill-name {
  font-family: var(--font-en);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-accent);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.skill-name::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--color-accent);
  flex-shrink: 0;
}

.skill-desc {
  font-size: 0.88rem;
  color: var(--color-text-sub);
  padding-left: 16px;
}

/* ============================================
   WORKS
   ============================================ */
.works-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.work-card {
  border: 1px solid var(--color-border);
  border-radius: 6px;
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.work-card:hover {
  border-color: var(--color-accent);
  box-shadow: 0 8px 32px rgba(37, 99, 235, 0.08);
  transform: translateY(-4px);
}

.work-thumb {
  width: 100%;
  aspect-ratio: 16 / 9;
  background-color: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  cursor: pointer;
  text-decoration: none;
}

.work-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}

.work-card:hover .work-thumb img {
  transform: scale(1.04);
}

.work-thumb-placeholder {
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #e8ecf0 0%, #d1d9e3 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--color-text-muted);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
}

.work-thumb-placeholder svg {
  width: 36px;
  height: 36px;
  opacity: 0.4;
}

.work-body {
  padding: 16px 20px;
}

.work-title {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 6px;
  line-height: 1.4;
}

.work-desc {
  font-size: 0.78rem;
  color: var(--color-text-sub);
  margin-bottom: 12px;
  line-height: 1.65;
}

.work-tech {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tech-tag {
  font-family: var(--font-en);
  font-size: 0.72rem;
  font-weight: 500;
  background-color: #eff6ff;
  color: var(--color-accent);
  border: 1px solid #bfdbfe;
  padding: 3px 10px;
  border-radius: 20px;
  letter-spacing: 0.04em;
}

/* ============================================
   STRENGTH
   ============================================ */
.strength-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.strength-item {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  padding: 24px 28px;
  background-color: var(--color-accent-light);
  border: 1px solid var(--color-accent-mid);
  border-radius: 6px;
  transition: box-shadow var(--transition), transform var(--transition);
}

.strength-item:hover {
  box-shadow: 0 4px 16px rgba(37, 99, 235, 0.09);
  transform: translateY(-2px);
}

.strength-number {
  font-family: var(--font-en);
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--color-accent);
  opacity: 0.35;
  line-height: 1;
  flex-shrink: 0;
  min-width: 44px;
  letter-spacing: -0.04em;
}

.strength-content {}

.strength-title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 6px;
}

.strength-desc {
  font-size: 0.875rem;
  color: var(--color-text-sub);
  line-height: 1.8;
}

/* ============================================
   CONTACT
   ============================================ */
#contact {
  background-color: var(--color-accent-light);
}

#contact .contact-lead {
  font-size: 0.95rem;
  color: var(--color-text-sub);
  margin-bottom: 40px;
  line-height: 1.85;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-text);
  letter-spacing: 0.02em;
}

.form-label .required {
  color: var(--color-accent);
  margin-left: 4px;
  font-size: 0.75rem;
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 12px 16px;
  font-family: var(--font-ja);
  font-size: 0.95rem;
  color: var(--color-text);
  background-color: #ffffff;
  border: 1px solid var(--color-accent-mid);
  border-radius: 4px;
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.form-textarea {
  min-height: 160px;
  resize: vertical;
  line-height: 1.8;
}

.form-submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background-color: var(--color-accent);
  color: #ffffff;
  font-family: var(--font-ja);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 14px 40px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  letter-spacing: 0.04em;
  align-self: flex-start;
  transition: background-color var(--transition), transform var(--transition);
}

.form-submit:hover {
  background-color: var(--color-accent-hover);
  transform: translateY(-2px);
}

.form-submit:active {
  transform: translateY(0);
}

/* ============================================
   FOOTER
   ============================================ */
#footer {
  padding: 48px 0;
  text-align: center;
  background-color: var(--color-dark);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.footer-name {
  font-family: var(--font-en);
  font-size: 0.95rem;
  font-weight: 600;
  color: #ffffff;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
}

.footer-copy {
  font-family: var(--font-en);
  font-size: 0.75rem;
  color: rgba(255,255,255,0.35);
  letter-spacing: 0.04em;
}

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 640px) {
  :root {
    --section-gap: 64px;
  }

  .header-nav {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  .hero-title {
    font-size: 1.75rem;
  }

  .hero-sub {
    font-size: 0.88rem;
    padding: 12px 14px;
  }

  /* モバイルではドットパターンを控えめに */
  #hero::after {
    width: 100px;
    height: 100px;
    top: 70px;
  }

  .hero-scroll {
    bottom: 20px;
  }

  .hero-scroll-line {
    height: 28px;
  }

  .section-title {
    font-size: 1.35rem;
  }

  .skills-grid {
    gap: 16px;
  }

  .skill-item {
    padding: 20px 20px;
  }

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

  .work-body {
    padding: 14px 16px;
  }

  .form-submit {
    width: 100%;
  }
}