/* ============================================================
   课题集 · 基础结构层
   视觉变量（颜色 / 字体 / 圆角 / 阴影）由 theme-*.css 提供
   ============================================================ */

:root {
  --font-body: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-display: var(--font-body);
  --font-mono: ui-monospace, "SF Mono", Menlo, monospace;
  --bg: #f5f5f5;
  --bg-elevated: #ffffff;
  --ink: #1a1a1a;
  --ink-soft: #555555;
  --ink-faint: #999999;
  --line: rgba(0, 0, 0, 0.12);
  --accent: #2563eb;
  --accent-ink: #ffffff;
  --accent-soft: rgba(37, 99, 235, 0.08);
  --danger: #c0392b;
  --ok: #1e8e5a;
  --radius: 10px;
  --radius-lg: 16px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.1);
  --page-max: 1240px;
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  min-height: 100vh;
}

::selection {
  background: var(--accent);
  color: var(--accent-ink);
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 8px 16px;
  z-index: 100;
}

.skip-link:focus {
  left: 8px;
  top: 8px;
}

/* ---------- 头部 ---------- */

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--bg-elevated);
  position: sticky;
  top: 0;
  z-index: 20;
}

.header-inner {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--ink);
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--accent-ink);
  font-weight: 700;
  font-size: 18px;
  font-family: var(--font-display);
}

.brand-copy {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.brand-copy strong {
  font-size: 16px;
  font-family: var(--font-display);
}

.brand-copy small {
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 14px;
}

.header-actions a {
  color: var(--ink-soft);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--radius);
}

.header-actions a:hover {
  color: var(--accent);
  background: var(--accent-soft);
}

/* ---------- 页面骨架 ---------- */

.page-shell {
  max-width: var(--page-max);
  margin: 0 auto;
  padding: 32px 24px 64px;
}

.intro {
  margin-bottom: 32px;
  max-width: 720px;
}

.eyebrow {
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin: 0 0 8px;
  font-family: var(--font-mono);
}

.intro h1 {
  font-family: var(--font-display);
  font-size: clamp(28px, 4.5vw, 44px);
  line-height: 1.2;
  margin: 0 0 12px;
  letter-spacing: -0.01em;
}

.intro h1 span {
  color: var(--accent);
}

.intro-copy {
  color: var(--ink-soft);
  margin: 0;
  font-size: 15px;
}

.workspace-grid {
  display: grid;
  grid-template-columns: minmax(340px, 460px) 1fr;
  gap: 24px;
  align-items: start;
}

.panel {
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow);
}

.form-panel {
  position: sticky;
  top: 84px;
}

.panel-heading {
  margin-bottom: 16px;
}

.panel-heading h2 {
  margin: 0;
  font-size: 18px;
  font-family: var(--font-display);
}

.panel-heading p {
  margin: 2px 0 0;
  font-size: 13px;
  color: var(--ink-faint);
}

/* ---------- 提交方式切换 ---------- */

.mode-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 4px;
  margin-bottom: 16px;
}

.mode-tab {
  font: inherit;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink-soft);
  background: transparent;
  border: none;
  border-radius: calc(var(--radius) - 2px);
  padding: 8px 12px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, box-shadow 0.15s;
}

.mode-tab:hover {
  color: var(--ink);
}

.mode-tab.is-active {
  background: var(--bg-elevated);
  color: var(--accent);
  box-shadow: var(--shadow);
}

/* 拖入文档模式：AI 整理完成前只显示拖拽区 */
.form-panel[data-mode="upload"] #topic-form {
  display: none;
}

.form-panel[data-mode="upload"] #topic-form.is-ai-ready {
  display: block;
}

/* 手动填写模式：只显示表单 */
.form-panel[data-mode="manual"] .upload-only {
  display: none;
}

/* ---------- 拖拽上传区 ---------- */

.dropzone {
  border: 1.5px dashed var(--line);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s, transform 0.15s;
  background: var(--bg);
}

.dropzone:hover,
.dropzone:focus-visible,
.dropzone.is-dragover {
  border-color: var(--accent);
  background: var(--accent-soft);
  outline: none;
}

.dropzone.is-dragover {
  transform: scale(1.01);
}

.dropzone.is-busy {
  pointer-events: none;
  opacity: 0.75;
}

.dropzone.is-busy .dropzone-icon svg {
  animation: dropzone-pulse 1s ease-in-out infinite;
}

@keyframes dropzone-pulse {
  0%, 100% { transform: translateY(0); opacity: 1; }
  50% { transform: translateY(-4px); opacity: 0.6; }
}

.dropzone.is-disabled {
  opacity: 0.55;
}

.dropzone-icon svg {
  width: 34px;
  height: 34px;
  color: var(--accent);
}

.dropzone-title {
  margin: 8px 0 4px;
  font-weight: 600;
  font-size: 15px;
}

.dropzone-hint {
  margin: 0;
  font-size: 12.5px;
  color: var(--ink-faint);
}

.dropzone-status {
  margin: 10px 0 0;
  font-size: 13px;
  color: var(--ink-soft);
  min-height: 0;
}

