:root {
  color-scheme: light;
  --bg: #f4f7fb;
  --surface: #ffffff;
  --surface-2: #eef4ff;
  --text: #172033;
  --muted: #5d6b82;
  --line: #d8e1ee;
  --primary: #1d4ed8;
  --primary-strong: #163ea8;
  --danger: #b42318;
  --good: #0f7a3d;
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100dvh;
  color: var(--text);
  background: var(--bg);
}

a {
  color: inherit;
}

button,
input,
select {
  font: inherit;
}

button,
.button {
  min-height: 46px;
  border: 0;
  border-radius: 7px;
  padding: 10px 16px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: #fff;
  background: var(--primary);
  text-decoration: none;
  cursor: pointer;
  touch-action: manipulation;
  transition: background-color 160ms ease, opacity 160ms ease, box-shadow 160ms ease;
}

button:hover,
.button:hover {
  background: var(--primary-strong);
}

button.secondary,
.button.secondary {
  color: var(--primary);
  background: var(--surface-2);
}

button.secondary:hover,
.button.secondary:hover {
  background: #dfeaff;
}

button.danger,
.button.danger {
  color: #fff;
  background: var(--danger);
}

button.danger:hover,
.button.danger:hover {
  background: #8a1f17;
}

button:disabled {
  cursor: wait;
  opacity: 0.6;
}

button[data-busy="true"] {
  pointer-events: none;
}

button:focus-visible,
.button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(29, 78, 216, 0.28);
  outline-offset: 2px;
}

svg {
  width: 20px;
  height: 20px;
  flex: 0 0 auto;
}

input,
select,
textarea {
  width: 100%;
  min-height: 46px;
  border: 1px solid var(--line);
  border-radius: 7px;
  padding: 10px 12px;
  color: var(--text);
  background: #fff;
}

textarea {
  min-height: 110px;
  resize: vertical;
  line-height: 1.5;
}

label {
  display: grid;
  gap: 6px;
  color: var(--muted);
  font-size: 14px;
}

.field-hint {
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.field-error {
  color: var(--danger);
  font-size: 13px;
  line-height: 1.5;
}

.password-rules {
  display: grid;
  gap: 6px;
  border: 1px solid #c7d7fe;
  border-radius: 8px;
  padding: 12px;
  color: #294067;
  background: #f2f6ff;
  font-size: 14px;
  line-height: 1.5;
}

.portal,
.workspace {
  width: min(1120px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 24px 0 40px;
}

.portal {
  min-height: 100dvh;
  display: grid;
  align-content: center;
  gap: 24px;
}

.portal-header,
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  min-height: 58px;
  padding: 8px 0;
  background: rgba(244, 247, 251, 0.94);
  backdrop-filter: blur(10px);
}

.portal-header {
  justify-content: flex-start;
}

.portal-header img,
.brand img {
  width: 52px;
  height: 52px;
  object-fit: contain;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1 {
  font-size: clamp(24px, 3vw, 34px);
}

h2 {
  font-size: 20px;
}

h3 {
  font-size: 17px;
}

p,
.muted {
  color: var(--muted);
  line-height: 1.6;
}

.entry-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.entry-panel,
.panel,
.room-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: 0 10px 24px rgba(20, 36, 64, 0.06);
}

.entry-panel {
  min-height: 150px;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 22px;
  text-decoration: none;
}

.entry-panel svg {
  width: 30px;
  height: 30px;
  color: var(--primary);
}

.entry-panel strong {
  display: block;
  font-size: 20px;
  margin-bottom: 6px;
}

.entry-panel small {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.5;
}

.primary-entry {
  border-color: #b9cdfd;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  font-weight: 700;
}

.top-actions,
.row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.top-actions {
  margin-left: auto;
  justify-content: flex-end;
  flex-wrap: nowrap;
}

.top-actions .muted {
  max-width: 12em;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#refreshRoomsBtn {
  flex: 0 0 auto;
}

