/* ========== 全局样式 ========== */
:root {
  --bg-primary: #1e1e1e;
  --bg-secondary: #252526;
  --bg-tertiary: #2d2d30;
  --text-primary: #d4d4d4;
  --text-secondary: #969696;
  --border-color: #3e3e42;
  --accent-primary: #0e639c;
  --accent-secondary: #1177bb;
  --success: #4ec9b0;
  --error: #f48771;
  --warning: #dcdcaa;
  --info: #569cd6;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
}

body.username-gate-pending > :not(.username-login) { visibility: hidden; }
body.username-locked { overflow: hidden; }
.username-login[hidden] { display: none; }
.username-login {
  position: fixed;
  inset: 0;
  z-index: 1000;
  padding: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10, 10, 12, .1);
  backdrop-filter: blur(2px);
}
.username-login-card {
  width: min(100%, 390px);
  padding: 30px;
  display: grid;
  gap: 15px;
  border: 1px solid var(--border-color);
  border-radius: 12px;
  background: rgba(37, 37, 38, .4);
  backdrop-filter: blur(9px);
  box-shadow: 0 14px 38px rgba(0, 0, 0, .2);
}
.username-login-card > img { width: 66px; height: 66px; margin: 0 auto; border-radius: 50%; }
.username-login-card h2 { color: var(--text-primary); text-align: center; font-size: 22px; }
.username-login-card > p:not(.username-login-status) { color: var(--text-secondary); text-align: center; font-size: 13px; }
.username-login-card label { display: grid; gap: 7px; color: var(--text-secondary); font-size: 13px; }
.username-login-card input {
  width: 100%;
  min-height: 42px;
  padding: 8px 11px;
  border: 1px solid var(--border-color);
  border-radius: 5px;
  outline: none;
  background: var(--bg-primary);
  color: var(--text-primary);
  font: inherit;
}
.username-login-card input:focus { border-color: var(--accent-primary); box-shadow: 0 0 0 3px rgba(14, 99, 156, .2); }
.username-login-card label[hidden] { display: none; }
.username-login-status { min-height: 19px; color: var(--error); font-size: 12px; text-align: left; }
.username-login-card .btn { min-height: 42px; }
.username-login-actions { display: flex; gap: 9px; }
.username-login-actions .btn { flex: 1; }
.username-login-actions .btn[hidden] { display: none; }

.container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ========== 头部导航 ========== */
.header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container {
  display: flex;
  align-items: center;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 20px;
  font-weight: 600;
  line-height: 1;
  white-space: nowrap;
  color: var(--text-primary);
}

.brand-logo {
  display: block;
  width: 38px;
  height: 38px;
  flex: 0 0 38px;
  object-fit: contain;
  border-radius: 50%;
}

.nav {
  display: flex;
  gap: 8px;
  flex: 1;
}
.exam-mode-badge { align-self: center; padding: 4px 9px; border: 1px solid rgba(244,135,113,.55); border-radius: 999px; background: rgba(244,135,113,.1); color: var(--error); font-size: 12px; font-weight: 600; white-space: nowrap; }
.exam-mode-badge[hidden], body.exam-mode .nav-link[data-view="problems"], body.exam-mode .nav-link[data-view="submissions"] { display: none; }

.nav-link {
  padding: 6px 16px;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 4px;
  transition: all 0.2s;
}

.nav-link:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.nav-link.active {
  background: var(--accent-primary);
  color: white;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--text-secondary);
  font-size: 14px;
}

