:root {
  --font-base: 'Inter', 'Zen Kaku Gothic New', "Hiragino Kaku Gothic ProN", "Segoe UI", -apple-system, BlinkMacSystemFont, sans-serif;

  --color-bg: #f3f4fb;
  --color-bg-accent: #eef1fb;
  --color-surface: #ffffff;
  --color-border: #e6e8f2;
  --color-text: #1c2033;
  --color-text-muted: #6b7086;

  --color-assistant: #6c5ce7;
  --color-assistant-bg: #f2effd;
  --color-assistant-dark: #5b4bd1;

  --color-generate: #00b894;
  --color-generate-bg: #e9fbf5;
  --color-generate-dark: #00a382;

  --radius-lg: 20px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --shadow-card: 0 4px 16px rgba(31, 35, 60, 0.06);
  --shadow-card-hover: 0 10px 28px rgba(31, 35, 60, 0.10);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font-base);
  background:
    radial-gradient(1000px 480px at 15% -10%, var(--color-bg-accent), transparent),
    radial-gradient(900px 460px at 100% 0%, #eafaf3, transparent),
    var(--color-bg);
  color: var(--color-text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.app-header {
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
  padding: 18px 24px;
  position: sticky;
  top: 0;
  z-index: 10;
}
.app-header__inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 12px;
}
.app-header__logo {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  font-size: 20px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-assistant-bg), var(--color-generate-bg));
}
.app-header__title {
  font-size: 20px;
  font-weight: 800;
  margin: 0;
  letter-spacing: 0.2px;
}

.app-main {
  max-width: 1160px;
  margin: 0 auto;
  padding: 40px 24px 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}

@media (max-width: 900px) {
  .app-main {
    grid-template-columns: 1fr;
    padding: 24px 16px 16px;
    gap: 20px;
  }
  .app-header { padding: 14px 16px; }
}

.panel {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  border: 1px solid var(--color-border);
  padding: 32px;
  position: relative;
}

.panel__badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 14px;
}
.panel--assistant .panel__badge {
  background: var(--color-assistant-bg);
  color: var(--color-assistant);
}
.panel--generate .panel__badge {
  background: var(--color-generate-bg);
  color: var(--color-generate-dark);
}

.panel--assistant { border-top: 3px solid var(--color-assistant); }
.panel--generate { border-top: 3px solid var(--color-generate); }

.panel__title {
  font-size: 20px;
  font-weight: 800;
  margin: 0 0 10px;
  letter-spacing: 0.1px;
}
.panel__desc {
  font-size: 14px;
  color: var(--color-text-muted);
  margin: 0 0 28px;
}

.field { margin-bottom: 20px; }
.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: 13px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 7px;
}

.select, .textarea {
  width: 100%;
  padding: 12px 14px;
  font-size: 16px;
  font-family: inherit;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-surface);
  color: var(--color-text);
  resize: vertical;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}
.select {
  appearance: none;
  -webkit-appearance: none;
  padding-right: 40px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='20' viewBox='0 0 20 20'%3E%3Cpath d='M5.5 7.5L10 12l4.5-4.5' fill='none' stroke='%236b7086' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  cursor: pointer;
}
.select:focus, .textarea:focus {
  outline: none;
  border-color: var(--color-assistant);
  box-shadow: 0 0 0 3px rgba(108, 92, 231, 0.15);
}
.panel--generate .select:focus, .panel--generate .textarea:focus {
  border-color: var(--color-generate);
  box-shadow: 0 0 0 3px rgba(0, 184, 148, 0.15);
}

.upload-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 30px 16px;
  border: 2px dashed #d7d2f8;
  border-radius: var(--radius-md);
  background: var(--color-assistant-bg);
  cursor: pointer;
  text-align: center;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.upload-box:hover {
  border-color: var(--color-assistant);
}
.upload-box__icon { font-size: 26px; }
.upload-box__text {
  font-size: 13px;
  color: var(--color-text-muted);
}
.upload-box__filename {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-assistant-dark);
}

.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 50px;
  padding: 13px 20px;
  font-size: 15px;
  font-weight: 700;
  font-family: inherit;
  color: #fff;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.15s ease, opacity 0.15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn--assistant {
  background: linear-gradient(135deg, var(--color-assistant), var(--color-assistant-dark));
  box-shadow: 0 6px 16px rgba(108, 92, 231, 0.32);
}
.btn--assistant:hover { box-shadow: 0 10px 22px rgba(108, 92, 231, 0.38); }

.btn--generate {
  background: linear-gradient(135deg, var(--color-generate), var(--color-generate-dark));
  box-shadow: 0 6px 16px rgba(0, 184, 148, 0.32);
}
.btn--generate:hover { box-shadow: 0 10px 22px rgba(0, 184, 148, 0.38); }

.status-box {
  display: none;
  margin-top: 14px;
  padding: 12px 14px;
  border-radius: var(--radius-md);
  font-size: 13px;
  line-height: 1.6;
}
.status-box.is-visible { display: block; }
.status-box--error {
  background: #fdecea;
  border: 1px solid #f5c2c0;
  color: #c0392b;
}
.status-box--info {
  background: #eaf3fd;
  border: 1px solid #bcdcf7;
  color: #1c6bb0;
}

.field__note {
  margin: 8px 0 0;
  font-size: 12px;
  color: var(--color-text-muted);
}

.result-box {
  margin-top: 20px;
  padding: 20px;
  background: var(--color-assistant-bg);
  border: 1px solid #ddd6fb;
  border-radius: var(--radius-md);
  display: none;
}
.result-box.is-visible { display: block; }
.result-box__label {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-assistant-dark);
  margin-bottom: 10px;
  letter-spacing: 0.5px;
}
.result-box__text {
  font-size: 14px;
  margin: 0;
  color: var(--color-text);
  white-space: pre-wrap;
}

.preview-grid {
  margin-top: 20px;
  display: none;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
}
.preview-grid.is-visible { display: grid; }

@media (max-width: 900px) and (min-width: 601px) {
  .preview-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .preview-grid { grid-template-columns: 1fr; }
}

.preview-card {
  background: var(--color-generate-bg);
  border: 1px solid #bdf0dd;
  border-radius: var(--radius-md);
  padding: 14px;
  text-align: center;
  transition: box-shadow 0.15s ease, transform 0.15s ease;
}
.preview-card:hover {
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-2px);
}
.preview-card__thumb {
  aspect-ratio: 3 / 4;
  background: repeating-linear-gradient(
    45deg,
    #ffffff,
    #ffffff 10px,
    #dff7ee 10px,
    #dff7ee 20px
  );
  border-radius: var(--radius-sm);
  border: 1px solid #bdf0dd;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  margin-bottom: 10px;
  color: var(--color-generate-dark);
  overflow: hidden;
}
.preview-card__thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.preview-card.is-error .preview-card__thumb {
  background: #fdecea;
  border-color: #f5c2c0;
  color: #c0392b;
}
.preview-card.is-error .preview-card__caption {
  color: #c0392b;
}
.preview-card__page {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 2px;
}
.preview-card__meta {
  font-size: 12px;
  color: var(--color-generate-dark);
  font-weight: 600;
  margin-bottom: 6px;
}
.preview-card__caption {
  font-size: 11px;
  color: var(--color-text-muted);
  line-height: 1.5;
}

.app-footer {
  max-width: 1160px;
  margin: 0 auto;
  padding: 16px 24px 40px;
  text-align: center;
}
.app-footer p {
  font-size: 12px;
  color: var(--color-text-muted);
}