:root {
  --brand-50: #eef5ff;
  --brand-100: #d9e8ff;
  --brand-500: #2468ff;
  --brand-600: #154fdb;
  --brand-700: #123fac;
  --slate-50: #f8fafc;
  --slate-100: #f1f5f9;
  --slate-200: #e2e8f0;
  --slate-300: #cbd5e1;
  --slate-400: #94a3b8;
  --slate-500: #64748b;
  --slate-600: #475569;
  --slate-900: #0f172a;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Kaku Gothic ProN", "Noto Sans JP", sans-serif;
  color: var(--slate-900);
  background: var(--slate-50);
}
a { color: inherit; text-decoration: none; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,0.9);
  border-bottom: 1px solid var(--slate-200);
  backdrop-filter: blur(6px);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; padding: 12px 20px; }
.logo { display: flex; align-items: center; gap: 8px; font-weight: 700; }
.logo-badge {
  display: flex; align-items: center; justify-content: center;
  width: 32px; height: 32px; border-radius: 8px;
  background: var(--brand-500); color: #fff; font-size: 14px;
}
.logo-text { font-size: 18px; }
.logo-accent { color: var(--brand-500); }
.nav-links { display: none; gap: 24px; font-size: 14px; font-weight: 500; color: var(--slate-600); }
@media (min-width: 640px) { .nav-links { display: flex; } }
.nav-links a:hover { color: var(--brand-600); }

.btn {
  display: inline-block; border-radius: 8px; font-weight: 600; text-align: center;
  cursor: pointer; border: 1px solid transparent;
}
.btn-primary { background: var(--brand-500); color: #fff; }
.btn-primary:hover { background: var(--brand-600); }
.btn-outline { background: #fff; border-color: var(--slate-300); color: var(--slate-600); }
.btn-outline:hover { background: var(--slate-50); }
.btn-danger-outline { background: #fff; border-color: #fca5a5; color: #dc2626; }
.btn-danger-outline:hover { background: #fef2f2; }
.btn-small { padding: 8px 16px; font-size: 14px; }
.btn-medium { padding: 10px 20px; font-size: 15px; }
.btn-large { padding: 14px 32px; font-size: 16px; }
.btn-block { display: block; width: 100%; }
.btn:disabled, .btn.disabled { background: var(--slate-300); color: #fff; cursor: not-allowed; }

.hero { background: linear-gradient(to bottom, var(--brand-50), #fff); text-align: center; padding: 80px 20px; }
.hero-badge { display: inline-block; background: var(--brand-100); color: var(--brand-700); font-weight: 600; font-size: 14px; padding: 4px 16px; border-radius: 999px; }
.hero h1 { font-size: 36px; font-weight: 800; margin: 24px 0; line-height: 1.3; }
@media (min-width: 640px) { .hero h1 { font-size: 48px; } }
.hero p { max-width: 640px; margin: 0 auto; color: var(--slate-600); font-size: 18px; }
.hero-actions { display: flex; flex-direction: column; gap: 12px; justify-content: center; margin-top: 40px; }
@media (min-width: 640px) { .hero-actions { flex-direction: row; } }
.hero-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; max-width: 640px; margin: 64px auto 0; text-align: center; }
.hero-stats dt { font-size: 28px; font-weight: 800; color: var(--brand-600); }
@media (min-width: 640px) { .hero-stats dt { font-size: 32px; } }
.hero-stats dd { margin: 4px 0 0; font-size: 14px; color: var(--slate-500); }

section { padding: 80px 20px; }
.section-head { text-align: center; }
.section-head h2 { font-size: 30px; font-weight: 700; }
.section-head p { margin-top: 12px; color: var(--slate-600); }

.features-grid { display: grid; gap: 24px; margin-top: 48px; grid-template-columns: 1fr; }
@media (min-width: 640px) { .features-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 900px) { .features-grid { grid-template-columns: repeat(3, 1fr); } }
.feature-card { background: #fff; border: 1px solid var(--slate-200); border-radius: 16px; padding: 24px; box-shadow: 0 1px 2px rgba(0,0,0,0.04); }
.feature-card .icon { font-size: 30px; }
.feature-card h3 { margin: 16px 0 8px; }
.feature-card p { margin: 0; font-size: 14px; line-height: 1.6; color: var(--slate-600); }

.how-it-works { background: var(--slate-900); color: #fff; }
.how-it-works .section-head p { color: var(--slate-300); }
.steps-grid { display: grid; gap: 32px; margin-top: 48px; grid-template-columns: 1fr; }
@media (min-width: 640px) { .steps-grid { grid-template-columns: repeat(3, 1fr); } }
.step { text-align: center; }
.step-num { width: 48px; height: 48px; border-radius: 999px; background: var(--brand-500); display: flex; align-items: center; justify-content: center; margin: 0 auto; font-weight: 700; }
.step h3 { margin: 16px 0 8px; }
.step p { font-size: 14px; color: var(--slate-300); line-height: 1.6; margin: 0; }