.user-account { position: relative; }
.user-account[hidden] { display: none; }
.user-menu-trigger { padding: 6px 9px; display: flex; align-items: center; gap: 6px; border: 0; border-radius: 5px; background: transparent; color: var(--text-secondary); font: inherit; cursor: pointer; }
.user-account:hover .user-menu-trigger, .user-account:focus-within .user-menu-trigger { background: var(--bg-tertiary); color: var(--text-primary); }
.user-menu { position: absolute; z-index: 80; top: 100%; right: 0; width: 132px; padding: 5px; visibility: hidden; opacity: 0; transform: translateY(-4px); border: 1px solid var(--border-color); border-radius: 7px; background: var(--bg-secondary); box-shadow: 0 10px 28px rgba(0,0,0,.28); transition: 130ms ease; }
.user-account:hover .user-menu, .user-account:focus-within .user-menu { visibility: visible; opacity: 1; transform: translateY(0); }
.user-menu button { width: 100%; padding: 8px 10px; border: 0; border-radius: 4px; background: transparent; color: var(--text-secondary); text-align: left; cursor: pointer; }
.user-menu button[hidden] { display: none; }
.user-menu button:hover, .user-menu button:focus { background: var(--bg-tertiary); color: var(--text-primary); outline: none; }

/* ========== 按钮 ========== */
.btn {
  padding: 8px 16px;
  border: none;
  border-radius: 4px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-primary {
  background: var(--accent-primary);
  color: white;
}

.btn-primary:hover {
  background: var(--accent-secondary);
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--border-color);
}

.btn-small {
  padding: 4px 8px;
  font-size: 12px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  cursor: pointer;
}

.btn-small:hover {
  background: var(--border-color);
  color: var(--text-primary);
}

.select {
  padding: 6px 12px;
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  font-size: 14px;
  cursor: pointer;
}

/* ========== 题目列表 ========== */
.group-switcher {
  width: fit-content;
  margin: 16px 0 12px;
  padding: 4px;
  display: flex;
  gap: 4px;
  border: 1px solid var(--border-color);
  border-radius: 7px;
  background: var(--bg-secondary);
}
.group-toolbar { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.student-message-button { position: relative; width: 38px; height: 38px; display: grid; place-items: center; border: 1px solid var(--border-color); border-radius: 50%; background: var(--bg-secondary); color: var(--text-primary); font-size: 18px; cursor: pointer; }
.student-message-button:hover { border-color: var(--accent-primary); background: var(--bg-tertiary); }
.student-message-badge { position: absolute; top: -5px; right: -5px; min-width: 18px; height: 18px; padding: 0 4px; display: grid; place-items: center; border: 2px solid var(--bg-primary); border-radius: 99px; background: #e65353; color: white; font-size: 9px; font-weight: 700; }
.student-message-badge[hidden] { display: none; }
.student-message-modal[hidden] { display: none; }
.student-message-modal { position: fixed; inset: 0; z-index: 1250; padding: 24px; display: flex; align-items: flex-start; justify-content: center; overflow-y: auto; background: rgba(0,0,0,.68); backdrop-filter: blur(6px); }
.student-message-card { width: min(680px, 100%); margin-top: 6vh; overflow: hidden; border: 1px solid var(--border-color); border-radius: 10px; background: var(--bg-secondary); box-shadow: 0 24px 70px rgba(0,0,0,.5); }
.student-message-card > header { padding: 17px 19px; display: flex; align-items: center; justify-content: space-between; gap: 18px; border-bottom: 1px solid var(--border-color); }
.student-message-card > header h2 { font-size: 20px; }
.student-message-card > header p { margin-top: 3px; color: var(--text-secondary); font-size: 12px; }
.student-message-list { max-height: 68vh; padding: 14px; display: grid; gap: 10px; overflow-y: auto; }
.student-message-item { padding: 14px 15px; display: grid; gap: 8px; border: 1px solid var(--border-color); border-radius: 7px; background: var(--bg-primary); }
.student-message-item.unread { border-color: rgba(86,156,214,.55); }
.student-message-item header { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.student-message-item header strong { font-size: 14px; }
.student-message-item header span, .student-message-item footer { color: var(--text-secondary); font-size: 10px; }
.student-message-item p { color: var(--text-primary); font-size: 13px; line-height: 1.7; white-space: pre-wrap; overflow-wrap: anywhere; }
.student-message-item footer { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.student-alert-modal[hidden] { display: none; }
.student-alert-modal { position: fixed; inset: 0; z-index: 1300; padding: 24px; display: grid; place-items: center; background: rgba(0,0,0,.7); backdrop-filter: blur(7px); }
.student-alert-card { width: min(520px, 100%); padding: 22px; display: grid; gap: 17px; border: 1px solid var(--border-color); border-radius: 12px; background: var(--bg-secondary); box-shadow: 0 24px 70px rgba(0,0,0,.55); }
.student-alert-card header { display: grid; gap: 7px; }
.student-alert-card header span { color: var(--accent-primary); font-size: 11px; font-weight: 700; }
.student-alert-card h2 { font-size: 20px; line-height: 1.4; }
.student-alert-card > p { color: var(--text-primary); font-size: 14px; line-height: 1.8; white-space: pre-wrap; overflow-wrap: anywhere; }
.student-alert-card footer { padding-top: 14px; display: flex; align-items: center; justify-content: space-between; gap: 14px; border-top: 1px solid var(--border-color); }
.student-alert-card footer time { color: var(--text-secondary); font-size: 10px; }
.student-alert-card footer div { display: flex; gap: 9px; }

