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

:root {
  --bg: #ffffff;
  --bg-secondary: #f9fafb;
  --fg: #111827;
  --fg-muted: #6b7280;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --danger: #dc2626;
  --danger-hover: #b91c1c;
  --card-bg: #ffffff;
  --card-border: #e5e7eb;
  --input-bg: #f9fafb;
  --input-border: #d1d5db;
  --success: #16a34a;
  --font: 'Inter', 'Noto Sans JP', ui-sans-serif, system-ui, sans-serif;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.08);
  --transition: 200ms ease;
}

.dark {
  --bg: #030712;
  --bg-secondary: #111827;
  --fg: #f3f4f6;
  --fg-muted: #9ca3af;
  --card-bg: #111827;
  --card-border: #1f2937;
  --input-bg: #1f2937;
  --input-border: #374151;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
}

html {
  font-family: var(--font);
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--transition), color var(--transition);
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding-top: 64px;
}

#app {
  display: flex;
  flex-direction: column;
  min-height: calc(100vh - 64px);
}

/* ===== Layout ===== */
.container {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0 1.5rem;
  width: 100%;
}

/* ===== Header ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.8);
  border-bottom: 1px solid rgba(229, 231, 235, 0.5);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: background var(--transition);
}

.dark .header {
  background: rgba(3, 7, 18, 0.8);
  border-bottom-color: rgba(31, 41, 55, 0.5);
}

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

.logo {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--fg);
  text-decoration: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-link {
  font-size: 0.875rem;
  color: var(--fg-muted);
  text-decoration: none;
  transition: color var(--transition);
}

.nav-link:hover {
  color: var(--fg);
}

.btn-icon {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  color: var(--fg-muted);
  transition: background var(--transition), color var(--transition);
  display: flex;
  align-items: center;
}

.btn-icon:hover {
  background: var(--input-bg);
  color: var(--fg);
}

.icon-sun { display: none; }
.icon-moon { display: block; }
.dark .icon-sun { display: block; }
.dark .icon-moon { display: none; }

/* ===== Hero ===== */
.hero {
  padding: 4rem 0 2rem;
  text-align: center;
}

.hero-title {
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 1rem;
}

.hero-title .accent {
  color: var(--accent);
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--fg-muted);
  max-width: 36rem;
  margin: 0 auto 1.5rem;
  line-height: 1.7;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.375rem 0.875rem;
  background: var(--bg-secondary);
  border: 1px solid var(--card-border);
  border-radius: 9999px;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--fg-muted);
  transition: all var(--transition);
}

/* ===== Sections ===== */
.section {
  padding: 2.5rem 0;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  margin-bottom: 0.5rem;
}

.section-desc {
  color: var(--fg-muted);
  margin-bottom: 1.5rem;
}

/* ===== Cards ===== */
.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
  transition: background var(--transition), border-color var(--transition), box-shadow 300ms ease, transform 300ms ease;
}

.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  width: 100%;
  margin-top: 1rem;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--input-bg);
  color: var(--fg);
  border: 1px solid var(--card-border);
}

.btn-secondary:hover {
  background: var(--input-border);
}

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

.btn-danger:hover:not(:disabled) {
  background: var(--danger-hover);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 0.375rem 0.75rem;
  font-size: 0.75rem;
  width: auto;
  margin-top: 0;
}

/* ===== Inputs ===== */
.input {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.875rem;
  color: var(--fg);
  outline: none;
  transition: border-color var(--transition), box-shadow var(--transition);
}

.input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.375rem;
  color: var(--fg);
}

/* ===== Delete Auth Toggle ===== */
.delete-auth-toggle {
  display: flex;
  gap: 0;
  margin-bottom: 1rem;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.toggle-btn {
  flex: 1;
  padding: 0.5rem 1rem;
  border: none;
  background: var(--input-bg);
  color: var(--fg-muted);
  font-family: var(--font);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}

.toggle-btn.active {
  background: var(--accent);
  color: #fff;
}

.toggle-btn:not(.active):hover {
  background: var(--input-border);
}

/* ===== Drop Zone ===== */
.drop-zone {
  border: 2px dashed var(--input-border);
  border-radius: var(--radius);
  padding: 3rem 1.5rem;
  text-align: center;
  cursor: pointer;
  transition: all var(--transition);
  margin-bottom: 1rem;
}

.drop-zone:hover,
.drop-zone.dragover {
  border-color: var(--accent);
  background: rgba(37, 99, 235, 0.04);
}

.drop-icon {
  font-size: 2.5rem;
  display: block;
  margin-bottom: 0.75rem;
}

.text-muted {
  color: var(--fg-muted);
}

.text-sm {
  font-size: 0.75rem;
}

/* ===== File Preview ===== */
.file-preview {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background: var(--input-bg);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.preview-img {
  width: 64px;
  height: 64px;
  object-fit: cover;
  border-radius: var(--radius-sm);
}

.file-info {
  flex: 1;
  min-width: 0;
}

.file-name {
  display: block;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ===== Result Card ===== */
.result-card {
  margin-top: 1.5rem;
  animation: fadeInUp 0.5s ease-out;
}

.result-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--success);
}

.result-field {
  margin-bottom: 1rem;
}

.result-field label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--fg-muted);
  margin-bottom: 0.375rem;
}

.copy-group {
  display: flex;
  gap: 0.5rem;
}

.copy-group .input {
  flex: 1;
  font-size: 0.8125rem;
  font-family: 'Courier New', monospace;
}

/* ===== Footer ===== */
.footer {
  margin-top: auto;
  padding: 2rem 0;
  text-align: center;
  color: var(--fg-muted);
  font-size: 0.875rem;
  border-top: 1px solid var(--card-border);
}

.footer a {
  color: var(--accent);
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}

/* ===== Toast ===== */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 100;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toast {
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: #fff;
  box-shadow: var(--shadow-lg);
  animation: fadeInUp 300ms ease;
  max-width: 360px;
}

.toast-success { background: var(--success); }
.toast-error { background: var(--danger); }
.toast-info { background: var(--accent); }

/* ===== Utilities ===== */
.hidden {
  display: none !important;
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.animate-on-scroll.animate-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .hero-title {
    font-size: 2rem;
  }

  .hero-desc {
    font-size: 1rem;
  }

  .section-title {
    font-size: 1.25rem;
  }

  .copy-group {
    flex-direction: column;
  }

  .copy-group .btn-sm {
    width: 100%;
  }

  .hero-badges {
    gap: 0.375rem;
  }
}

/* --- Reduced Motion --- */
@media (prefers-reduced-motion: reduce) {
  .animate-on-scroll {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .toast,
  .result-card {
    animation: none;
  }
  .card:hover,
  .btn-primary:hover:not(:disabled),
  .btn-danger:hover:not(:disabled) {
    transform: none;
  }
}