.faq-section { max-width: 720px; margin: 0 auto; }
.faq-item { border: 1px solid var(--slate-200); border-radius: 12px; padding: 20px; background: #fff; margin-top: 16px; }
.faq-item summary { cursor: pointer; font-weight: 600; list-style: none; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-q { color: var(--brand-500); margin-right: 8px; }
.faq-a { margin: 12px 0 0; font-size: 14px; color: var(--slate-600); line-height: 1.6; }

.cta-section { background: var(--brand-50); text-align: center; }
.cta-section h2 { font-size: 24px; font-weight: 700; }

.site-footer { border-top: 1px solid var(--slate-200); background: #fff; margin-top: auto; }
.footer-inner { padding: 40px 20px; }
.footer-grid { display: grid; gap: 32px; grid-template-columns: repeat(2, 1fr); font-size: 14px; color: var(--slate-600); }
@media (min-width: 640px) { .footer-grid { grid-template-columns: repeat(4, 1fr); } }
.footer-grid h3 { margin: 0 0 12px; color: var(--slate-900); font-size: 15px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: 8px; }
.footer-grid a:hover { color: var(--brand-600); }
.footer-bottom { margin-top: 32px; padding-top: 24px; border-top: 1px solid var(--slate-100); font-size: 12px; color: var(--slate-400); }

/* upload / share / manage 共通 */
.page-narrow { max-width: 640px; margin: 0 auto; padding: 48px 20px; }
.page-narrow-wide { max-width: 780px; margin: 0 auto; padding: 48px 20px; }
.card { background: #fff; border: 1px solid var(--slate-200); border-radius: 16px; padding: 24px; box-shadow: 0 1px 2px rgba(0,0,0,0.04); }
.card + .card { margin-top: 16px; }
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 14px; font-weight: 500; margin-bottom: 6px; }
.form-group select, .form-group input[type=text], .form-group input[type=password], .form-group textarea {
  width: 100%; border: 1px solid var(--slate-300); border-radius: 8px; padding: 8px 12px; font-size: 14px; font-family: inherit;
}
.form-group select:focus, .form-group input:focus, .form-group textarea:focus { outline: none; border-color: var(--brand-500); }
.error-text { color: #dc2626; font-size: 14px; }
.helper-text { color: var(--slate-500); font-size: 12px; margin-top: 4px; }

.file-drop {
  border: 2px dashed var(--slate-300); border-radius: 12px; padding: 40px 20px; text-align: center; color: var(--slate-500);
  cursor: pointer; background: #fff;
}
.file-drop.dragover { border-color: var(--brand-500); background: var(--brand-50); }

.file-list { list-style: none; padding: 0; margin: 16px 0 0; }
.file-list li { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 10px 0; border-bottom: 1px solid var(--slate-100); font-size: 14px; }
.file-list .name { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.progress-bar { height: 6px; border-radius: 999px; background: var(--slate-200); overflow: hidden; margin-top: 4px; }
.progress-bar-fill { height: 100%; background: var(--brand-500); width: 0%; transition: width 0.2s; }

.badge { display: inline-block; border-radius: 999px; padding: 2px 10px; font-size: 12px; font-weight: 500; }
.badge-clean { background: #d1fae5; color: #047857; }
.badge-warn { background: #fef3c7; color: #b45309; }
.badge-danger { background: #fee2e2; color: #b91c1c; }
.badge-muted { background: var(--slate-200); color: var(--slate-600); }

.share-file-item { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; padding: 16px; }
.share-file-item .icon { font-size: 24px; }
.share-file-meta { min-width: 0; }
.share-file-meta .name { font-weight: 500; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.share-file-meta .sub { font-size: 13px; color: var(--slate-500); margin-top: 2px; }

.copy-row { display: flex; align-items: center; gap: 8px; background: var(--slate-50); border-radius: 8px; padding: 12px; }
.copy-row .value { flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-family: monospace; font-size: 13px; }

.stat-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; font-size: 14px; margin-top: 24px; }
@media (min-width: 640px) { .stat-grid { grid-template-columns: repeat(3, 1fr); } }
.stat-grid dt { color: var(--slate-500); }
.stat-grid dd { margin: 2px 0 0; font-weight: 600; }

.notice-center { text-align: center; margin-top: 80px; }
.notice-center .emoji { font-size: 48px; }