@media (max-width: 560px) {
  .student-alert-modal { padding: 14px; }
  .student-alert-card footer { align-items: stretch; flex-direction: column; }
  .student-alert-card footer div { justify-content: flex-end; }
}

.group-switch {
  min-width: 92px;
  padding: 7px 16px;
  border: 0;
  border-radius: 4px;
  background: transparent;
  color: var(--text-secondary);
  font: inherit;
  font-size: 14px;
  cursor: pointer;
}

.group-switch:hover { color: var(--text-primary); }
.group-switch.active { background: var(--accent-primary); color: white; }

.submission-heading { margin-top: 20px; display: flex; align-items: center; gap: 10px; }
.group-label {
  padding: 3px 9px;
  border: 1px solid rgba(86, 156, 214, .35);
  border-radius: 99px;
  background: rgba(14, 99, 156, .18);
  color: var(--info);
  font-size: 12px;
  font-weight: 500;
}

.problem-list {
  display: grid;
  gap: 12px;
  margin-top: 12px;
}

.problem-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 16px;
  cursor: pointer;
  transition: all 0.2s;
}

.problem-card:hover {
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

.problem-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.problem-id {
  color: var(--text-secondary);
  font-family: monospace;
  font-size: 14px;
}

.problem-title {
  font-size: 16px;
  font-weight: 500;
}
.resubmit-badge { margin-left: auto; padding: 3px 8px; border: 1px solid rgba(255,173,102,.45); border-radius: 999px; background: rgba(255,173,102,.09); color: var(--warning); font-size: 11px; white-space: nowrap; }

.difficulty {
  padding: 2px 8px;
  border-radius: 12px;
  font-size: 12px;
  font-weight: 500;
  margin-left: auto;
}

.difficulty.easy {
  background: rgba(78, 201, 176, 0.2);
  color: var(--success);
}

.difficulty.medium {
  background: rgba(220, 220, 170, 0.2);
  color: var(--warning);
}

.difficulty.hard {
  background: rgba(244, 135, 113, 0.2);
  color: var(--error);
}

.problem-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--text-secondary);
}

/* ========== 解题界面 ========== */
.solve-layout {
  display: grid;
  grid-template-columns: minmax(300px, var(--problem-pane-width, 1fr)) 20px minmax(380px, 1fr);
  gap: 0;
  margin-top: 16px;
  height: calc(100vh - 100px);
  height: calc(100dvh - 100px);
}

.solve-resizer {
  position: relative;
  cursor: col-resize;
  touch-action: none;
}

