/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --blue-deep:  #0077B6;
  --blue-mid:   #00B4D8;
  --blue-light: #90E0EF;
  --blue-pale:  #E8F6FD;
  --navy:       #023E5C;
  --text:       #1A2B3C;
  --muted:      #64748B;
  --line:       #E2EEF5;
  --white:      #FFFFFF;
  --surface:    #F8FBFD;

  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;

  --shadow-sm: 0 2px 8px rgba(0,119,182,0.08);
  --shadow-md: 0 8px 32px rgba(0,119,182,0.12);
  --shadow-lg: 0 16px 48px rgba(0,119,182,0.18);
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Noto Sans JP', sans-serif;
  color: var(--text);
  background: var(--white);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; }
a  { color: inherit; text-decoration: none; }

/* ===== TYPOGRAPHY ===== */
.en-heading {
  font-family: 'Cormorant Garamond', serif;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

h1, h2, h3 { line-height: 1.25; }

/* ===== LAYOUT ===== */
.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 80px 0; }

/* ===== HEADER / NAV ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.site-logo {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.site-logo .en {
  font-family: 'Cormorant Garamond', serif;
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--blue-deep);
  letter-spacing: 0.16em;
}

.site-logo .ja {
  font-size: 0.75rem;
  color: var(--muted);
  letter-spacing: 0.05em;
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--muted);
  transition: color 0.2s;
}

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

/* ===== HERO ===== */
.hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, var(--navy) 0%, var(--blue-deep) 50%, var(--blue-mid) 100%);
  color: var(--white);
  padding: 120px 0 100px;
}

/* water ripple decoration */
.hero::before {
  content: '';
  position: absolute;
  bottom: -40px; left: 0; right: 0;
  height: 80px;
  background: var(--white);
  clip-path: ellipse(55% 100% at 50% 100%);
}

/* floating circles */
.hero-deco {
  position: absolute;
  border-radius: 50%;
  opacity: 0.08;
  pointer-events: none;
}
.hero-deco-1 {
  width: 480px; height: 480px;
  top: -120px; right: -100px;
  background: var(--blue-light);
}
.hero-deco-2 {
  width: 240px; height: 240px;
  bottom: 20px; left: -60px;
  background: var(--white);
}

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

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--blue-light);
  margin-bottom: 20px;
}

.hero-eyebrow::before {
  content: '';
  display: block;
  width: 24px; height: 2px;
  background: var(--blue-light);
}

.hero-main-en {
  font-family: 'Shippori Mincho B1', serif;
  font-size: clamp(2.8rem, 8vw, 6.5rem);
  font-weight: 700;
  letter-spacing: 0.06em;
  line-height: 1.1;
  color: var(--white);
  margin-bottom: 16px;
}

.hero-main-ja {
  font-family: 'Shippori Mincho B1', serif;
  font-size: clamp(1.125rem, 3vw, 1.5rem);
  font-weight: 400;
  color: rgba(255,255,255,0.85);
  letter-spacing: 0.1em;
  margin-bottom: 40px;
}

.hero-desc {
  max-width: 540px;
  font-size: 0.9rem;
  color: rgba(255,255,255,0.75);
  line-height: 1.85;
  border-left: 2px solid var(--blue-light);
  padding-left: 16px;
}

/* ===== NOTICE ===== */
.notice-section {
  background: var(--blue-pale);
  padding: 56px 0;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--blue-deep);
  margin-bottom: 8px;
}

.section-label::before {
  content: '';
  display: block;
  width: 16px; height: 2px;
  background: var(--blue-deep);
}

.section-heading {
  font-family: 'Shippori Mincho B1', serif;
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 32px;
  letter-spacing: 0.08em;
}

.notice-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}

.notice-card {
  background: var(--white);
  border-radius: var(--radius-md);
  padding: 28px 32px;
  display: flex;
  gap: 20px;
  align-items: flex-start;
  box-shadow: var(--shadow-sm);
  border-left: 4px solid var(--blue-mid);
}

.notice-icon {
  width: 44px; height: 44px;
  border-radius: 50%;
  background: var(--blue-pale);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem;
  flex-shrink: 0;
}

.notice-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue-deep);
  margin-bottom: 4px;
}

.notice-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--navy);
  margin-bottom: 4px;
}

.notice-sub {
  font-size: 0.8rem;
  color: var(--muted);
}

/* ===== ASSIGNMENT CARDS ===== */
.assignments-section { background: var(--white); }

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 28px;
  margin-top: 8px;
}

.assignment-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
}

.assignment-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card-banner {
  height: 8px;
  background: linear-gradient(90deg, var(--blue-deep), var(--blue-mid));
}

.card-body { padding: 36px 36px 28px; flex: 1; }

.card-number {
  font-family: 'Noto Sans JP', sans-serif;
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--blue-mid);
  margin-bottom: 12px;
}

.card-title {
  font-family: 'Shippori Mincho B1', serif;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 8px;
  letter-spacing: 0.06em;
}

.card-strokes {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.stroke-tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 100px;
  background: var(--blue-pale);
  color: var(--blue-deep);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
}

.card-meta {
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 4px;
}

.card-footer {
  padding: 20px 36px 28px;
  border-top: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.deadline-badge {
  font-size: 0.75rem;
  color: var(--muted);
}

