:root {
  --color-primary: #155eef;
  --color-primary-dark: #114bc1;
  --color-primary-soft: #edf4ff;
  --color-accent: #13a38b;
  --color-success: #087e62;
  --color-warning: #a15c00;
  --color-warning-soft: #fff7e8;
  --color-error: #c4320a;
  --color-error-soft: #fff1ed;
  --color-text: #16202f;
  --color-text-secondary: #526071;
  --color-text-tertiary: #778397;
  --color-border: #d9e1ec;
  --color-border-strong: #b8c5d6;
  --color-surface: #ffffff;
  --color-background: #f4f7fb;
  --color-code: #101828;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-base: 12px;
  --spacing-md: 16px;
  --spacing-lg: 20px;
  --spacing-xl: 24px;
  --spacing-2xl: 32px;
  --spacing-3xl: 48px;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-card: 0 8px 30px rgba(29, 41, 57, 0.08);
  --transition: 180ms ease;
  --header-height: 72px;
  font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  color: var(--color-text);
  background: var(--color-background);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; height: auto; background: var(--color-background); line-height: 1.6; }
button, input, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button:focus-visible, a:focus-visible, input:focus-visible, textarea:focus-visible, summary:focus-visible {
  outline: 3px solid rgba(21, 94, 239, 0.24);
  outline-offset: 2px;
}

.skip-link { position: fixed; z-index: 100; top: var(--spacing-sm); left: var(--spacing-sm); transform: translateY(-160%); padding: var(--spacing-sm) var(--spacing-md); border-radius: var(--radius-sm); color: var(--color-surface); background: var(--color-primary); }
.skip-link:focus { transform: none; }
.site-header { height: var(--header-height); border-bottom: 1px solid var(--color-border); background: rgba(255,255,255,.96); position: sticky; top: 0; z-index: 20; backdrop-filter: blur(10px); }
.header-inner { max-width: 1440px; height: 100%; margin: 0 auto; padding: 0 var(--spacing-xl); display: flex; align-items: center; gap: var(--spacing-base); }
.brand-mark { width: 42px; height: 42px; display: grid; place-items: center; flex: none; border-radius: var(--radius-md); color: var(--color-surface); background: linear-gradient(135deg, var(--color-primary), var(--color-accent)); font-weight: 800; }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 0; font-size: 22px; line-height: 1.2; }
.eyebrow { margin-bottom: 2px; color: var(--color-primary); font-size: 12px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.mobile-menu { display: none; margin-left: auto; border: 1px solid var(--color-border); border-radius: var(--radius-sm); padding: var(--spacing-sm) var(--spacing-base); background: var(--color-surface); color: var(--color-text); }

.page-shell { max-width: 1440px; min-height: calc(100vh - var(--header-height) - 72px); margin: 0 auto; padding: var(--spacing-xl); display: grid; grid-template-columns: 300px minmax(0, 1fr); gap: var(--spacing-xl); }
.catalog-sidebar, .question-panel { border: 1px solid var(--color-border); border-radius: var(--radius-lg); background: var(--color-surface); box-shadow: var(--shadow-card); }
.catalog-sidebar { align-self: start; position: sticky; top: calc(var(--header-height) + var(--spacing-xl)); max-height: calc(100vh - var(--header-height) - 2 * var(--spacing-xl)); overflow: auto; padding: var(--spacing-lg); }
.sidebar-heading, .section-heading { display: flex; justify-content: space-between; align-items: flex-start; gap: var(--spacing-md); }
.sidebar-heading h2 { margin-bottom: 0; font-size: 19px; }
.count-badge, .unofficial-badge, .task-type { white-space: nowrap; border-radius: 999px; padding: var(--spacing-xs) var(--spacing-sm); background: var(--color-primary-soft); color: var(--color-primary-dark); font-size: 12px; font-weight: 700; }
.status-message { color: var(--color-text-secondary); font-size: 14px; }
.question-list { display: grid; gap: var(--spacing-sm); }
.question-button { width: 100%; border: 1px solid transparent; border-radius: var(--radius-md); padding: var(--spacing-base); text-align: left; color: var(--color-text); background: transparent; cursor: pointer; transition: background var(--transition), border var(--transition); }
.question-button:hover { background: var(--color-background); }
.question-button[aria-current="true"] { border-color: #b2ccff; background: var(--color-primary-soft); }
.question-id { display: block; color: var(--color-primary); font-size: 12px; font-weight: 700; }
.question-name { display: block; margin-top: var(--spacing-xs); font-weight: 650; line-height: 1.4; }
.question-meta { display: block; margin-top: var(--spacing-xs); color: var(--color-text-tertiary); font-size: 12px; }
.question-panel { min-width: 0; padding: var(--spacing-2xl); }
.empty-state { min-height: 420px; display: grid; place-content: center; text-align: center; color: var(--color-text-secondary); }
.empty-icon { margin: 0 auto var(--spacing-md); width: 56px; height: 56px; display: grid; place-items: center; border-radius: 50%; background: var(--color-primary-soft); color: var(--color-primary); font-size: 28px; }