.solve-resizer::before {
  content: '';
  position: absolute;
  inset: 0 8px;
  border-radius: 2px;
  background: var(--border-color);
  transition: background .15s;
}

.solve-resizer:hover::before,
.solve-resizer:focus-visible::before,
.solve-layout.is-resizing .solve-resizer::before { background: var(--accent-primary); }
.solve-resizer:focus-visible { outline: none; }
.solve-layout.is-resizing { cursor: col-resize; user-select: none; }

.solve-resizer-grip {
  position: absolute;
  z-index: 1;
  top: 50%;
  left: 50%;
  width: 18px;
  min-height: 58px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  transform: translate(-50%, -50%);
  border: 1px solid var(--border-color);
  border-radius: 9px;
  background: var(--bg-secondary);
  box-shadow: 0 3px 10px rgba(0, 0, 0, .18);
  color: var(--text-secondary);
  font-size: 12px;
  line-height: 13px;
  transition: border-color .15s, background .15s, color .15s, box-shadow .15s;
}

.solve-resizer-grip span:nth-child(2) { font-size: 13px; }
.solve-resizer:hover .solve-resizer-grip,
.solve-resizer:focus-visible .solve-resizer-grip,
.solve-layout.is-resizing .solve-resizer-grip {
  border-color: var(--accent-primary);
  background: var(--bg-tertiary);
  box-shadow: 0 3px 12px rgba(76, 141, 255, .3);
  color: var(--accent-primary);
}

.problem-panel {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 20px;
  overflow-y: auto;
}

.problem-panel h2 {
  font-size: 20px;
  margin-bottom: 16px;
  color: var(--accent-secondary);
}

.problem-content h3 {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  margin: 16px 0 8px 0;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.problem-content h1,
.problem-content h2,
.problem-content h3,
.problem-content h4 {
  margin: 18px 0 9px;
  color: var(--text-primary);
  line-height: 1.35;
  text-transform: none;
  letter-spacing: normal;
}

.problem-content h1 { font-size: 21px; }
.problem-content h2 { padding-bottom: 6px; border-bottom: 1px solid var(--border-color); font-size: 18px; }
.problem-content h3 { font-size: 15px; }
.problem-content h4 { font-size: 14px; }
.problem-content > .problem-section-title {
  margin: 22px 0 10px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 16px;
  font-weight: 700;
}
.problem-content > .problem-section-title:first-child { margin-top: 8px; }
.problem-section-title[hidden] { display: none; }
.collapsible-section-title { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.section-toggle {
  padding: 3px 9px;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  font: inherit;
  font-size: 12px;
  font-weight: 400;
  cursor: pointer;
}
.section-toggle:hover { border-color: var(--accent-primary); color: var(--text-primary); }
.problem-content p { margin: 8px 0; line-height: 1.75; }
.problem-content ul,
.problem-content ol { margin: 9px 0; padding-left: 24px; line-height: 1.75; }
.problem-content li + li { margin-top: 3px; }
.problem-content blockquote { margin: 12px 0; padding: 9px 13px; border-left: 3px solid var(--accent-primary); background: var(--bg-tertiary); color: var(--text-secondary); }
.problem-content blockquote p { margin: 0; }
.problem-content a { color: var(--accent-secondary); text-underline-offset: 3px; }
.problem-content hr { margin: 18px 0; border: 0; border-top: 1px solid var(--border-color); }
.problem-content code:not(pre code) { padding: 2px 5px; border-radius: 4px; background: var(--bg-tertiary); color: #f0b4c6; font-family: 'Consolas', 'Monaco', monospace; font-size: .9em; }

.problem-content pre {
  background: var(--bg-tertiary);
  padding: 12px;
  border-radius: 4px;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 13px;
  overflow-x: auto;
}