.deadline-badge strong {
  color: var(--text);
  font-weight: 600;
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 100px;
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--blue-deep);
  color: var(--white);
}

.btn-primary:hover {
  background: var(--navy);
  transform: translateX(2px);
}

.btn-outline {
  background: transparent;
  color: var(--blue-deep);
  border: 2px solid var(--blue-deep);
}

.btn-outline:hover {
  background: var(--blue-pale);
}

.btn-youtube {
  background: #D4B030;
  color: #1A2B3C;
}

.btn-youtube:hover { background: #B89820; }

.btn-form {
  background: #D6BC82;
  color: #1A2B3C;
}

.btn-form:hover { background: #BFA060; }

.btn-lg { padding: 16px 36px; font-size: 1rem; }

/* ===== FAQ ===== */
.faq-section { background: var(--surface); }

.faq-list { max-width: 720px; }

.faq-item {
  border-bottom: 1px solid var(--line);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 24px 0;
  background: none;
  border: none;
  cursor: pointer;
  text-align: left;
  font-family: 'Noto Sans JP', sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--navy);
}

.faq-question .q-mark {
  flex-shrink: 0;
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--blue-pale);
  color: var(--blue-deep);
  display: flex; align-items: center; justify-content: center;
  font-family: 'Oswald', sans-serif;
  font-size: 0.875rem;
  font-weight: 700;
}

.faq-question .faq-chevron {
  flex-shrink: 0;
  font-size: 1rem;
  color: var(--muted);
  transition: transform 0.2s;
}

.faq-item.open .faq-chevron { transform: rotate(180deg); }

.faq-answer {
  display: none;
  padding: 0 0 24px 44px;
  font-size: 0.875rem;
  color: var(--muted);
  line-height: 1.85;
}

.faq-item.open .faq-answer { display: block; }

/* ===== LESSON PAGE ===== */
.lesson-hero {
  background: linear-gradient(135deg, var(--navy) 0%, var(--blue-deep) 100%);
  color: var(--white);
  padding: 80px 0 72px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.65);
  margin-bottom: 24px;
  transition: color 0.2s;
}

.back-link:hover { color: var(--white); }

.lesson-number {
  font-family: 'Noto Sans JP', sans-serif;
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--blue-light);
  margin-bottom: 12px;
}

.lesson-title {
  font-family: 'Shippori Mincho B1', serif;
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 700;
  color: var(--white);
  margin-bottom: 8px;
  letter-spacing: 0.08em;
}

.lesson-subtitle {
  font-size: 1rem;
  color: rgba(255,255,255,0.7);
  letter-spacing: 0.06em;
}

.lesson-body { padding: 72px 0; }

.lesson-layout {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 48px;
  align-items: start;
}

.lesson-section-title {
  font-family: 'Oswald', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue-deep);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.lesson-section-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--line);
}

.lesson-desc {
  font-size: 0.925rem;
  color: var(--muted);
  line-height: 1.9;
  margin-bottom: 40px;
}

/* YouTube embed */
.video-wrap {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: #000;
  margin-bottom: 40px;
}

.video-wrap iframe {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  border: none;
}

.video-placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #0a1628, #0d2b4b);
  color: rgba(255,255,255,0.5);
  gap: 12px;
  font-size: 0.8rem;
  letter-spacing: 0.08em;
}

.video-placeholder .play-icon {
  width: 56px; height: 56px;
  border-radius: 50%;
  border: 2px solid rgba(255,255,255,0.25);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem;
  color: rgba(255,255,255,0.4);
}

/* Sidebar */
.lesson-sidebar { position: sticky; top: 88px; }

.info-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.info-card-header {
  background: linear-gradient(135deg, var(--blue-deep), var(--blue-mid));
  padding: 20px 24px;
  color: var(--white);
  font-family: 'Oswald', sans-serif;
  font-size: 0.8rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.info-card-body { padding: 24px; }

.info-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.85rem;
}

.info-row:last-child { border-bottom: none; }

.info-row .label { color: var(--muted); }

.info-row .value {
  font-weight: 600;
  color: var(--navy);
  text-align: right;
}

.info-row .value.deadline { color: #DC2626; }

.action-buttons {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 20px;
}

/* ===== FOOTER ===== */
.site-footer {
  background: var(--navy);
  color: rgba(255,255,255,0.5);
  padding: 48px 0;
  text-align: center;
}

.footer-logo {
  font-family: 'Cormorant Garamond', serif;
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  color: rgba(255,255,255,0.8);
  margin-bottom: 8px;
}

.footer-copy {
  font-size: 0.75rem;
  letter-spacing: 0.06em;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  section { padding: 56px 0; }

  .nav-links { display: none; }

  .hero { padding: 80px 0 72px; }

  .hero::before { height: 48px; }

  .lesson-layout {
    grid-template-columns: 1fr;
  }

  .lesson-sidebar { position: static; }

  .card-footer {
    flex-direction: column;
    align-items: flex-start;
  }

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

  .action-buttons .btn { justify-content: center; }
}

@media (max-width: 480px) {
  .container { padding: 0 16px; }

  .card-body { padding: 24px 20px 16px; }

  .card-footer { padding: 16px 20px 20px; }

  .info-card-body { padding: 16px; }
}

/* ===== UTILITIES ===== */
.mt-0 { margin-top: 0; }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.text-center { text-align: center; }
.full-width { width: 100%; justify-content: center; }