.dropzone-status:empty {
  display: none;
}

.dropzone-status.is-success {
  color: var(--ok);
}

.dropzone-status.is-error {
  color: var(--danger);
}

.paste-box {
  margin-top: 14px;
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

.paste-box label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-soft);
  margin-bottom: 8px;
}

.paste-box textarea {
  width: 100%;
  font: inherit;
  font-size: 13.5px;
  color: var(--ink);
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 9px 12px;
  resize: vertical;
  margin-bottom: 8px;
}

.paste-box textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

/* ---------- 表单 ---------- */

.field-group {
  margin-bottom: 14px;
}

.field-group label {
  display: block;
  font-size: 13.5px;
  font-weight: 600;
  margin-bottom: 6px;
}

.required-mark {
  color: var(--danger);
}

.field-group input,
.field-group select,
.field-group textarea {
  width: 100%;
  font: inherit;
  font-size: 14px;
  color: var(--ink);
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 9px 12px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.field-group textarea {
  resize: vertical;
  min-height: 64px;
}

.field-group input:focus,
.field-group select:focus,
.field-group textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.field-group .is-ai-filled {
  border-color: var(--ok);
  background: color-mix(in srgb, var(--ok) 5%, var(--bg-elevated));
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.extra-fields {
  border-top: 1px solid var(--line);
  padding-top: 12px;
  margin-bottom: 14px;
}

.extra-fields summary {
  cursor: pointer;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink-soft);
  margin-bottom: 12px;
}

.extra-fields summary:hover {
  color: var(--accent);
}

.form-actions {
  display: flex;
  gap: 10px;
  align-items: center;
}

.button {
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  border-radius: var(--radius);
  border: 1px solid transparent;
  padding: 10px 20px;
  cursor: pointer;
  transition: transform 0.12s, box-shadow 0.15s, background 0.15s, opacity 0.15s;
}

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

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

.button-primary {
  background: var(--accent);
  color: var(--accent-ink);
  box-shadow: var(--shadow);
}

.button-primary:hover:not(:disabled) {
  box-shadow: var(--shadow-lg);
}

.button-secondary {
  background: var(--bg-elevated);
  color: var(--accent);
  border-color: var(--accent);
}

.button-quiet {
  background: transparent;
  color: var(--ink-soft);
}

.button-quiet:hover {
  color: var(--ink);
  background: var(--accent-soft);
}

.text-button {
  font: inherit;
  background: none;
  border: none;
  color: var(--accent);
  cursor: pointer;
  text-decoration: underline;
  padding: 0;
}

.form-status {
  margin: 10px 0 0;
  font-size: 13.5px;
  min-height: 0;
}

.form-status:empty {
  display: none;
}

.form-status.is-success {
  color: var(--ok);
}

.form-status.is-error {
  color: var(--danger);
}

/* ---------- 汇总区 ---------- */

.collection-area {
  display: flex;
  flex-direction: column;
  gap: 20px;
  min-width: 0;
}

.day-banner {
  background: var(--accent-soft);
  border: 1px solid var(--accent);
  border-radius: var(--radius-lg);
  padding: 16px 20px;
}

.day-banner-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: 6px;
}

.day-banner p {
  margin: 0;
  font-size: 13.5px;
  color: var(--ink-soft);
}

.day-banner .day-banner-requirement {
  margin-top: 6px;
  font-weight: 600;
  color: var(--ink);
}

.topic-day {
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--accent);
  color: var(--accent-ink);
  font-family: var(--font-mono);
}

.list-heading {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
  flex-wrap: wrap;
}

.list-heading .panel-heading {
  margin-bottom: 0;
}

.toolbar {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin: 16px 0;
}

.search-box {
  position: relative;
  flex: 1;
  min-width: 200px;
}

.search-box svg {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  stroke: var(--ink-faint);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
}

.search-box input {
  width: 100%;
  font: inherit;
  font-size: 14px;
  padding: 9px 12px 9px 36px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  color: var(--ink);
}

.toolbar select {
  font: inherit;
  font-size: 13.5px;
  padding: 9px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  color: var(--ink);
}

.search-box input:focus,
.toolbar select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.inline-error {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  background: color-mix(in srgb, var(--danger) 8%, var(--bg-elevated));
  border: 1px solid color-mix(in srgb, var(--danger) 30%, transparent);
  color: var(--danger);
  border-radius: var(--radius);
  padding: 10px 14px;
  font-size: 13.5px;
  margin-bottom: 12px;
}

.loading-state {
  padding: 40px 0;
  text-align: center;
  color: var(--ink-faint);
  font-size: 14px;
}

.empty-state {
  text-align: center;
  padding: 48px 20px;
}

.empty-icon {
  display: inline-grid;
  place-items: center;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 24px;
  font-family: var(--font-display);
}