.problem-content pre code { padding: 0; background: transparent; font-family: 'Consolas', 'Monaco', monospace; line-height: 1.6; }
.problem-content table { width: 100%; margin: 12px 0; border-collapse: collapse; font-size: 13px; }
.problem-content th,
.problem-content td { padding: 8px 10px; border: 1px solid var(--border-color); text-align: left; }
.problem-content th { background: var(--bg-tertiary); font-weight: 600; }
.problem-content tbody tr:nth-child(even) { background: rgba(255,255,255,.018); }
.problem-content .katex-display { max-width: 100%; margin: 14px 0; overflow-x: auto; overflow-y: hidden; }

.problem-content .problem-image {
  display: block;
  max-width: 100%;
  max-height: 520px;
  margin: 14px auto;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: #e2e5ea;
  box-sizing: border-box;
  object-fit: contain;
}

.problem-samples { display: grid; gap: 14px; }
.sample-group { display: grid; gap: 12px; }
.sample {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.editor-panel {
  --io-panel-height: 108px;
  --result-peek-height: 0px;
  min-height: 0;
}

.editor-workspace {
  height: calc(100% - var(--result-peek-height));
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  align-items: center;
  margin-bottom: 6px;
}

.toolbar .select { padding-block: 4px; }
.toolbar .btn { padding-block: 6px; }
.toolbar .btn-small { padding-block: 3px; }

.font-size-control {
  display: flex;
  align-items: center;
  gap: 5px;
  margin-right: auto;
  color: var(--text-secondary);
  font-size: 12px;
  white-space: nowrap;
}

.font-size-control .btn-small { min-width: 31px; }
.font-size-label { color: var(--text-secondary); }

.sample-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 4px;
}

.editor {
  flex: 1;
  min-height: 280px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  overflow: hidden;
}

.io-resizer {
  position: relative;
  height: 24px;
  flex: 0 0 24px;
  margin-top: 2px;
  cursor: row-resize;
  touch-action: none;
  user-select: none;
}

.io-resizer::before {
  content: '';
  position: absolute;
  top: 11px;
  right: 0;
  left: 0;
  height: 2px;
  border-radius: 2px;
  background: var(--border-color);
  transition: background .15s;
}

.io-resizer:hover::before,
.io-resizer:focus-visible::before,
.editor-panel.is-io-resizing .io-resizer::before { background: var(--accent-primary); }
.io-resizer:focus-visible { outline: none; }
.editor-panel.is-io-resizing { cursor: row-resize; user-select: none; }

.io-resizer-grip {
  position: absolute;
  z-index: 1;
  top: 50%;
  left: 50%;
  min-width: 72px;
  height: 20px;
  padding: 0 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  transform: translate(-50%, -50%);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: var(--bg-secondary);
  box-shadow: 0 2px 7px rgba(0, 0, 0, .18);
  color: var(--text-secondary);
  font-size: 12px;
  line-height: 1;
  transition: border-color .15s, background .15s, color .15s, box-shadow .15s;
}

.io-resizer-grip span:nth-child(2) { font-size: 14px; }
.io-resizer:hover .io-resizer-grip,
.io-resizer:focus-visible .io-resizer-grip,
.editor-panel.is-io-resizing .io-resizer-grip {
  border-color: var(--accent-primary);
  background: var(--bg-tertiary);
  box-shadow: 0 2px 9px rgba(76, 141, 255, .28);
  color: var(--accent-primary);
}

.io-toggle-btn {
  position: absolute;
  z-index: 2;
  top: 50%;
  right: 0;
  padding: 2px 8px;
  transform: translateY(-50%);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font: inherit;
  font-size: 11px;
  cursor: pointer;
}
.io-toggle-btn:hover,
.io-toggle-btn:focus-visible { border-color: var(--accent-primary); color: var(--text-primary); outline: none; }

.io-panel {
  height: var(--io-panel-height);
  min-height: 0;
  flex: 0 0 var(--io-panel-height);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  overflow: hidden;
}