.question-hero { padding-bottom: var(--spacing-xl); border-bottom: 1px solid var(--color-border); }
.question-hero h2 { margin: var(--spacing-sm) 0; font-size: clamp(24px, 3vw, 34px); line-height: 1.3; }
.requirements-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--spacing-md); margin: var(--spacing-lg) 0; }
.requirement-block { padding: var(--spacing-md); border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-surface); }
.requirement-block p { white-space: pre-line; }
.question-navigation { display: flex; justify-content: space-between; gap: var(--spacing-md); margin-top: var(--spacing-xl); }
.hero-meta { display: flex; flex-wrap: wrap; gap: var(--spacing-sm); color: var(--color-text-secondary); font-size: 14px; }
.scenario { margin: var(--spacing-lg) 0 0; padding: var(--spacing-md) var(--spacing-lg); border-left: 4px solid var(--color-accent); border-radius: 0 var(--radius-md) var(--radius-md) 0; background: #f0fbf8; }
.review-notice, .notice { padding: var(--spacing-base) var(--spacing-md); border: 1px solid #fedf89; border-radius: var(--radius-md); background: var(--color-warning-soft); color: #72430d; }
.review-notice { margin-top: var(--spacing-md); }
.task-card, .attachments, .ai-panel { margin-top: var(--spacing-xl); border: 1px solid var(--color-border); border-radius: var(--radius-lg); padding: var(--spacing-xl); }
.task-card h3, .attachments h3, .ai-panel h3 { margin-bottom: var(--spacing-xs); font-size: 20px; }
.task-instructions { color: var(--color-text-secondary); }
.field-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--spacing-md); }
.form-field { display: grid; gap: var(--spacing-xs); }
.form-field label { font-weight: 650; }
.form-field input, .form-field textarea, #api-key { width: 100%; border: 1px solid var(--color-border-strong); border-radius: var(--radius-sm); padding: var(--spacing-sm) var(--spacing-base); color: var(--color-text); background: var(--color-surface); transition: border var(--transition), box-shadow var(--transition); }
.form-field textarea { min-height: 160px; resize: vertical; }
.form-field input:focus, .form-field textarea:focus, #api-key:focus { border-color: var(--color-primary); box-shadow: 0 0 0 3px rgba(21,94,239,.12); outline: none; }
.code-block { margin-top: var(--spacing-md); overflow: auto; border-radius: var(--radius-md); padding: var(--spacing-md); background: var(--color-code); color: #e6edf6; font: 13px/1.65 "Cascadia Code", Consolas, monospace; white-space: pre; }
.blank-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--spacing-md); margin-top: var(--spacing-lg); }
.rubric { margin: var(--spacing-md) 0 0; padding-left: var(--spacing-xl); color: var(--color-text-secondary); }
.draft-status { min-height: 22px; margin: var(--spacing-base) 0 0; color: var(--color-success); font-size: 13px; }
.answer-result { min-height: 20px; font-size: 13px; font-weight: 700; }
.answer-result.is-passed { color: var(--color-success); }
.answer-result.needs-change { color: var(--color-error); }
.check-answer { margin-top: var(--spacing-md); }
.check-summary { margin-top: var(--spacing-base); padding: var(--spacing-base); border-radius: var(--radius-md); background: var(--color-background); color: var(--color-text-secondary); }
.check-summary:empty { display: none; }
.check-summary p:last-child, .check-summary ul:last-child { margin-bottom: 0; }

