/* ==========================================================================
   学而思希望学课程资料分类检索与申请系统 - 样式表 (Modern Design System)
   ========================================================================== */

:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --secondary: #0ea5e9;
  --success: #10b981;
  --success-light: #ecfdf5;
  --warning: #f59e0b;
  --danger: #ef4444;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --bg-page: #f8fafc;
  --bg-card: #ffffff;
  --border: #e2e8f0;
  --border-focus: #3b82f6;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  padding-bottom: 90px;
}

/* 顶部导航与横幅 */
.site-header {
  background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 50%, #0284c7 100%);
  color: #ffffff;
  padding: 36px 20px 48px;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

.site-header::after {
  content: "";
  position: absolute;
  top: -40%;
  right: -10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255,255,255,0.15) 0%, rgba(255,255,255,0) 70%);
  pointer-events: none;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.brand-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, 0.18);
  backdrop-filter: blur(8px);
  padding: 4px 12px;
  border-radius: var(--radius-full);
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 12px;
  border: 1px solid rgba(255, 255, 255, 0.25);
}

.site-title {
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 8px;
}

.site-subtitle {
  font-size: 15px;
  color: rgba(255, 255, 255, 0.85);
  max-width: 720px;
}

/* 主容器 */
.main-container {
  max-width: 1200px;
  margin: -24px auto 0;
  padding: 0 16px;
  position: relative;
  z-index: 10;
}

/* 控制岛与筛选面板 */
.filter-panel {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
  margin-bottom: 24px;
}

.search-bar-wrap {
  display: flex;
  gap: 12px;
  margin-bottom: 20px;
}

.search-input-box {
  flex: 1;
  position: relative;
  display: flex;
  align-items: center;
}

.search-input-box svg {
  position: absolute;
  left: 14px;
  width: 18px;
  height: 18px;
  color: var(--text-light);
}

.search-input {
  width: 100%;
  padding: 12px 14px 12px 42px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 15px;
  background: #f8fafc;
  transition: var(--transition);
}

.search-input:focus {
  outline: none;
  background: #ffffff;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.btn-clear-filter {
  padding: 0 16px;
  background: #f1f5f9;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-size: 14px;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-clear-filter:hover {
  background: #e2e8f0;
  color: var(--text-main);
}

/* 学段切换 Tabs */
.stage-tabs {
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 14px;
  margin-bottom: 16px;
  overflow-x: auto;
  scrollbar-width: none;
}

.stage-tabs::-webkit-scrollbar {
  display: none;
}

.tab-btn {
  background: none;
  border: none;
  padding: 8px 18px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}

.tab-btn:hover {
  background: #f1f5f9;
  color: var(--text-main);
}

.tab-btn.active {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.35);
}

/* 学科选择 Pills */
.subject-pills-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.filter-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  white-space: nowrap;
}

.subject-pills {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.pill-btn {
  background: #f8fafc;
  border: 1px solid var(--border);
  padding: 5px 12px;
  font-size: 13px;
  border-radius: var(--radius-full);
  color: var(--text-main);
  cursor: pointer;
  transition: var(--transition);
}

.pill-btn:hover {
  background: #e2e8f0;
}

.pill-btn.active {
  background: #eff6ff;
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 600;
}

/* 下拉选择器行 */
.dropdown-filter-row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.select-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.select-control {
  padding: 6px 12px;
  font-size: 13px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: #ffffff;
  color: var(--text-main);
  cursor: pointer;
}

.select-control:focus {
  outline: none;
  border-color: var(--border-focus);
}

/* 课程统计与展示 */
.results-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.results-count {
  font-size: 14px;
  color: var(--text-muted);
}

.results-count b {
  color: var(--primary);
}

/* 课程卡片网格 */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}

.course-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 16px;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: var(--transition);
  position: relative;
}

.course-card:hover {
  border-color: #cbd5e1;
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.course-card.selected {
  border-color: var(--primary);
  background: #fcfdff;
  box-shadow: 0 0 0 1px var(--primary);
}

.card-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 10px;
}

.tag {
  font-size: 11px;
  padding: 2px 7px;
  border-radius: 4px;
  font-weight: 500;
}

.tag-stage {
  background: #f1f5f9;
  color: #475569;
}

.tag-subject {
  background: #eff6ff;
  color: #1d4ed8;
}

.tag-semester {
  background: #fef3c7;
  color: #92400e;
}

.tag-type {
  background: #f3e8ff;
  color: #6b21a8;
}

.course-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-main);
  line-height: 1.4;
  margin-bottom: 12px;
  word-break: break-word;
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 10px;
  border-top: 1px dashed var(--border);
  margin-top: 6px;
}