.editor-panel.io-collapsed .io-panel { display: none; }

.io-section {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-height: 0;
}

.io-section label {
  font-size: 12px;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.io-textarea {
  flex: 1;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 8px;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 13px;
  resize: none;
  min-height: 0;
}

.io-output {
  flex: 1;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 8px;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 13px;
  min-height: 0;
  max-height: none;
  overflow: auto;
  white-space: pre-wrap;
}

.result-panel {
  margin-top: 0;
}

.result-panel:has(#judge-result:not(:empty), #judge-detail:not(:empty)) { padding-top: 12px; }

.judge-result-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.result-toggle-btn {
  flex: 0 0 auto;
  padding: 3px 9px;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font: inherit;
  font-size: 11px;
  cursor: pointer;
}
.result-toggle-btn:hover,
.result-toggle-btn:focus-visible { border-color: var(--accent-primary); color: var(--text-primary); outline: none; }
.result-toggle-btn[hidden],
.judge-detail[hidden] { display: none; }

.judge-detail {
  margin-top: 0;
  display: grid;
  gap: 8px;
}

.judge-detail:not(:empty) { margin-top: 12px; }

.test-case {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 12px;
}

.test-case.passed {
  border-left: 3px solid var(--success);
}

.test-case.failed {
  border-left: 3px solid var(--error);
}

.tc-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 8px;
  font-size: 13px;
  font-weight: 500;
}

.tc-detail {
  display: grid;
  gap: 8px;
  font-size: 12px;
}

.tc-detail pre {
  background: var(--bg-tertiary);
  padding: 6px;
  border-radius: 3px;
  font-family: 'Consolas', 'Monaco', monospace;
  font-size: 12px;
  overflow-x: auto;
  white-space: pre-wrap;
}

/* ========== 排名表格 ========== */
.ranking-selector {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 16px;
}

.ranking-selector label {
  color: var(--text-secondary);
  font-size: 14px;
}

.ranking-selector .select {
  min-width: 240px;
}

.ranking {
  width: 100%;
  border-collapse: collapse;
  margin-top: 20px;
}

.ranking th {
  background: var(--bg-tertiary);
  padding: 12px;
  text-align: left;
  font-weight: 600;
  font-size: 14px;
  border-bottom: 2px solid var(--border-color);
}

.ranking td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border-color);
  font-size: 14px;
}

.ranking tr:hover {
  background: var(--bg-tertiary);
}

/* ========== 状态提示 ========== */
.success {
  color: var(--success);
}

.error {
  color: var(--error);
}

.warning {
  color: var(--warning);
}

.info {
  color: var(--info);
}
.timing-banner { margin: 0 0 12px; padding: 11px 14px; border: 1px solid var(--border-color); border-left: 3px solid var(--info); border-radius: 6px; background: var(--bg-secondary); color: var(--text-primary); font-size: 13px; }
.timing-banner.active { border-left-color: var(--success); }
.timing-banner.warning { border-left-color: var(--warning); }
.timing-banner.closed { border-left-color: var(--error); }