.empty-state h3 {
  margin: 14px 0 6px;
  font-family: var(--font-display);
}

.empty-state p {
  margin: 0;
  color: var(--ink-faint);
  font-size: 14px;
}

/* ---------- 课题卡片 ---------- */

.topics-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.topic-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 18px 20px;
  background: var(--bg-elevated);
  transition: box-shadow 0.15s, transform 0.15s;
}

.topic-card:hover {
  box-shadow: var(--shadow-lg);
}

.topic-topline {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
}

.topic-badges {
  display: flex;
  gap: 8px;
}

.topic-category,
.topic-status {
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--ink-soft);
}

.topic-category {
  background: var(--accent-soft);
  color: var(--accent);
  border-color: transparent;
}

.topic-status[data-status="待评审"] { color: #d97706; border-color: currentColor; }
.topic-status[data-status="已立项"] { color: #2563eb; border-color: currentColor; }
.topic-status[data-status="进行中"] { color: #1e8e5a; border-color: currentColor; }
.topic-status[data-status="已归档"] { color: #6b7280; border-color: currentColor; }

.topic-topline time {
  font-size: 12px;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}

.topic-card h3 {
  margin: 0 0 6px;
  font-size: 16.5px;
  font-family: var(--font-display);
}

.topic-description {
  margin: 0 0 10px;
  font-size: 14px;
  color: var(--ink-soft);
  white-space: pre-wrap;
}

.topic-details section {
  margin-bottom: 8px;
}

.topic-details h4 {
  margin: 0 0 2px;
  font-size: 12.5px;
  color: var(--ink-faint);
  font-weight: 600;
}

.topic-details p {
  margin: 0;
  font-size: 13.5px;
  color: var(--ink-soft);
  white-space: pre-wrap;
}

.topic-versions {
  margin-top: 6px;
}

.topic-versions summary {
  cursor: pointer;
  font-size: 12.5px;
  color: var(--ink-faint);
}

.topic-versions summary:hover {
  color: var(--accent);
}

.version-item {
  margin-top: 8px;
  padding: 10px 12px;
  border-left: 2px solid var(--line);
  background: var(--bg);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.version-item time {
  display: block;
  font-size: 11.5px;
  color: var(--ink-faint);
  font-family: var(--font-mono);
}

.version-item strong {
  display: block;
  font-size: 13px;
  margin: 2px 0;
}

.version-item p {
  margin: 0;
  font-size: 12.5px;
  color: var(--ink-soft);
  white-space: pre-wrap;
}

.topic-card footer {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
}

.avatar {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 14px;
  flex-shrink: 0;
}

.topic-card footer strong {
  display: block;
  font-size: 13.5px;
}

.topic-card footer span:not(.avatar) {
  font-size: 12.5px;
  color: var(--ink-faint);
}

/* ---------- 登录 / 注册 ---------- */

.auth-screen {
  min-height: calc(100vh - 140px);
  display: grid;
  place-items: center;
  padding: 32px 20px;
}

.auth-screen[hidden] {
  display: none;
}

.auth-panel {
  width: 100%;
  max-width: 400px;
}

.auth-panel h1 {
  font-family: var(--font-display);
  font-size: 24px;
  margin: 0 0 8px;
}

.auth-copy {
  margin: 0 0 18px;
  font-size: 13.5px;
  color: var(--ink-soft);
}

.user-chip {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink);
  background: var(--accent-soft);
  border-radius: 999px;
  padding: 5px 14px;
}

/* ---------- 页脚 ---------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding: 20px 24px;
  text-align: center;
  font-size: 12.5px;
  color: var(--ink-faint);
}

/* ---------- 联合品牌 logo ---------- */

.co-brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.co-brand-logo {
  height: 26px;
  width: auto;
  object-fit: contain;
  display: block;
}

.co-brand-logo.logo-21vianet { height: 34px; }
.co-brand-logo.logo-whaty { height: 17px; }
.co-brand-logo.logo-cloudwave { height: 24px; }

.co-brand-divider {
  width: 1px;
  height: 20px;
  background: var(--line);
}

.footer-brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  margin-bottom: 10px;
}

.footer-brand .co-brand-logo {
  height: 22px;
  opacity: 0.85;
}

.footer-brand .logo-21vianet { height: 28px; }
.footer-brand .logo-whaty { height: 15px; }
.footer-brand .logo-cloudwave { height: 20px; }

/* ---------- 响应式 ---------- */

@media (max-width: 960px) {
  .workspace-grid {
    grid-template-columns: 1fr;
  }

  .form-panel {
    position: static;
  }

  .co-brand {
    display: none;
  }
}

@media (max-width: 560px) {
  .field-row {
    grid-template-columns: 1fr;
  }

  .page-shell {
    padding: 20px 14px 48px;
  }

  .panel {
    padding: 18px;
  }
}