.teacher-info {
  display: flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  color: var(--text-muted);
}

.btn-select-course {
  border: none;
  background: var(--primary-light);
  color: var(--primary);
  font-size: 12px;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.btn-select-course:hover {
  background: #dbeafe;
}

.course-card.selected .btn-select-course {
  background: var(--success);
  color: #ffffff;
}

/* 底部常驻申请条 (Sticky Floating Bar) */
.floating-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--border);
  padding: 12px 20px;
  box-shadow: 0 -4px 12px rgba(0, 0, 0, 0.06);
  z-index: 100;
  display: flex;
  justify-content: center;
}

.floating-bar-inner {
  max-width: 1200px;
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.selected-summary {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
}

.badge-count {
  background: var(--primary);
  color: #ffffff;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-weight: 700;
  font-size: 13px;
}

.btn-clear-selected {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  cursor: pointer;
  transition: var(--transition);
}

.btn-clear-selected:hover {
  color: var(--danger);
  border-color: var(--danger);
  background: #fef2f2;
}

.btn-copy-serial {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid rgba(37, 99, 235, 0.2);
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  cursor: pointer;
  margin-left: 8px;
  transition: var(--transition);
}

.btn-copy-serial:hover {
  background: var(--primary);
  color: #ffffff;
}

.btn-open-form {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #ffffff;
  border: none;
  padding: 10px 24px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.35);
  transition: var(--transition);
}

.btn-open-form:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.45);
}

.btn-open-form:disabled {
  background: #cbd5e1;
  box-shadow: none;
  cursor: not-allowed;
  transform: none;
}

/* 模态抽屉 / 弹窗 (Modal Drawer) */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(4px);
  z-index: 200;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-xl);
  transform: scale(0.95);
  transition: transform 0.25s ease;
  overflow: hidden;
}

.modal-backdrop.open .modal-card {
  transform: scale(1);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 24px;
  border-bottom: 1px solid var(--border);
}

.modal-title {
  font-size: 18px;
  font-weight: 700;
}

.btn-close-modal {
  background: none;
  border: none;
  font-size: 24px;
  line-height: 1;
  color: var(--text-muted);
  cursor: pointer;
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
}

/* 已选课程小列表 */
.selected-list-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 12px;
  margin-bottom: 20px;
  max-height: 160px;
  overflow-y: auto;
}

.selected-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 8px;
  border-bottom: 1px dashed var(--border);
  font-size: 13px;
}

.selected-item:last-child {
  border-bottom: none;
}

.btn-remove-item {
  background: none;
  border: none;
  color: var(--danger);
  cursor: pointer;
  font-size: 16px;
  padding: 0 4px;
}

/* 表单输入组 */
.form-group {
  margin-bottom: 16px;
}

.form-label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
}

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

.form-input {
  width: 100%;
  padding: 10px 14px;
  font-size: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: #ffffff;
  transition: var(--transition);
}

.form-input:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.form-textarea {
  width: 100%;
  padding: 10px 14px;
  font-size: 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  min-height: 70px;
  resize: vertical;
}

.form-textarea:focus {
  outline: none;
  border-color: var(--border-focus);
}

.form-tip {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 4px;
}

.modal-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  background: #f8fafc;
}

.btn-cancel {
  padding: 10px 18px;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 14px;
  cursor: pointer;
}

.btn-submit {
  padding: 10px 24px;
  background: var(--primary);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
}

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

.btn-submit:disabled {
  background: #94a3b8;
  cursor: not-allowed;
}

/* 提交成功状态 */
.success-screen {
  text-align: center;
  padding: 30px 10px;
}

.success-icon {
  width: 64px;
  height: 64px;
  background: var(--success-light);
  color: var(--success);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.success-title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: 8px;
}

.success-desc {
  font-size: 14px;
  color: var(--text-muted);
  margin-bottom: 20px;
}

.receipt-box {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 14px;
  text-align: left;
  font-size: 13px;
  margin-bottom: 24px;
}

.receipt-row {
  display: flex;
  justify-content: space-between;
  padding: 4px 0;
}

.empty-tip {
  grid-column: 1 / -1;
  text-align: center;
  padding: 48px 0;
  color: var(--text-muted);
  font-size: 15px;
}

@media (max-width: 640px) {
  .site-title { font-size: 22px; }
  .filter-panel { padding: 16px; }
  .search-bar-wrap { flex-direction: column; }
  .course-grid { grid-template-columns: 1fr; }
  .floating-bar-inner { flex-direction: row; }
}