:root {
  --color-bg: #eef9fb;
  --color-accent: #14b8a6;
  --color-accent-dark: #0d9488;
  --color-accent-soft: #ccfbf1;
  --color-surface: #ffffff;
  --color-border: #a7e8df;
  --color-text: #1d1d1f;
  --color-text-secondary: #5b6b6a;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Malgun Gothic", sans-serif;
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px 16px 64px;
}

h1 {
  font-size: 28px;
  margin-bottom: 4px;
  padding-bottom: 8px;
  border-bottom: 3px solid var(--color-accent);
  display: inline-block;
}

.subtitle {
  color: var(--color-text-secondary);
  margin-top: 12px;
  margin-bottom: 24px;
}

.upload-area, .controls, .preview-area {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(20, 184, 166, 0.12);
}

.upload-area {
  position: relative;
  border: 2px dashed var(--color-border);
  border-radius: 16px;
  min-height: 96px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 16px 24px;
  cursor: pointer;
  transition: border-color 0.15s, background-color 0.15s;
}

.upload-area.drag-over {
  border-color: var(--color-accent);
  background-color: var(--color-accent-soft);
}

.upload-icon {
  width: 28px;
  height: 28px;
  margin-bottom: 8px;
  color: var(--color-accent);
}

.upload-btn {
  border-radius: 999px;
  padding: 14px 36px;
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 14px;
}

.upload-hint {
  color: var(--color-text-secondary);
  font-size: 15px;
  margin: 0;
}

.upload-formats {
  color: var(--color-text-secondary);
  font-size: 12px;
  margin: 10px 0 0;
}

.offline-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--color-text-secondary);
  margin-top: 8px;
}

.offline-badge-icon {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  color: currentColor;
}

.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;
}

.compress-warning {
  color: var(--color-warning-text, #9a6700);
  background: var(--color-warning-bg, #fff8e5);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 13px;
  margin: 8px 0;
}

.error-message {
  color: var(--color-error-text, #d70015);
  margin-top: 12px;
}

.controls label {
  display: block;
  margin-bottom: 8px;
}

.controls input[type="range"] {
  width: 100%;
  margin-bottom: 16px;
}

button, #downloadBtn, .btn {
  background: var(--color-accent);
  color: var(--color-on-accent, #fff);
  border: none;
  border-radius: 8px;
  padding: 10px 20px;
  font-size: 15px;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
}

button:hover, #downloadBtn:hover, .btn:hover {
  background: var(--color-accent-dark);
}

.preview-area {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.preview-box {
  flex: 1;
  min-width: 240px;
}

.preview-box img {
  max-width: 100%;
  border-radius: 8px;
  display: block;
  margin-bottom: 8px;
}

@media (max-width: 600px) {
  .preview-area {
    flex-direction: column;
  }
}

.resize-fields {
  display: flex;
  align-items: flex-end;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.controls .resize-label {
  display: flex;
  flex-direction: column;
  font-size: 13px;
  color: var(--color-text-secondary);
  gap: 4px;
}

.resize-label input[type="number"] {
  width: 90px;
  padding: 8px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 14px;
}

.controls .checkbox-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--color-text);
  margin-bottom: 8px;
}

.upscale-mode-label {
  font-weight: 600;
  margin: 0 0 10px;
}

.upscale-mode-group {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 16px;
}

.controls .radio-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--color-text);
}

.radio-label input[disabled] {
  cursor: not-allowed;
}

.upscale-mode-note {
  color: var(--color-text-secondary);
  font-size: 12px;
}

#formatSelect {
  display: block;
  width: 100%;
  max-width: 200px;
  padding: 8px;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  font-size: 14px;
  margin-bottom: 16px;
}

.tool-nav {
  margin: 0 0 20px;
}

.tool-nav a {
  color: var(--color-accent);
  text-decoration: none;
  font-size: 14px;
}

.pdf-section {
  margin-bottom: 32px;
}

.pdf-section h2 {
  font-size: 20px;
  margin-bottom: 12px;
}

.file-list {
  list-style: none;
  padding: 0;
  margin: 12px 0;
  background: var(--color-surface);
  border-radius: 12px;
  box-shadow: 0 1px 3px rgba(20, 184, 166, 0.12);
}

.file-list:empty {
  display: none;
}

.file-list li {
  padding: 10px 16px;
  border-bottom: 1px solid var(--color-border);
  font-size: 14px;
  display: flex;
  justify-content: space-between;
}

.file-list li:last-child {
  border-bottom: none;
}

.pdf-progress {
  color: var(--color-text-secondary);
  font-size: 14px;
  margin: 12px 0;
}

.pdf-page-list {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.pdf-page-item {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 12px;
  box-shadow: 0 1px 3px rgba(20, 184, 166, 0.12);
  width: 160px;
  text-align: center;
}

.pdf-page-item img {
  max-width: 100%;
  border-radius: 8px;
  display: block;
  margin-bottom: 8px;
  border: 1px solid var(--color-border);
}

.pdf-page-item a {
  font-size: 13px;
  padding: 6px 12px;
}

.info-section {
  background: var(--color-surface);
  border-radius: 12px;
  padding: 20px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(20, 184, 166, 0.12);
}

.info-section h2 {
  font-size: 18px;
  margin-top: 0;
}

.info-section details {
  border-top: 1px solid var(--color-border);
  padding: 12px 0;
}

.info-section details:first-of-type {
  border-top: none;
}

.info-section details[open] {
  background: var(--color-accent-soft);
}

.info-section summary {
  cursor: pointer;
  font-weight: 600;
}

.info-section summary + p {
  color: var(--color-text-secondary);
  margin: 10px 0 0;
}

.guide-image {
  margin: 20px 0;
  text-align: center;
}

.guide-image img,
.guide-image svg {
  max-width: 100%;
  border-radius: 8px;
  border: 1px solid var(--color-border);
  display: block;
  margin: 0 auto;
  background: var(--color-surface);
}

.guide-image figcaption {
  font-size: 13px;
  color: var(--color-text-secondary);
  margin-top: 8px;
}

.site-footer {
  text-align: center;
  padding: 24px 0;
  font-size: 13px;
}

.site-footer a {
  color: var(--color-text-secondary);
  text-decoration: none;
  margin: 0 10px;
}

.site-footer a:hover {
  text-decoration: underline;
  color: var(--color-accent);
}