:root {
  --color-bg: #f4f5f9;
  --color-surface: #ffffff;
  --color-border: #e4e6ef;
  --color-text: #23243a;
  --color-text-muted: #6b6d84;

  --color-assistant: #6c5ce7;
  --color-assistant-bg: #f2effd;
  --color-assistant-dark: #5641d8;

  --color-generate: #ff6b8a;
  --color-generate-bg: #fff0f3;
  --color-generate-dark: #e84f70;

  --radius-lg: 18px;
  --radius-md: 12px;
  --shadow-card: 0 6px 24px rgba(35, 36, 58, 0.08);
}

* {
  box-sizing: border-box;
}

/* hidden属性は、display を個別指定したクラス（.loading-box など）より
   常に優先されるようにする（詳細度が同じだと属性側が負けるため） */
[hidden] {
  display: none !important;
}

body {
  margin: 0;
  font-family: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic UI", "Yu Gothic", "Meiryo",
    -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
}

/* ---------- Header ---------- */
.app-header {
  background: linear-gradient(90deg, var(--color-assistant) 0%, var(--color-generate) 100%);
  padding: 28px 24px;
}

.app-header__inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
}

@media (max-width: 480px) {
  .app-header {
    padding: 20px 16px;
  }
}

.app-header__icon {
  font-size: 2.4rem;
}

.app-header__title {
  margin: 0;
  color: #fff;
  font-size: 1.6rem;
  letter-spacing: 0.02em;
}

.app-header__subtitle {
  margin: 4px 0 0;
  color: rgba(255, 255, 255, 0.9);
  font-size: 0.9rem;
}

/* ---------- Layout ---------- */
.layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 32px 24px 64px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  align-items: start;
}

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

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

@media (max-width: 480px) {
  .panel {
    padding: 20px;
  }
}

.panel--assistant {
  border-top: 5px solid var(--color-assistant);
}

.panel--generate {
  border-top: 5px solid var(--color-generate);
}

.panel__badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 999px;
  margin-bottom: 14px;
}

.panel--assistant .panel__badge {
  background: var(--color-assistant-bg);
  color: var(--color-assistant-dark);
}

.panel--generate .panel__badge {
  background: var(--color-generate-bg);
  color: var(--color-generate-dark);
}

.panel__title {
  margin: 0 0 8px;
  font-size: 1.25rem;
}

.panel__desc {
  margin: 0 0 24px;
  color: var(--color-text-muted);
  font-size: 0.92rem;
}

/* ---------- Fields ---------- */
.field {
  margin-bottom: 20px;
}

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

@media (max-width: 480px) {
  .field-row {
    grid-template-columns: 1fr;
  }
}

.field__label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 8px;
}

.select,
.textarea {
  width: 100%;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  font-size: 0.92rem;
  font-family: inherit;
  color: var(--color-text);
  background: #fbfbfd;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.select:focus,
.textarea:focus {
  outline: none;
  border-color: var(--color-assistant);
  box-shadow: 0 0 0 3px rgba(108, 92, 231, 0.12);
}

.panel--generate .select:focus,
.panel--generate .textarea:focus {
  border-color: var(--color-generate);
  box-shadow: 0 0 0 3px rgba(255, 107, 138, 0.14);
}

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

/* ---------- Upload box ---------- */
.upload-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px 16px;
  cursor: pointer;
  text-align: center;
  background: #fbfbfd;
  transition: border-color 0.15s ease, background 0.15s ease;
}

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

.upload-box__icon {
  font-size: 1.8rem;
}

.upload-box__text {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--color-text);
}

.upload-box__hint {
  font-size: 0.78rem;
  color: var(--color-text-muted);
}

/* ---------- Buttons ---------- */
.btn {
  display: block;
  width: 100%;
  border: none;
  border-radius: var(--radius-md);
  padding: 14px 20px;
  font-size: 1rem;
  font-weight: 700;
  color: #fff;
  cursor: pointer;
  transition: transform 0.1s ease, box-shadow 0.15s ease, opacity 0.15s ease;
}

.btn:hover {
  transform: translateY(-1px);
  opacity: 0.94;
}

.btn:active {
  transform: translateY(0);
}

.btn--assistant {
  background: linear-gradient(90deg, var(--color-assistant), var(--color-assistant-dark));
  box-shadow: 0 6px 16px rgba(108, 92, 231, 0.28);
}

.btn--generate {
  background: linear-gradient(90deg, var(--color-generate), var(--color-generate-dark));
  box-shadow: 0 6px 16px rgba(255, 107, 138, 0.3);
}

/* ---------- Loading / Error ---------- */
.loading-box {
  margin-top: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.88rem;
  color: var(--color-text-muted);
}

.loading-spinner {
  width: 16px;
  height: 16px;
  border: 2px solid var(--color-border);
  border-top-color: var(--color-assistant);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  flex-shrink: 0;
}

.panel--generate .loading-spinner {
  border-top-color: var(--color-generate);
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.error-box {
  margin-top: 16px;
  background: #fff4f2;
  border: 1px solid #f3b8ab;
  color: #b3401f;
  border-radius: var(--radius-md);
  padding: 12px 16px;
  font-size: 0.86rem;
}

/* ---------- Result box (assistant) ---------- */
.result-box {
  margin-top: 20px;
  background: var(--color-assistant-bg);
  border: 1px solid rgba(108, 92, 231, 0.2);
  border-radius: var(--radius-md);
  padding: 18px 20px;
  opacity: 0;
  transform: translateY(6px);
  animation: fade-in 0.35s ease forwards;
}

.result-box__label {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--color-assistant-dark);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 8px;
}

.result-box__text {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text);
}

@keyframes fade-in {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- Preview grid (generate) ---------- */
.preview-heading {
  margin-top: 8px;
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 16px;
}

/* タブレット幅ではおよそ2列になるように固定する */
@media (max-width: 900px) {
  .preview-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* スマホ幅では1列に */
@media (max-width: 560px) {
  .preview-grid {
    grid-template-columns: 1fr;
  }
}

.preview-card {
  background: #fbfbfd;
  border-radius: var(--radius-md);
  box-shadow: 0 2px 10px rgba(35, 36, 58, 0.05);
  padding: 14px;
  opacity: 0;
  transform: translateY(6px);
  animation: fade-in 0.35s ease forwards;
}

.preview-card__page {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--color-generate-dark);
}

.preview-card__panels {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  margin-bottom: 10px;
}

.preview-card__thumb {
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  aspect-ratio: 3 / 4;
  background: repeating-linear-gradient(
    45deg,
    #f4f5f9,
    #f4f5f9 10px,
    #eceef7 10px,
    #eceef7 20px
  );
  border: 1px dashed var(--color-border);
  border-radius: 8px;
  text-align: center;
  padding: 10px;
}

.preview-card__thumb-icon {
  font-size: 1.6rem;
  opacity: 0.6;
}

.preview-card__thumb-label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--color-text-muted);
}

.preview-card__thumb-note {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  padding: 0 4px;
}

.preview-card__image {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ---------- Footer ---------- */
.app-footer {
  text-align: center;
  padding: 20px;
  color: var(--color-text-muted);
  font-size: 0.78rem;
}