:root {
  color-scheme: light;
  --bg: #f4f7fb;
  --surface: #ffffff;
  --surface-soft: #eef4fb;
  --text: #172033;
  --muted: #667085;
  --border: #dbe4ef;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-soft: #e8f0ff;
  --danger: #c24141;
  --danger-soft: #fff1f1;
  --success: #13795b;
  --success-soft: #e8f7f1;
  --shadow: 0 18px 50px rgba(30, 64, 175, 0.08);
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0f172a;
  --surface: #172033;
  --surface-soft: #202c42;
  --text: #edf2f7;
  --muted: #9aa9bf;
  --border: #31415a;
  --primary: #60a5fa;
  --primary-hover: #93c5fd;
  --primary-soft: rgba(96, 165, 250, 0.12);
  --danger: #f18b8b;
  --danger-soft: rgba(194, 65, 65, 0.13);
  --success: #6ee7b7;
  --success-soft: rgba(19, 121, 91, 0.16);
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.22);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", sans-serif;
  line-height: 1.65;
}

button,
input {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

a {
  color: inherit;
}

svg {
  display: block;
  flex: 0 0 auto;
}

.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 20;
}

[data-theme="dark"] .site-header {
  background: rgba(15, 23, 42, 0.9);
}

.header-inner,
.container {
  width: min(100% - 32px, 1040px);
  margin-inline: auto;
}

.header-inner {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  font-weight: 750;
  text-decoration: none;
}

.brand-mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  background: var(--primary);
  color: #fff;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.language-link,
.icon-button {
  min-height: 38px;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--surface);
  color: var(--text);
}

.language-link {
  padding: 6px 12px;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}

.icon-button {
  width: 38px;
  padding: 0;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.language-link:hover,
.icon-button:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.container {
  padding-block: 26px 72px;
}

.breadcrumb {
  margin-bottom: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  align-items: center;
  color: var(--muted);
  font-size: 13px;
}

.breadcrumb a {
  text-decoration: none;
}

.breadcrumb a:hover {
  color: var(--primary);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(260px, 0.72fr);
  gap: 48px;
  align-items: end;
  margin: 32px 0 40px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--primary);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 720px;
  margin-bottom: 16px;
  font-size: clamp(34px, 6vw, 58px);
  line-height: 1.08;
  letter-spacing: -0.045em;
  text-wrap: balance;
}

.lead {
  max-width: 660px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: clamp(16px, 2vw, 19px);
}

.privacy-note {
  margin: 0;
  padding: 18px;
  display: flex;
  gap: 13px;
  align-items: flex-start;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--surface);
  box-shadow: var(--shadow);
  color: var(--muted);
  font-size: 14px;
}

.privacy-note svg {
  margin-top: 2px;
  color: var(--success);
}

.privacy-note strong {
  display: block;
  margin-bottom: 3px;
  color: var(--text);
}

.tool-card {
  overflow: hidden;
  border: 1px solid var(--border);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.drop-zone {
  min-height: 238px;
  margin: 18px;
  padding: 34px 22px;
  display: grid;
  place-items: center;
  align-content: center;
  text-align: center;
  border: 1.5px dashed #9db1cc;
  border-radius: 16px;
  background: var(--surface-soft);
  cursor: pointer;
  transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.drop-zone:hover,
.drop-zone.dragover,
.drop-zone:focus-visible {
  border-color: var(--primary);
  background: var(--primary-soft);
  outline: none;
  transform: translateY(-2px);
}

.upload-icon {
  width: 48px;
  height: 48px;
  margin-bottom: 16px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  background: var(--primary);
  color: #fff;
}

.drop-zone h2 {
  margin-bottom: 7px;
  font-size: 20px;
}

.drop-zone p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

#fileInput {
  display: none;
}

.workspace {
  padding: 0 18px 18px;
}

.workspace-header {
  padding: 18px 0 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.workspace-header h2 {
  margin-bottom: 2px;
  font-size: 18px;
}

.workspace-meta {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.file-list {
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
  list-style: none;
}

.output-name {
  margin-top: 16px;
  padding: 14px;
  display: grid;
  grid-template-columns: minmax(120px, auto) minmax(0, 1fr);
  gap: 12px;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface-soft);
}

.output-name label {
  font-size: 14px;
  font-weight: 750;
}

.output-name-field {
  min-width: 0;
  display: flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 9px;
  background: var(--surface);
  transition: border-color 150ms ease, box-shadow 150ms ease;
}

.output-name-field:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.output-name-field input {
  min-width: 0;
  width: 100%;
  padding: 9px 2px 9px 12px;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--text);
}

