/* ============================================================
   Clipboard+ Landing Page — style.css
   カラーパレット: 紺 #0d1a2c / アズール #0b9cf4 / シアン #4ec5f2
   ダーク基調
   ============================================================ */

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

:root {
  --color-bg:        #0d1a2c;
  --color-surface:   #122138;
  --color-surface2:  #1a2e48;
  --color-border:    #1e3a5c;
  --color-azure:     #0b9cf4;
  --color-cyan:      #4ec5f2;
  --color-text:      #e8f0f8;
  --color-text-muted:#8aaabf;
  --color-white:     #ffffff;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;

  --font-body: -apple-system, BlinkMacSystemFont, "Helvetica Neue", Helvetica, Arial, sans-serif;
  --max-w: 1000px;
  --section-gap: 80px;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-cyan);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

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

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

section {
  padding: var(--section-gap) 0;
}

/* ---------- Navigation ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 26, 44, 0.92);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.nav-brand {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-white);
  letter-spacing: -0.02em;
}
.nav-brand span {
  color: var(--color-cyan);
}

.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
}
.nav-links a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  transition: color 0.2s;
}
.nav-links a:hover {
  color: var(--color-cyan);
  text-decoration: none;
}

/* ---------- Hero ---------- */
.hero {
  padding: 100px 0 80px;
  text-align: center;
}

.hero-icon {
  width: 120px;
  height: 120px;
  border-radius: 28px;
  margin: 0 auto 32px;
  box-shadow: 0 8px 40px rgba(11, 156, 244, 0.3);
}

.hero h1 {
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.15;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--color-white) 40%, var(--color-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-catch {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--color-text-muted);
  max-width: 560px;
  margin: 0 auto 36px;
}

.hero-cta-group {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: linear-gradient(135deg, var(--color-azure), var(--color-cyan));
  color: var(--color-white);
  font-size: 1.1rem;
  font-weight: 700;
  padding: 16px 40px;
  border-radius: var(--radius-lg);
  box-shadow: 0 4px 24px rgba(11, 156, 244, 0.45);
  transition: transform 0.18s, box-shadow 0.18s;
}
.btn-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(11, 156, 244, 0.6);
  text-decoration: none;
}
.btn-download svg {
  flex-shrink: 0;
}

.hero-meta {
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

/* ---------- Features ---------- */
.features {
  background: var(--color-surface);
}

.section-title {
  text-align: center;
  font-size: clamp(1.6rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 48px;
}
.section-title span {
  color: var(--color-cyan);
}

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

.card {
  background: var(--color-surface2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  transition: border-color 0.2s, transform 0.2s;
}
.card:hover {
  border-color: var(--color-azure);
  transform: translateY(-3px);
}

.card-icon {
  font-size: 2rem;
  margin-bottom: 14px;
  line-height: 1;
}

.card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-white);
}

.card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ---------- How to Use ---------- */
.howto-steps {
  display: flex;
  gap: 0;
  align-items: flex-start;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
}

.step {
  flex: 1 1 200px;
  max-width: 260px;
  text-align: center;
  position: relative;
}

.step-num {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-azure), var(--color-cyan));
  color: var(--color-white);
  font-size: 1.2rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  box-shadow: 0 4px 16px rgba(11, 156, 244, 0.4);
}

.step h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-white);
}

.step p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
}

.step-arrow {
  flex: 0 0 auto;
  align-self: center;
  color: var(--color-border);
  font-size: 1.5rem;
  margin: 0 4px;
  padding-bottom: 40px;
}

/* ---------- Privacy & Security ---------- */
.security {
  background: var(--color-surface);
}

.security-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.security-item {
  background: var(--color-surface2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 24px;
}

.security-item h3 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--color-cyan);
  margin-bottom: 8px;
}

.security-item p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

.security-item.caution {
  border-color: #3a4a2c;
  background: #1a2218;
}
.security-item.caution h3 {
  color: #a0cc60;
}

.caveat-box {
  margin-top: 28px;
  background: var(--color-surface2);
  border: 1px solid var(--color-border);
  border-left: 4px solid var(--color-azure);
  border-radius: var(--radius-sm);
  padding: 16px 20px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}
.caveat-box strong {
  color: var(--color-text);
}

/* ---------- Support ---------- */
.support-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}

.support-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
}

.support-card h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 12px;
}

.support-card p, .support-card li {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}

.support-card ul {
  margin: 8px 0 0 20px;
}
.support-card li {
  margin-bottom: 6px;
}

.btn-outline {
  display: inline-block;
  margin-top: 16px;
  padding: 10px 24px;
  border: 1.5px solid var(--color-azure);
  border-radius: var(--radius-md);
  color: var(--color-azure);
  font-size: 0.9rem;
  font-weight: 600;
  transition: background 0.18s, color 0.18s;
}
.btn-outline:hover {
  background: var(--color-azure);
  color: var(--color-white);
  text-decoration: none;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 40px 0;
  text-align: center;
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  list-style: none;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.footer-links a {
  color: var(--color-text-muted);
  transition: color 0.2s;
}
.footer-links a:hover {
  color: var(--color-cyan);
  text-decoration: none;
}

.footer-note {
  margin-top: 8px;
  font-size: 0.78rem;
  opacity: 0.6;
}

/* ---------- Sub-page (support / privacy) ---------- */
.subpage-header {
  padding: 60px 0 40px;
  border-bottom: 1px solid var(--color-border);
}
.subpage-header h1 {
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 8px;
}
.subpage-header p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

.subpage-body {
  padding: 48px 0 80px;
  max-width: 720px;
}

.subpage-body h2 {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-cyan);
  margin: 36px 0 10px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--color-border);
}

.subpage-body h2:first-child {
  margin-top: 0;
}

.subpage-body p {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  margin-bottom: 12px;
  line-height: 1.75;
}

.subpage-body ul {
  margin: 6px 0 14px 22px;
}
.subpage-body li {
  font-size: 0.92rem;
  color: var(--color-text-muted);
  margin-bottom: 6px;
  line-height: 1.65;
}

.subpage-body strong {
  color: var(--color-text);
}

.subpage-body .notice-box {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-left: 4px solid #a0cc60;
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  margin: 16px 0;
  font-size: 0.87rem;
  color: var(--color-text-muted);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 40px;
  color: var(--color-text-muted);
  font-size: 0.88rem;
  transition: color 0.2s;
}
.back-link:hover {
  color: var(--color-cyan);
  text-decoration: none;
}

/* ---------- kbd badge ---------- */
kbd {
  display: inline-block;
  background: var(--color-surface2);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 2px 7px;
  font-size: 0.85em;
  font-family: var(--font-body);
  color: var(--color-cyan);
  vertical-align: middle;
}

/* ---------- Responsive ---------- */
@media (max-width: 700px) {
  .nav-links {
    gap: 16px;
  }
  .nav-links a {
    font-size: 0.82rem;
  }

  .security-grid,
  .support-content {
    grid-template-columns: 1fr;
  }

  .step-arrow {
    display: none;
  }

  .howto-steps {
    flex-direction: column;
    align-items: center;
  }

  .step {
    max-width: 100%;
    width: 100%;
  }
}

@media (max-width: 480px) {
  .nav-brand {
    font-size: 1rem;
  }
  .nav-links {
    display: none;
  }
  .hero {
    padding: 64px 0 56px;
  }
  .hero-icon {
    width: 88px;
    height: 88px;
  }
  .btn-download {
    font-size: 1rem;
    padding: 14px 28px;
  }
}