:root {
  --color-surface: #ffffff;
  --color-border: #e4e6ec;
  --color-text: #1f2430;
  --color-text-sub: #6b7280;

  --color-assistant: #6c5ce7;
  --color-assistant-bg: #f2effe;
  --color-assistant-dark: #5a3fe0;

  --color-generate: #00b894;
  --color-generate-bg: #e9fbf5;
  --color-generate-dark: #00a381;

  --color-error: #e63946;
  --color-error-bg: #fdecee;

  --radius-lg: 16px;
  --radius-md: 10px;
  --shadow-card: 0 4px 16px rgba(20, 20, 40, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "BIZ UDPGothic", "BIZ UDGothic", "UD デジタル 教科書体 N-R",
    "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", "Segoe UI",
    sans-serif;
  font-size: 17px;
  background: linear-gradient(160deg, #dde0ea 0%, #d5d9e5 100%);
  background-attachment: fixed;
  color: var(--color-text);
  line-height: 1.7;
}

/* Header */
.app-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 20px 0;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-mark {
  font-size: 28px;
}

.app-header h1 {
  font-size: 25px;
  font-weight: 700;
  margin: 0;
  letter-spacing: 0.3px;
}

/* API key banner */
.api-banner {
  max-width: 1200px;
  margin: 16px auto 0;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  background: var(--color-error-bg);
  color: var(--color-error);
  font-size: 15px;
  font-weight: 600;
}

.api-banner code {
  background: rgba(230, 57, 70, 0.12);
  padding: 1px 6px;
  border-radius: 4px;
}

/* Layout */
.main-layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 40px 24px 64px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  align-items: start;
}

@media (max-width: 900px) {
  .main-layout {
    grid-template-columns: 1fr;
    gap: 40px;
    padding: 24px 16px 48px;
  }
}

/* Panel */
.panel {
  position: relative;
  border-radius: var(--radius-lg);
  padding: 24px;
  background: transparent;
}

.panel-assistant {
  background: linear-gradient(180deg, var(--color-assistant-bg), transparent 140px);
  border: 1px solid #e4dcfc;
}

.panel-generate {
  background: linear-gradient(180deg, var(--color-generate-bg), transparent 140px);
  border: 1px solid #cdf3e6;
}

.panel-badge {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  padding: 4px 10px;
  border-radius: 999px;
  color: #fff;
  margin-bottom: 10px;
}

.badge-assistant {
  background: var(--color-assistant);
}

.badge-generate {
  background: var(--color-generate);
}

.panel-title {
  font-size: 23px;
  font-weight: 700;
  margin: 0 0 8px;
}

.panel-desc {
  color: var(--color-text-sub);
  font-size: 16px;
  margin: 0 0 20px;
}

/* Card */
.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-card);
}

/* Fields */
.field {
  margin-bottom: 22px;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 520px) {
  .field-row {
    grid-template-columns: 1fr;
  }
}

.field-label {
  display: block;
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--color-text);
}

.input-control {
  width: 100%;
  padding: 11px 13px;
  font-size: 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #fafbfc;
  color: var(--color-text);
  font-family: inherit;
  transition: border-color 0.15s, background 0.15s;
}

.input-control:focus {
  outline: none;
  border-color: var(--color-assistant);
  background: #fff;
}

.panel-generate .input-control:focus {
  border-color: var(--color-generate);
}

.textarea {
  resize: vertical;
  min-height: 90px;
}

/* Upload box */
.upload-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  text-align: center;
  padding: 28px 16px;
  border: 2px dashed #d7d2f5;
  border-radius: var(--radius-md);
  background: #faf9ff;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.upload-box:hover {
  border-color: var(--color-assistant);
  background: #f5f2ff;
}

.upload-icon {
  font-size: 26px;
}

.upload-text {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
}

.upload-sub {
  font-size: 13px;
  color: var(--color-text-sub);
}

.upload-filename {
  margin-top: 8px;
  font-size: 14px;
  color: var(--color-assistant-dark);
  font-weight: 600;
}

/* Buttons */
.btn {
  display: block;
  width: 100%;
  padding: 14px 20px;
  font-size: 17px;
  font-weight: 700;
  border: none;
  border-radius: var(--radius-md);
  color: #fff;
  cursor: pointer;
  transition: transform 0.1s, filter 0.15s;
}

.btn:hover {
  filter: brightness(1.05);
}

.btn:active {
  transform: translateY(1px);
}

.btn-assistant {
  background: var(--color-assistant);
}

.btn-generate {
  background: var(--color-generate);
}

/* Result box (assistant) */
.result-box {
  margin-top: 22px;
  padding: 18px 20px;
  border-radius: var(--radius-md);
  background: var(--color-assistant-bg);
}

.result-label {
  font-size: 14px;
  font-weight: 700;
  color: var(--color-text-sub);
  margin-bottom: 8px;
  letter-spacing: 0.5px;
}

.result-text {
  font-size: 15.5px;
  margin: 0;
  color: var(--color-text);
  white-space: pre-wrap;
}

.result-error {
  color: var(--color-error) !important;
  font-weight: 600;
}

/* Preview area (generate) */
.preview-area {
  margin-top: 22px;
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
}

@media (max-width: 600px) {
  .preview-grid {
    grid-template-columns: 1fr;
  }
}

.preview-card {
  border-radius: var(--radius-md);
  background: var(--color-generate-bg);
  padding: 16px;
  text-align: center;
}

.preview-thumb {
  width: 100%;
  aspect-ratio: 3 / 4;
  border-radius: 8px;
  background: linear-gradient(160deg, #d7f5ea, #c7f0e0);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 30px;
  margin-bottom: 10px;
  color: var(--color-generate-dark);
}

.preview-page-label {
  font-weight: 700;
  font-size: 16px;
  margin-bottom: 2px;
}

.preview-panel-count {
  font-size: 14px;
  color: var(--color-text-sub);
  margin-bottom: 6px;
}

.preview-caption {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-generate-dark);
  margin-bottom: 2px;
}

.preview-note {
  font-size: 13px;
  color: var(--color-text-sub);
}

.preview-empty {
  grid-column: 1 / -1;
  text-align: center;
  font-size: 15px;
  color: var(--color-text-sub);
  padding: 24px 12px;
}

.preview-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 8px;
}

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

/* Download buttons */
.btn-download {
  display: inline-block;
  margin-top: 14px;
  padding: 12px 22px;
  font-size: 16px;
  font-weight: 700;
  font-family: inherit;
  border: none;
  border-radius: var(--radius-md);
  color: #fff;
  cursor: pointer;
  transition: transform 0.1s, filter 0.15s;
}

.btn-download:hover {
  filter: brightness(1.05);
}

.btn-download:active {
  transform: translateY(1px);
}

.panel-assistant .btn-download {
  background: var(--color-assistant-dark);
}

.panel-generate .btn-download {
  background: var(--color-generate-dark);
}

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

@media (max-width: 480px) {
  .panel {
    padding: 18px;
  }

  .card {
    padding: 20px;
  }
}

/* Footer */
.app-footer {
  text-align: center;
  padding: 20px;
  font-size: 14px;
  color: var(--color-text-sub);
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
}