/* ============================================
   question.css — 教程中心页面专属样式
   依赖 common.css（已提供 reset、变量、导航、按钮、共用布局等）
   ============================================ */

/* === HERO === */
.hero {
  padding: 76px 0 64px;
  background:
    radial-gradient(circle at 16% 12%, rgba(37, 99, 235, 0.1), transparent 30%),
    radial-gradient(circle at 86% 14%, rgba(124, 58, 237, 0.08), transparent 28%),
    linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
  border-bottom: 1px solid var(--line);
}

.hero-grid {
  display: grid;
  grid-template-columns: 0.95fr 1.05fr;
  gap: 44px;
  align-items: center;
}

.hero-actions {
  margin-bottom: 28px;
}

.hero h1 {
  max-width: 680px;
  font-size: clamp(42px, 5.6vw, 72px);
  line-height: 1.03;
  letter-spacing: -3.2px;
  font-weight: 850;
  margin-bottom: 24px;
}

.hero p {
  max-width: 650px;
  color: var(--muted);
  font-size: 18px;
  margin-bottom: 28px;
}

.hero p strong {
  color: var(--text);
  font-weight: 750;
}

/* === GUIDE CARD === */
.guide-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 28px;
  box-shadow: var(--shadow);
  padding: 24px;
  position: relative;
  overflow: hidden;
}

.guide-main {
  position: relative;
  z-index: 2;
  border-radius: 24px;
  background: linear-gradient(135deg, #0f172a 0%, #172554 56%, #1e1b4b 100%);
  color: #fff;
  padding: 28px;
  margin-bottom: 16px;
  overflow: hidden;
}

.guide-main::after {
  content: "";
  position: absolute;
  right: -60px;
  top: -60px;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: rgba(191, 219, 254, 0.18);
}

.guide-icon {
  position: relative;
  z-index: 2;
  width: 64px;
  height: 64px;
  border-radius: 20px;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.14);
  color: #bfdbfe;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 34px;
  margin-bottom: 22px;
}

.guide-main span {
  position: relative;
  z-index: 2;
  display: block;
  color: #bfdbfe;
  font-size: 13px;
  font-weight: 850;
  margin-bottom: 8px;
}

.guide-main h2 {
  position: relative;
  z-index: 2;
  font-size: 30px;
  line-height: 1.16;
  letter-spacing: -1px;
  margin-bottom: 10px;
}

.guide-main p {
  position: relative;
  z-index: 2;
  color: #cbd5e1;
  font-size: 14px;
  margin: 0;
}

.guide-stats {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.guide-stat {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 16px;
  box-shadow: var(--shadow-soft);
}

.guide-stat span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 850;
  margin-bottom: 6px;
}

.guide-stat strong {
  display: block;
  color: var(--text);
  font-size: 20px;
  line-height: 1;
  letter-spacing: -0.5px;
}

/* === SEARCH BOX === */
.search-box-wrap {
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.search-box {
  flex: 1;
  position: relative;
}

.search-box > i {
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  font-size: 18px;
}

.search-box input {
  width: 100%;
  height: 48px;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 0 46px;
  background: #fff;
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: 0.18s ease;
  box-shadow: var(--shadow-soft);
}

.search-box input:focus {
  border-color: #bfdbfe;
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.08);
}

.search-clear {
  position: absolute;
  right: 10px;
  top: 50%;
  transform: translateY(-50%);
  width: 30px;
  height: 30px;
  border: 0;
  border-radius: 10px;
  background: var(--bg-soft);
  color: var(--muted);
  cursor: pointer;
  display: none;
  align-items: center;
  justify-content: center;
}

.search-clear.show {
  display: inline-flex;
}

.search-result-tip {
  margin-bottom: 14px;
  padding: 10px 13px;
  border-radius: 14px;
  background: var(--primary-soft);
  color: var(--primary);
  font-size: 13px;
  font-weight: 750;
  display: none;
}