.stack {
  display: grid;
  gap: 14px;
}

.grid {
  display: grid;
  grid-template-columns: minmax(280px, 390px) 1fr;
  gap: 16px;
  align-items: start;
}

.course-picker {
  display: grid;
  gap: 10px;
}

.checkbox-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 8px;
}

.checkbox {
  width: auto;
  min-height: 36px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 10px;
  border: 1px solid var(--line);
  border-radius: 7px;
  color: var(--text);
  background: #fff;
}

.checkbox input {
  width: auto;
  min-height: auto;
}

.ai-conversation {
  display: grid;
  gap: 12px;
}

.ai-message-list {
  max-height: 420px;
  overflow: auto;
  display: grid;
  gap: 10px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbff;
}

.ai-message {
  max-width: min(86%, 680px);
  display: grid;
  gap: 5px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.ai-message.user {
  justify-self: end;
  border-color: #bdd0ff;
  background: #edf3ff;
}

.ai-message.assistant {
  justify-self: start;
}

.ai-message.error {
  justify-self: start;
  border-color: #ffd1d1;
  background: #fff1f1;
}

.ai-message p {
  color: var(--text);
  white-space: pre-wrap;
  word-break: break-word;
}

.ai-message-meta {
  min-height: 18px;
  color: var(--muted);
  font-size: 12px;
}

.ai-composer {
  display: grid;
  gap: 10px;
}

.ai-composer textarea {
  min-height: 96px;
}

.ai-mode-bar,
.ai-mode-buttons {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.ai-mode-bar {
  justify-content: space-between;
}

.ai-mode-button {
  min-height: 40px;
}

.ai-mode-button.active {
  color: #fff;
  background: var(--primary);
}

.ai-image-result {
  display: block;
  width: min(100%, 520px);
  max-height: 520px;
  object-fit: contain;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.ai-image-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
}

.image-preview-button {
  width: fit-content;
  max-width: 100%;
  height: auto;
  min-height: 0;
  padding: 0;
  border: 0;
  border-radius: 8px;
  color: inherit;
  background: transparent;
}

.image-preview-button:hover {
  background: transparent;
  box-shadow: 0 0 0 3px rgba(29, 78, 216, 0.18);
}

.image-viewer {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: grid;
  place-items: center;
  padding: 24px;
  background: rgba(10, 18, 32, 0.86);
}

.image-viewer img {
  max-width: min(96vw, 1100px);
  max-height: 92vh;
  object-fit: contain;
  border-radius: 8px;
  background: #fff;
}

.image-viewer-close {
  position: fixed;
  top: 16px;
  right: 16px;
  width: 44px;
  height: 44px;
  min-height: 44px;
  padding: 0;
  font-size: 28px;
  line-height: 1;
  background: rgba(255, 255, 255, 0.18);
}

.classroom-console {
  border: 1px solid #c7d7fe;
  border-radius: 8px;
  padding: 14px;
  background: #f8fbff;
}

.console-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.submission-grid {
  display: grid;
  gap: 12px;
}

.submission-card {
  display: grid;
  grid-template-columns: minmax(180px, 260px) 1fr;
  gap: 14px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.submission-image {
  display: block;
  width: 100%;
  aspect-ratio: 1;
  object-fit: contain;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.submission-fields {
  display: grid;
  gap: 10px;
}

.submission-fields .muted {
  max-height: 5em;
  overflow: auto;
  padding: 8px;
  border-radius: 7px;
  background: #f8fbff;
  font-size: 13px;
  word-break: break-word;
}

.submission-group-card {
  display: grid;
  gap: 12px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
}

.submission-group-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
}

.submission-group-head h4 {
  margin: 0 0 4px;
  font-size: 16px;
}

.submission-selection-help {
  margin: 0;
  padding: 9px 10px;
  border-radius: 7px;
  color: #334155;
  background: #f1f5f9;
  font-size: 13px;
}

.report-download-status:not(:empty) {
  margin: 0;
  padding: 9px 10px;
  border-radius: 7px;
  color: #31546f;
  background: #eef7ff;
  font-weight: 700;
}