/* ========== 套卷模式 ========== */
.exam-list { margin-top: 16px; display: grid; gap: 12px; }
.exam-card { width: 100%; padding: 17px 18px; display: grid; gap: 9px; border: 1px solid var(--border-color); border-radius: 7px; background: var(--bg-secondary); color: var(--text-primary); text-align: left; cursor: pointer; transition: border-color .18s, transform .18s; }
.exam-card:hover { border-color: var(--accent-primary); transform: translateY(-1px); }
.exam-card.is-locked { opacity: .72; cursor: not-allowed; }
.exam-card.is-locked:hover { border-color: var(--border-color); transform: none; }
.exam-card-lock { margin-left: auto; padding: 3px 7px; border: 1px solid var(--border-color); border-radius: 999px; color: var(--warning); font-size: 11px; }
.exam-card > div { display: flex; align-items: center; gap: 12px; }
.exam-card > div strong { font-size: 16px; }
.exam-card > p { color: var(--text-secondary); font-size: 13px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.exam-card footer { display: flex; align-items: center; gap: 15px; color: var(--text-secondary); font-size: 12px; }
.exam-card footer b { margin-left: auto; color: var(--success); font-size: 14px; }
.exam-card-statuses { margin-left: auto; display: flex; align-items: center; gap: 7px; }
.exam-status-pill { padding: 2px 8px; border: 1px solid var(--border-color); border-radius: 999px; white-space: nowrap; }
.exam-status-pill.timing.active, .exam-status-pill.submission.submitted { border-color: rgba(78,201,176,.45); color: var(--success); }
.exam-status-pill.timing.paused, .exam-status-pill.timing.upcoming, .exam-status-pill.submission.pending { color: var(--warning); }
.exam-status-pill.timing.ended { color: var(--text-secondary); }
.exam-page-heading { margin: 20px 0 14px; display: flex; align-items: center; gap: 15px; }
.exam-page-actions { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; }
.exam-docx-import { position: relative; cursor: pointer; }
.exam-docx-import input { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }
.exam-answer-sheet-status { min-height: 0; margin: -7px 0 12px; color: var(--text-secondary); font-size: 12px; }
.exam-answer-sheet-status:empty { display: none; }
.exam-page-heading h2 { font-size: 22px; }
.exam-page-heading p { color: var(--text-secondary); font-size: 12px; }
.exam-description { margin-bottom: 16px; padding: 16px 18px; border: 1px solid var(--border-color); border-radius: 7px; background: var(--bg-secondary); }
.exam-description:empty { display: none; }
.student-exam-form { display: grid; gap: 18px; }
.student-exam-question { overflow: hidden; border: 1px solid var(--border-color); border-radius: 8px; background: var(--bg-secondary); }
.student-exam-question > header { padding: 15px 18px; display: flex; align-items: center; justify-content: space-between; gap: 14px; border-bottom: 1px solid var(--border-color); background: rgba(255,255,255,.018); }
.student-exam-question > header div { display: flex; align-items: baseline; gap: 10px; }
.student-exam-question > header span { color: var(--text-secondary); font-size: 12px; }
.student-exam-question > header h3 { font-size: 16px; }
.student-exam-question > header > strong { color: var(--accent-secondary); white-space: nowrap; }
.exam-rule-warning { margin: 13px 18px 0; padding: 9px 11px; border-left: 3px solid var(--warning); background: rgba(220,220,170,.06); color: var(--warning); font-size: 12px; }
.exam-question-description { padding: 14px 18px 0; }
.student-exam-parts { display: grid; }
.student-exam-part { padding: 17px 18px; display: grid; gap: 11px; border-top: 1px solid var(--border-color); }
.student-exam-part:first-child { border-top: 0; }
.exam-part-label { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.exam-part-label > span { color: var(--text-secondary); font-size: 11px; }
.exam-part-prompt { min-width: 0; }
.exam-options { display: grid; gap: 8px; }
.exam-options label { padding: 9px 11px; display: flex; align-items: flex-start; gap: 9px; border: 1px solid var(--border-color); border-radius: 5px; cursor: pointer; }
.exam-options label:hover { background: var(--bg-tertiary); }
.exam-options input { margin-top: 5px; accent-color: var(--accent-primary); }
.exam-text-answer { width: 100%; min-height: 42px; padding: 10px; border: 1px solid var(--border-color); border-radius: 5px; outline: none; resize: vertical; background: var(--bg-primary); color: var(--text-primary); font: inherit; }
.exam-text-answer:focus { border-color: var(--accent-primary); }
.exam-programming { display: grid; gap: 8px; }
.exam-programming > div { display: flex; align-items: center; justify-content: space-between; gap: 10px; color: var(--text-secondary); font-size: 12px; }
.exam-programming select { padding: 6px 9px; border: 1px solid var(--border-color); border-radius: 4px; background: var(--bg-tertiary); color: var(--text-primary); }
.exam-programming textarea { width: 100%; padding: 12px; border: 1px solid var(--border-color); border-radius: 6px; outline: none; resize: vertical; background: #181818; color: var(--text-primary); font: 13px/1.6 Consolas, Monaco, monospace; tab-size: 4; }
.exam-programming textarea:focus { border-color: var(--accent-primary); }
.exam-programming-link-card { padding: 13px 14px; display: flex; align-items: center; justify-content: space-between; gap: 16px; border: 1px solid var(--border-color); border-radius: 7px; background: var(--bg-primary); }
.exam-programming-link-card > div { min-width: 0; display: grid; gap: 4px; }
.exam-programming-link-card span, .exam-programming-link-card small { color: var(--text-secondary); font-size: 11px; }
.exam-programming-link-card strong { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.exam-programming-link-card small { color: var(--success); }
.exam-problem-context { margin: 16px 0 10px; padding: 11px 14px; display: flex; align-items: center; justify-content: space-between; gap: 15px; border: 1px solid var(--accent-primary); border-radius: 7px; background: rgba(79,128,255,.08); }
.exam-problem-context[hidden] { display: none; }
.exam-problem-context > div { min-width: 0; display: grid; gap: 3px; }
.exam-problem-context span { overflow: hidden; color: var(--text-secondary); font-size: 12px; text-overflow: ellipsis; white-space: nowrap; }
.exam-submit-bar { position: sticky; bottom: 0; z-index: 20; margin-top: 18px; padding: 12px 15px; display: flex; align-items: center; justify-content: flex-end; gap: 14px; border: 1px solid var(--border-color); border-radius: 7px 7px 0 0; background: rgba(37,37,38,.96); backdrop-filter: blur(8px); }
.exam-submit-bar span { margin-right: auto; color: var(--text-secondary); font-size: 12px; }
.exam-result { margin: 16px 0 30px; }
.exam-result:empty { display: none; }
.exam-result-card { padding: 18px; border: 1px solid var(--border-color); border-radius: 7px; background: var(--bg-secondary); }
.exam-result-card > p { margin-top: 7px; color: var(--text-secondary); }
.exam-result-parts { margin-top: 13px; display: grid; gap: 7px; }
.exam-result-parts > div { padding: 9px 11px; display: grid; grid-template-columns: 1fr auto auto; gap: 14px; border-radius: 5px; background: var(--bg-tertiary); font-size: 12px; }
.exam-result-parts p { grid-column: 1 / -1; color: var(--text-secondary); }