.attachment-list { display: grid; gap: var(--spacing-sm); margin: 0; padding: 0; list-style: none; }
.attachment-item { display: flex; align-items: center; gap: var(--spacing-md); border: 1px solid var(--color-border); border-radius: var(--radius-md); padding: var(--spacing-base); }
.attachment-info { min-width: 0; flex: 1; }
.attachment-name { display: block; overflow-wrap: anywhere; font-weight: 650; }
.attachment-meta { color: var(--color-text-tertiary); font-size: 12px; }
.download-link { flex: none; color: var(--color-primary); font-weight: 650; }
.large-file { color: var(--color-warning); font-weight: 700; }

.api-settings { margin-top: var(--spacing-md); border: 1px solid var(--color-border); border-radius: var(--radius-md); padding: var(--spacing-base); }
.api-settings summary { cursor: pointer; font-weight: 700; }
.api-row { display: grid; grid-template-columns: auto minmax(200px, 1fr) auto auto; align-items: center; gap: var(--spacing-base); margin-top: var(--spacing-md); }
.checkbox-label { display: inline-flex; align-items: center; gap: var(--spacing-xs); }
.field-help { margin: var(--spacing-sm) 0 0; color: var(--color-text-tertiary); font-size: 12px; }
.ai-actions { display: flex; flex-wrap: wrap; gap: var(--spacing-sm); margin-top: var(--spacing-md); }
.button { border: 1px solid transparent; border-radius: var(--radius-sm); padding: var(--spacing-sm) var(--spacing-md); font-weight: 700; cursor: pointer; }
.button:disabled { cursor: not-allowed; opacity: .55; }
.button.primary { color: var(--color-surface); background: var(--color-primary); }
.button.primary:hover:not(:disabled) { background: var(--color-primary-dark); }
.button.secondary { border-color: var(--color-border-strong); color: var(--color-text); background: var(--color-surface); }
.button.danger { border-color: #fda29b; color: var(--color-error); background: var(--color-error-soft); }
.ai-output { min-height: 130px; max-height: 480px; overflow: auto; margin: var(--spacing-md) 0 0; border-radius: var(--radius-md); padding: var(--spacing-md); white-space: pre-wrap; overflow-wrap: anywhere; background: #f8fafc; color: var(--color-text); font: inherit; }
.site-footer { min-height: 72px; display: flex; justify-content: center; align-items: center; gap: var(--spacing-sm); padding: var(--spacing-md) var(--spacing-xl); border-top: 1px solid var(--color-border); color: var(--color-text-secondary); background: var(--color-surface); text-align: center; font-size: 13px; }
.site-footer strong { color: var(--color-warning); }

@media (max-width: 1100px) {
  .page-shell { grid-template-columns: 250px minmax(0, 1fr); padding: var(--spacing-lg); gap: var(--spacing-lg); }
  .question-panel { padding: var(--spacing-xl); }
  .field-grid, .blank-list { grid-template-columns: 1fr; }
  .api-row { grid-template-columns: 1fr; align-items: stretch; }
}

@media (max-width: 768px) {
  :root { --header-height: 64px; }
  .header-inner { padding: 0 var(--spacing-md); }
  .mobile-menu { display: block; }
  .page-shell { display: block; padding: var(--spacing-md); }
  .catalog-sidebar { display: none; position: static; max-height: none; margin-bottom: var(--spacing-md); }
  .requirements-grid { grid-template-columns: 1fr; }
  .catalog-sidebar.is-open { display: block; }
  .question-panel { padding: var(--spacing-md); border-radius: var(--radius-md); }
  .task-card, .attachments, .ai-panel { padding: var(--spacing-md); }
  .attachment-item { align-items: flex-start; flex-wrap: wrap; }
  .site-footer { align-items: flex-start; flex-direction: column; text-align: left; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; }
}