.search-result-tip.show {
  display: block;
}

/* === TABS === */
.tabs-shell {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 28px;
  box-shadow: var(--shadow);
  overflow: hidden;
}

.tabs-nav {
  padding: 12px;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.tab-btn {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 16px;
  padding: 14px;
  cursor: pointer;
  font-family: inherit;
  text-align: left;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: 0.18s ease;
}

.tab-btn:hover {
  transform: translateY(-2px);
  border-color: var(--line-dark);
}

.tab-btn.active {
  border-color: #bfdbfe;
  background: var(--primary-soft);
  box-shadow: 0 12px 30px rgba(37, 99, 235, 0.08);
}

.tab-icon {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  font-size: 22px;
}

.tab-btn[data-tab="app"] .tab-icon {
  background: var(--primary-soft);
  color: var(--primary);
}

.tab-btn[data-tab="file"] .tab-icon {
  background: var(--cyan-soft);
  color: var(--cyan);
}

.tab-btn[data-tab="sign"] .tab-icon {
  background: var(--purple-soft);
  color: var(--purple);
}

.tab-btn strong {
  display: block;
  color: var(--text);
  font-size: 16px;
  line-height: 1.2;
  margin-bottom: 3px;
}

.tab-btn span span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.tab-panel {
  display: none;
  padding: 22px;
}

.tab-panel.active {
  display: block;
}

/* === PANEL HEAD === */
.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 18px;
  margin-bottom: 18px;
}

.panel-head h2 {
  font-size: 30px;
  line-height: 1.15;
  letter-spacing: -1px;
  margin-bottom: 6px;
}

.panel-head p {
  color: var(--muted);
  font-size: 14px;
  max-width: 680px;
}

.panel-tag {
  padding: 7px 11px;
  border-radius: 999px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
  font-weight: 850;
  white-space: nowrap;
}

/* === QUICK FLOW === */
.quick-flow {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-bottom: 18px;
}

.flow-card {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 16px;
  padding: 14px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-soft);
}

.flow-card::after {
  content: attr(data-step);
  position: absolute;
  right: 12px;
  top: 8px;
  font-size: 30px;
  font-weight: 900;
  color: #e2e8f0;
  line-height: 1;
}

.flow-card i {
  position: relative;
  z-index: 2;
  width: 32px;
  height: 32px;
  border-radius: 11px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 17px;
  margin-bottom: 9px;
}

.flow-card strong {
  position: relative;
  z-index: 2;
  display: block;
  font-size: 14px;
  margin-bottom: 4px;
}

.flow-card span {
  position: relative;
  z-index: 2;
  display: block;
  color: var(--muted);
  font-size: 12.5px;
  line-height: 1.5;
}

/* === QA CARDS === */
.qa-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.qa-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  box-shadow: var(--shadow-soft);
  transition: 0.18s ease;
  min-height: 148px;
  cursor: pointer;
}

.qa-card.hide {
  display: none;
}

.qa-card:hover {
  transform: translateY(-2px);
  border-color: var(--line-dark);
  box-shadow: 0 10px 22px rgba(15, 23, 42, 0.06);
}

.qa-card:focus {
  outline: 3px solid rgba(37, 99, 235, 0.18);
  outline-offset: 2px;
}

.qa-card h3 {
  font-size: 14.5px;
  line-height: 1.32;
  letter-spacing: -0.2px;
  margin-bottom: 7px;
  display: flex;
  gap: 7px;
  align-items: flex-start;
}

.qa-card h3 i {
  color: var(--primary);
  font-size: 16px;
  margin-top: 2px;
  flex: 0 0 auto;
}

.qa-card p {
  color: var(--muted);
  font-size: 12.8px;
  line-height: 1.58;
  margin-bottom: 6px;
}

.qa-card p:last-child {
  margin-bottom: 0;
}

.qa-card ul {
  display: grid;
  gap: 4px;
  margin-top: 6px;
}

.qa-card li {
  position: relative;
  padding-left: 14px;
  color: var(--muted);
  font-size: 12.5px;
  line-height: 1.55;
}

