:root {
  --color-bg: #f6f7fb;
  --color-surface: #ffffff;
  --color-border: #e6e8f0;
  --color-text: #1c2030;
  --color-text-muted: #63687a;

  --color-assistant: #6c5ce7;
  --color-assistant-bg: #f4f1ff;
  --color-assistant-dark: #5a48d1;

  --color-generate: #00b894;
  --color-generate-bg: #eafaf5;
  --color-generate-dark: #00967a;

  --color-danger: #c0392b;
  --color-danger-bg: #fdecec;
  --color-danger-border: #f3c6c6;

  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 20px;

  --shadow-sm: 0 1px 3px rgba(20, 20, 40, 0.05);
  --shadow-md: 0 8px 24px rgba(24, 24, 48, 0.07);
  --shadow-lg: 0 16px 40px rgba(24, 24, 48, 0.09);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN",
    "Hiragino Sans", "Yu Gothic Medium", "Yu Gothic", "Noto Sans JP", Meiryo, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: linear-gradient(180deg, #f8f9fc 0%, #eef0f7 100%);
  background-attachment: fixed;
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* Header */
.app-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 rgba(20, 20, 40, 0.05);
  padding: 18px 24px;
}

.app-header__inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 14px;
}

.app-header__logo {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  background: linear-gradient(135deg, var(--color-assistant-bg), var(--color-generate-bg));
  border-radius: var(--radius-sm);
}

.app-header__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.app-header__title {
  font-size: 20px;
  font-weight: 800;
  margin: 0;
  letter-spacing: 0.01em;
}

.app-header__subtitle {
  margin: 0;
  font-size: 12.5px;
  color: var(--color-text-muted);
}

@media (max-width: 480px) {
  .app-header__subtitle {
    display: none;
  }
}

/* Page lead */
.page-lead {
  max-width: 1200px;
  margin: 28px auto 0;
  padding: 0 20px;
  text-align: center;
  color: var(--color-text-muted);
  font-size: 15px;
}

@media (max-width: 600px) {
  .page-lead {
    font-size: 13.5px;
    margin-top: 22px;
  }
}

/* Layout */
.main-layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 22px 20px 64px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  align-items: start;
}

@media (max-width: 900px) {
  .main-layout {
    grid-template-columns: 1fr;
    padding: 18px 16px 40px;
    gap: 20px;
  }
}

/* Panel */
.panel {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: 32px;
  border-top: 4px solid transparent;
  transition: box-shadow 0.2s ease;
}

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

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

@media (min-width: 901px) {
  .panel:hover {
    box-shadow: var(--shadow-lg);
  }
}

@media (max-width: 600px) {
  .panel {
    padding: 22px 18px;
    border-radius: var(--radius-md);
  }
}

.panel__badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--color-assistant-dark);
  background: var(--color-assistant-bg);
  padding: 5px 12px;
  border-radius: 999px;
  margin-bottom: 14px;
}

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

.panel__title {
  font-size: 21px;
  font-weight: 800;
  margin: 0 0 10px;
  letter-spacing: 0.01em;
}

.panel__desc {
  color: var(--color-text-muted);
  font-size: 14px;
  line-height: 1.75;
  margin: 0 0 26px;
}

/* Form */
.form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 7px;
}

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

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

.field__label {
  font-size: 13px;
  font-weight: 600;
  color: var(--color-text);
}

.select,
.textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  font-family: inherit;
  line-height: 1.6;
  background: 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='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2363687a' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  background-size: 16px;
  cursor: pointer;
}

.textarea {
  min-height: 108px;
}

.select:hover,
.textarea:hover {
  border-color: #c7cbdb;
}

.select:focus,
.textarea:focus {
  outline: none;
  border-color: var(--color-assistant);
  box-shadow: 0 0 0 4px rgba(108, 92, 231, 0.14);
}

.panel--generate .textarea:focus,
.panel--generate .select:focus {
  border-color: var(--color-generate);
  box-shadow: 0 0 0 4px rgba(0, 184, 148, 0.14);
}