.file-extension {
  padding: 9px 12px 9px 4px;
  color: var(--muted);
  font-size: 14px;
  user-select: none;
}

.file-row {
  min-width: 0;
  padding: 12px;
  display: grid;
  grid-template-columns: auto auto minmax(0, 1fr) auto;
  gap: 12px;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface-soft);
  transition: border-color 160ms ease, opacity 160ms ease;
}

.file-row.dragging {
  opacity: 0.45;
}

.file-row.drag-target {
  border-color: var(--primary);
}

.drag-handle {
  padding: 6px;
  border: 0;
  background: transparent;
  color: var(--muted);
  cursor: grab;
}

.file-number {
  width: 30px;
  height: 30px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: var(--surface);
  color: var(--primary);
  font-size: 13px;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.file-details {
  min-width: 0;
}

.file-name {
  overflow: hidden;
  margin-bottom: 2px;
  font-size: 14px;
  font-weight: 700;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-info {
  color: var(--muted);
  font-size: 12px;
}

.remove-button {
  width: 38px;
  height: 38px;
  padding: 0;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 9px;
  background: transparent;
  color: var(--danger);
  cursor: pointer;
}

.row-actions {
  display: flex;
  align-items: center;
  gap: 2px;
}

.move-button {
  width: 34px;
  height: 38px;
  padding: 0;
  display: grid;
  place-items: center;
  border: 1px solid transparent;
  border-radius: 9px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
}

.move-button:hover:not(:disabled) {
  border-color: var(--border);
  background: var(--surface);
  color: var(--primary);
}

.move-button:disabled {
  opacity: 0.28;
  cursor: not-allowed;
}

.remove-button:hover {
  border-color: color-mix(in srgb, var(--danger) 35%, transparent);
  background: var(--danger-soft);
}

.toolbar {
  padding-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.button {
  min-height: 44px;
  padding: 10px 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid transparent;
  border-radius: 9px;
  font-weight: 750;
  cursor: pointer;
  transition: transform 150ms ease, background 150ms ease, border-color 150ms ease;
}

.button:active {
  transform: scale(0.98);
}

.button-primary {
  margin-left: auto;
  background: var(--primary);
  color: #fff;
}

.button-primary:hover {
  background: var(--primary-hover);
}

.button-secondary {
  border-color: var(--border);
  background: transparent;
  color: var(--text);
}

.button-secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.button:disabled {
  opacity: 0.55;
  cursor: wait;
}

.status {
  margin: 14px 0 0;
  padding: 11px 13px;
  border-radius: 9px;
  background: var(--surface-soft);
  color: var(--muted);
  font-size: 13px;
}

.status.success {
  background: var(--success-soft);
  color: var(--success);
}

.status.error {
  background: var(--danger-soft);
  color: var(--danger);
}

.hidden {
  display: none !important;
}

.content-section {
  margin-top: 72px;
}

.section-label {
  margin-bottom: 8px;
  color: var(--primary);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.content-section > h2 {
  max-width: 680px;
  margin-bottom: 26px;
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.025em;
  text-wrap: balance;
}

.steps {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr 1.05fr;
  gap: 16px;
}

.step {
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: var(--surface);
}

.step:nth-child(2) {
  margin-top: 24px;
}

.step-number {
  display: block;
  margin-bottom: 28px;
  color: var(--primary);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.step h3 {
  margin-bottom: 7px;
  font-size: 17px;
}

.step p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 14px;
}

.faq-list {
  display: grid;
  gap: 10px;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface);
}

.faq-item summary {
  padding: 16px 18px;
  font-weight: 750;
  cursor: pointer;
}

.faq-item p {
  margin: 0;
  padding: 0 18px 18px;
  color: var(--muted);
  font-size: 14px;
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 16px;
  color: var(--muted);
  text-align: center;
  font-size: 13px;
}

.site-footer nav {
  margin-bottom: 6px;
}

.site-footer a {
  margin-inline: 7px;
  text-decoration: none;
}

.site-footer a:hover {
  color: var(--primary);
}

@media (max-width: 760px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 22px;
  }

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

  .step:nth-child(2) {
    margin-top: 0;
  }

  .button-primary {
    width: 100%;
    margin-left: 0;
    order: 3;
  }
}

@media (max-width: 520px) {
  .header-inner,
  .container {
    width: min(100% - 22px, 1040px);
  }

  .brand span {
    display: none;
  }

  .container {
    padding-top: 18px;
  }

  .file-row {
    grid-template-columns: auto minmax(0, 1fr) auto;
  }

  .output-name {
    grid-template-columns: 1fr;
    gap: 7px;
  }

  .file-number {
    display: none;
  }

  .toolbar .button-secondary {
    flex: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}