.report-download-status[data-tone="done"] {
  color: #12655b;
  background: #e9f8f2;
}

.report-download-status[data-tone="error"] {
  color: #9f2d24;
  background: #fff0ee;
}

.submission-group-fields {
  display: grid;
  grid-template-columns: minmax(160px, 1fr) minmax(140px, .7fr);
  gap: 10px;
}

.submission-work-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
}

.submission-work-card {
  display: grid;
  gap: 8px;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fbff;
}

.submission-work-card .submission-image {
  aspect-ratio: 1;
}

.preview-only-work-grid {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.preview-only-work-card .submission-image {
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.preview-only-work-copy {
  display: grid;
  gap: 4px;
}

.preview-only-work-copy p {
  margin: 0;
}

.preview-only-caption {
  overflow-wrap: anywhere;
}

.work-select {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  font-weight: 800;
  color: var(--ink);
}

.work-select input {
  width: auto;
}

.panel {
  padding: 18px;
}

.notice {
  border-radius: 7px;
  padding: 11px 13px;
  color: #21416c;
  background: #eef6ff;
  line-height: 1.5;
}

.notice.error {
  color: #8a1f17;
  background: #fff1f1;
}

.hidden {
  display: none !important;
}

.room-code {
  font-size: clamp(42px, 8vw, 72px);
  font-weight: 800;
  letter-spacing: 0;
  line-height: 1;
}

.room-code-block {
  display: grid;
  gap: 10px;
}

.room-code-actions {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.lesson-list,
.room-list,
.tool-list,
.feature-list {
  display: grid;
  gap: 10px;
}

.room-card {
  padding: 14px;
}

.room-card-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.tag {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  border-radius: 999px;
  padding: 4px 10px;
  color: #294067;
  background: #edf3ff;
  font-size: 13px;
}

.tool-link {
  min-height: 58px;
  border: 1px solid var(--line);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  text-decoration: none;
  background: #fff;
}

.tool-link strong {
  display: block;
  margin-top: 4px;
}

.tool-link svg {
  color: var(--primary);
}

.courseware-link {
  border-color: #b7c8f7;
  background: #f7faff;
}

.classroom-control-section {
  gap: 8px;
}

.classroom-control-row {
  display: grid;
  grid-template-columns: minmax(128px, 1fr) auto auto;
  gap: 8px;
  align-items: center;
}

.classroom-control-row .compact {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.classroom-control-row button {
  min-height: 38px;
  padding: 8px 12px;
}

.classroom-watermark {
  position: fixed;
  inset: 0;
  z-index: 20;
  pointer-events: none;
  overflow: hidden;
  opacity: 0.075;
}

.classroom-watermark span {
  position: absolute;
  color: #172033;
  font-size: 14px;
  font-weight: 700;
  line-height: 1.4;
  white-space: nowrap;
  transform: rotate(-28deg);
}

.student-room {
  min-height: 100dvh;
  display: grid;
  align-content: center;
}

.room-input {
  text-transform: uppercase;
  font-size: 28px;
  text-align: center;
  letter-spacing: 0;
  font-weight: 700;
}

.full-width {
  width: 100%;
}

@media (max-width: 900px) {
  .entry-grid,
  .grid {
    grid-template-columns: 1fr;
  }

  .portal,
  .workspace {
    width: min(100vw - 20px, 760px);
    padding-top: 14px;
  }

  .ai-message {
    max-width: 94%;
  }

  .ai-mode-bar {
    align-items: stretch;
  }

  .ai-mode-buttons,
  .ai-mode-bar > button {
    width: 100%;
  }

  .console-head {
    align-items: stretch;
    flex-direction: column;
  }

  .submission-group-head {
    flex-direction: column;
  }

  .submission-group-fields {
    grid-template-columns: 1fr;
  }

  .submission-card {
    grid-template-columns: 1fr;
  }

  .classroom-control-row {
    grid-template-columns: 1fr;
  }

  .classroom-control-row button {
    width: 100%;
  }
}