.admin-impersonation-banner {
  position: sticky;
  top: 0;
  z-index: 1100;
  min-height: 38px;
  padding: 7px 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  color: #fff4d6;
  background: #6b3d08;
  border-bottom: 1px solid #b8731d;
  font-size: 13px;
}
.admin-impersonation-banner[hidden] { display: none; }
.admin-impersonation-banner button {
  padding: 4px 10px;
  color: #fff;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid rgba(255, 255, 255, 0.38);
  border-radius: 5px;
  cursor: pointer;
}
.admin-impersonation-banner button:hover { background: rgba(255, 255, 255, 0.2); }

/* ========== 响应式 ========== */
@media (max-width: 1024px) {
  .solve-layout {
    grid-template-columns: 1fr;
    height: auto;
  }

  .solve-resizer { display: none; }

  .editor-workspace { height: auto; min-height: 620px; }

  .problem-panel {
    max-height: 400px;
  }

  .sample {
    grid-template-columns: 1fr;
  }

  .exam-page-heading { align-items: flex-start; flex-direction: column; }
  .exam-programming-link-card, .exam-problem-context { align-items: stretch; flex-direction: column; }
  .exam-submit-bar { align-items: stretch; flex-direction: column; }
  .exam-submit-bar span { margin-right: 0; }
}