:root {
  --page-bg: #fafafa;
  --page-bg-accent: #f3f4f6;
  --surface: #ffffff;
  --surface-subtle: #f5f6f8;
  --foreground: #212121;
  --muted: #616161;
  --border: #e0e0e0;
  --link: #1565c0;
  --primary-text-on-link: #ffffff;
  --shadow: rgba(0, 0, 0, 0.07);
}

body[data-theme="dark"] {
  --page-bg: #212121;
  --page-bg-accent: #1e1e1e;
  --surface: #2a2a2a;
  --surface-subtle: #343434;
  --foreground: #dadada;
  --muted: #b2b2b2;
  --border: #424242;
  --link: #42a5f5;
  --primary-text-on-link: #0f1318;
  --shadow: rgba(0, 0, 0, 0.18);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Avenir Next", "Helvetica Neue", "Segoe UI", sans-serif;
  color: var(--foreground);
  background: linear-gradient(to bottom, var(--page-bg), var(--page-bg-accent));
  min-height: 100vh;
  line-height: 1.45;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.site-header {
  background: var(--page-bg);
  border-bottom: 1px solid var(--border);
}

.site-nav {
  max-width: 1700px;
  margin: 0 auto;
  padding: 12px 20px;
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

.home-link {
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--foreground);
  white-space: nowrap;
}

.nav-links {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

.nav-links a {
  font-weight: 700;
  color: var(--foreground);
}

.nav-links a.is-current {
  color: var(--link);
}

.theme-toggle {
  border: 1px solid var(--border);
  background: var(--surface-subtle);
  color: var(--foreground);
  border-radius: 999px;
  padding: 6px 12px;
  font-weight: 600;
  cursor: pointer;
}

.page {
  max-width: 1300px;
  margin: 0 auto;
  padding: 20px 24px 28px;
}

.hero {
  margin-bottom: 18px;
}

.hero h1 {
  margin: 0 0 8px;
  font-size: clamp(1.5rem, 2vw, 2rem);
}

.hero p {
  margin: 0 0 10px;
  color: var(--muted);
}

.hero-points {
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
}

.app-grid {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 24px;
}

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: 0 2px 8px var(--shadow);
}

.controls-panel {
  padding: 20px;
  overflow: auto;
}

.controls-panel h2 {
  margin: 0 0 8px;
  font-size: 1.5rem;
}

.controls-panel > p {
  margin: 0 0 6px;
}

.drop-zone {
  margin-top: 16px;
  padding: 18px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--surface-subtle);
  min-height: 170px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  transition: border-color 160ms ease, background-color 160ms ease;
}

.drop-zone.is-hovering {
  border-color: var(--link);
  background: rgba(21, 101, 192, 0.1);
}

.drop-zone.is-disabled {
  opacity: 0.8;
}

.drop-zone p {
  margin: 0;
}

#dropZoneTitle {
  font-size: 1.05rem;
  font-weight: 600;
}

#dropZoneFileName {
  margin-top: 6px;
  color: var(--muted);
  font-size: 0.92rem;
}

.control-row {
  margin-top: 12px;
  display: flex;
  justify-content: center;
}

.control-section {
  margin-top: 14px;
}

.control-section h3 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.chip-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 7px 12px;
  background: var(--surface-subtle);
  color: var(--foreground);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.chip.is-selected {
  border-color: var(--link);
  box-shadow: inset 0 0 0 1px var(--link);
}

.chip-swatch {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 1px solid rgba(0, 0, 0, 0.12);
}

.muted {
  color: var(--muted);
  font-size: 0.92rem;
}

input[type="range"] {
  margin: 8px 0 12px;
  width: 100%;
  height: 22px;
  background: transparent;
  -webkit-appearance: none;
  appearance: none;
  --range-track: linear-gradient(to right, #d7dce4, #b9c3d2);
}

input[type="range"]:focus {
  outline: none;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--range-track);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  margin-top: -5px;
  border: 2px solid var(--link);
  background: var(--surface);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

input[type="range"]::-moz-range-track {
  height: 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--range-track);
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid var(--link);
  background: var(--surface);
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

input[type="range"]::-moz-focus-outer {
  border: 0;
}

.history-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.history-header h3 {
  margin: 0;
}

.history-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.history-item {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface-subtle);
  padding: 10px;
}

.history-item strong {
  display: block;
  font-size: 0.95rem;
}

.history-item small {
  color: var(--muted);
  display: block;
}

.preview-panel {
  padding: 20px 24px 28px;
  display: flex;
  flex-direction: column;
}

.preview-canvas-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 0;
}

#previewCanvas {
  display: block;
  width: auto;
  height: auto;
  max-width: 100%;
  max-height: 100%;
  border-radius: 8px;
}

.preview-footer {
  margin-top: 12px;
  display: flex;
  align-items: center;
  gap: 12px;
}

#previewTitle {
  margin: 0;
  font-weight: 600;
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
}

.btn {
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 9px 14px;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--link);
  color: var(--primary-text-on-link);
}

.btn-outline {
  background: transparent;
  color: var(--foreground);
  border-color: var(--border);
}

.btn-text {
  background: transparent;
  color: var(--link);
  padding: 0;
  border: 0;
}

.seo-copy {
  margin-top: 24px;
}

.seo-copy h2 {
  margin: 20px 0 8px;
  font-size: 1.3rem;
}

.seo-copy h3 {
  margin: 14px 0 4px;
  font-size: 1rem;
}

.seo-copy p {
  margin: 0;
  color: var(--muted);
}

.noscript-msg {
  max-width: 1300px;
  margin: 0 auto 20px;
  padding: 12px 24px;
  color: #9c2714;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 939px) {
  .app-grid {
    grid-template-columns: 1fr;
  }

  .controls-panel {
    order: 1;
  }

  .preview-panel {
    order: 2;
  }
}

@media (max-width: 599px) {
  .site-nav {
    padding: 10px 12px;
  }

  .page {
    padding: 12px;
  }

  .controls-panel {
    padding: 14px;
  }

  .preview-panel {
    padding: 14px;
  }

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