/* Upload box */
.upload-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  padding: 30px 16px;
  cursor: pointer;
  text-align: center;
  background: #fbfbff;
  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: 26px;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface);
  border-radius: 50%;
  box-shadow: var(--shadow-sm);
}

.upload-box__text {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--color-text);
}

.upload-box__hint {
  font-size: 11.5px;
  color: var(--color-text-muted);
}

.field__note {
  font-size: 11.5px;
  color: var(--color-text-muted);
  margin: 2px 0 0;
}

/* Buttons */
.btn {
  border: none;
  border-radius: var(--radius-sm);
  padding: 15px 20px;
  min-height: 50px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.01em;
  cursor: pointer;
  color: #fff;
  transition: transform 0.1s ease, box-shadow 0.15s ease, opacity 0.15s ease;
  margin-top: 4px;
}

.btn:hover {
  transform: translateY(-1px);
  opacity: 0.95;
}

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

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn:focus-visible {
  outline: 3px solid rgba(108, 92, 231, 0.4);
  outline-offset: 2px;
}

.btn--assistant {
  background: linear-gradient(135deg, var(--color-assistant), var(--color-assistant-dark));
  box-shadow: 0 8px 20px rgba(108, 92, 231, 0.3);
}

.btn--generate {
  background: linear-gradient(135deg, var(--color-generate), var(--color-generate-dark));
  box-shadow: 0 8px 20px rgba(0, 184, 148, 0.3);
}

.btn--generate:focus-visible {
  outline-color: rgba(0, 184, 148, 0.4);
}

/* Result box (assistant) */
.result-box {
  margin-top: 24px;
  background: var(--color-assistant-bg);
  border-left: 4px solid var(--color-assistant);
  border-radius: var(--radius-md);
  padding: 18px 20px;
}

.result-box__label {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-assistant-dark);
  margin-bottom: 8px;
  letter-spacing: 0.04em;
}

.result-box__text {
  font-size: 13.5px;
  color: var(--color-text);
  line-height: 1.8;
  margin: 0;
  white-space: pre-wrap;
}

.result-box--error {
  background: var(--color-danger-bg);
  border-left-color: var(--color-danger);
}

.result-box--error .result-box__label {
  color: var(--color-danger);
}

/* Notice box (generate) */
.notice-box {
  margin-top: 24px;
  background: #fff8e6;
  border-left: 4px solid #e0b23c;
  border-radius: var(--radius-md);
  padding: 16px 20px;
  font-size: 13.5px;
  color: #8a6d1f;
  line-height: 1.8;
}

.notice-box--error {
  background: var(--color-danger-bg);
  border-left-color: var(--color-danger);
  color: var(--color-danger);
}

/* Preview box (generate) */
.preview-box {
  margin-top: 24px;
}

.preview-box__label {
  font-size: 12px;
  font-weight: 700;
  color: var(--color-generate-dark);
  margin-bottom: 14px;
  letter-spacing: 0.04em;
}

.preview-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
}

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

.preview-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface);
  display: flex;
  flex-direction: column;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

@media (min-width: 601px) {
  .preview-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
  }
}

.preview-card__thumb {
  background: repeating-linear-gradient(
    45deg,
    #eef7f4,
    #eef7f4 10px,
    #e4f3ee 10px,
    #e4f3ee 20px
  );
  height: 128px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-size: 30px;
  color: var(--color-generate-dark);
}

.preview-card__thumb span {
  font-size: 11.5px;
  font-weight: 600;
}

.preview-card__meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 14px 0;
  font-size: 12px;
  font-weight: 700;
}

.preview-card__page {
  color: var(--color-text);
}

.preview-card__panels {
  color: var(--color-generate-dark);
  background: var(--color-generate-bg);
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 11px;
}

.preview-card__note {
  font-size: 11.5px;
  color: var(--color-text-muted);
  padding: 8px 14px 14px;
  margin: 0;
  line-height: 1.6;
}

/* Footer */
.app-footer {
  text-align: center;
  font-size: 12px;
  color: var(--color-text-muted);
  padding: 24px 20px 32px;
  border-top: 1px solid var(--color-border);
}

.app-footer p {
  max-width: 720px;
  margin: 0 auto;
  line-height: 1.7;
}