* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', sans-serif;
  background: #f5f5f5;
  color: #333;
  line-height: 1.7;
}

header {
  background: #fff;
  border-bottom: 1px solid #e0e0e0;
  padding: 1rem 0;
}

.header-inner {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.logo {
  font-size: 1.2rem;
  font-weight: bold;
  color: #1a73e8;
  text-decoration: none;
}

main {
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

h1 {
  font-size: 1.8rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
}

h2 {
  font-size: 1.2rem;
  font-weight: bold;
  margin-bottom: 1rem;
}

.description {
  color: #666;
  margin-bottom: 1.5rem;
}

.card {
  background: #fff;
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  border: 1px solid #e0e0e0;
}

.drop-area {
  border: 2px dashed #1a73e8;
  border-radius: 12px;
  padding: 3rem 1.5rem;
  text-align: center;
  cursor: pointer;
  transition: background 0.2s;
}

.drop-area.dragover {
  background: #f0f4ff;
}

.drop-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.drop-area p {
  color: #666;
  margin-bottom: 0.5rem;
}

.drop-sub {
  font-size: 0.875rem;
}

.drop-note {
  font-size: 0.8rem;
  color: #999;
  margin-top: 0.5rem;
}

.btn {
  display: inline-block;
  padding: 0.7rem 2rem;
  background: #1a73e8;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
  text-decoration: none;
  margin: 0.5rem 0;
}

.btn:hover {
  background: #1557b0;
}

.input-group {
  margin-bottom: 1.2rem;
}

.input-group label {
  display: block;
  font-size: 0.875rem;
  color: #666;
  margin-bottom: 0.4rem;
}

.input-group input[type=number] {
  width: 100%;
  padding: 0.6rem 0.8rem;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  font-size: 1rem;
  color: #333;
}

.range-row {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.range-row input[type=range] {
  flex: 1;
  accent-color: #1a73e8;
}

.range-row span {
  font-size: 0.95rem;
  font-weight: bold;
  min-width: 60px;
  text-align: right;
}

.radio-group {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.95rem;
  cursor: pointer;
}

.btn-process {
  display: inline-block;
  padding: 0.8rem 2.5rem;
  background: #1a73e8;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
  margin-top: 0.5rem;
}

.btn-process:hover {
  background: #1557b0;
}

.btn-download {
  display: inline-block;
  padding: 0.8rem 2.5rem;
  background: #4CAF50;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
  margin-top: 1rem;
}

.btn-download:hover {
  background: #388E3C;
}

.image-info {
  font-size: 0.875rem;
  color: #666;
  margin-bottom: 1rem;
  padding: 0.8rem;
  background: #f5f5f5;
  border-radius: 8px;
}

.preview-img {
  max-width: 100%;
  border-radius: 8px;
  border: 1px solid #e0e0e0;
}

footer {
  text-align: center;
  padding: 2rem;
  color: #999;
  font-size: 0.875rem;
}

footer a {
  color: #999;
  text-decoration: none;
  margin: 0 0.5rem;
}

footer a:hover {
  color: #1a73e8;
}

footer p {
  margin-bottom: 0.3rem;
}

@media (max-width: 600px) {
  h1 {
    font-size: 1.4rem;
  }

  .radio-group {
    gap: 1rem;
  }
}