.qa-card li::before {
  content: "";
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--primary);
  position: absolute;
  left: 2px;
  top: 8px;
}

.qa-card mark {
  background: #fef3c7;
  color: #92400e;
  padding: 0 2px;
  border-radius: 4px;
}

/* === NOTICE CARDS === */
.notice-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.notice-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 22px;
  box-shadow: var(--shadow-soft);
}

.notice-card i {
  width: 42px;
  height: 42px;
  border-radius: 13px;
  background: var(--orange-soft);
  color: var(--orange);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  margin-bottom: 14px;
}

.notice-card h3 {
  font-size: 18px;
  letter-spacing: -0.4px;
  margin-bottom: 8px;
}

.notice-card p {
  color: var(--muted);
  font-size: 14px;
}

/* === QA MODAL === */
.qa-modal-mask {
  position: fixed;
  inset: 0;
  z-index: 999;
  background: rgba(15, 23, 42, 0.46);
  backdrop-filter: blur(10px);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 22px;
}

.qa-modal-mask.show {
  display: flex;
}

.qa-modal {
  width: min(620px, 100%);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: 0 28px 80px rgba(15, 23, 42, 0.22);
  overflow: hidden;
  animation: modalIn 0.18s ease;
}

@keyframes modalIn {
  from {
    opacity: 0;
    transform: translateY(12px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.qa-modal-head {
  padding: 20px 22px;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(circle at 12% 8%, rgba(37, 99, 235, 0.08), transparent 30%),
    var(--bg-soft);
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.qa-modal-title-wrap {
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.qa-modal-icon {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  background: var(--primary-soft);
  color: var(--primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 auto;
  font-size: 22px;
}

.qa-modal-head h3 {
  font-size: 20px;
  line-height: 1.35;
  letter-spacing: -0.5px;
  margin: 0;
}

.qa-modal-close {
  width: 36px;
  height: 36px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--muted);
  border-radius: 12px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  transition: 0.18s ease;
  flex: 0 0 auto;
}

.qa-modal-close:hover {
  color: var(--text);
  border-color: var(--line-dark);
  transform: translateY(-1px);
}

.qa-modal-body {
  padding: 22px;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1.8;
}

.qa-modal-body p {
  margin-bottom: 10px;
  color: var(--text-soft);
}

.qa-modal-body p:last-child {
  margin-bottom: 0;
}

.qa-modal-body ul {
  display: grid;
  gap: 8px;
  margin-top: 10px;
}

.qa-modal-body li {
  position: relative;
  padding-left: 18px;
  color: var(--muted);
}

.qa-modal-body li::before {
  content: "";
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--primary);
  position: absolute;
  left: 3px;
  top: 12px;
}

.qa-modal-foot {
  padding: 14px 22px 20px;
  display: flex;
  justify-content: flex-end;
}

.qa-modal-foot .btn {
  width: auto;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 1180px) {
  .qa-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 1060px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .tabs-nav,
  .quick-flow,
  .notice-grid {
    grid-template-columns: 1fr;
  }

  .tab-btn {
    padding: 15px;
  }

  .panel-head {
    flex-direction: column;
  }

  .panel-tag {
    align-self: flex-start;
  }
}

@media (max-width: 720px) {
  .hero {
    padding: 56px 0 48px;
  }

  .hero h1 {
    letter-spacing: -1.5px;
  }

  .section-title {
    letter-spacing: -1.5px;
  }

  .hero p {
    font-size: 16px;
  }

  .section-desc {
    font-size: 16px;
  }

  .hero-actions {
    align-items: stretch;
  }

  .search-box-wrap {
    flex-direction: column;
    align-items: stretch;
  }

  .guide-stats,
  .qa-grid {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 54px 0;
  }

  .tab-panel {
    padding: 18px;
  }

  .qa-card {
    min-height: auto;
  }

  .qa-modal {
    border-radius: 20px;
  }

  .qa-modal-head {
    padding: 18px;
  }

  .qa-modal-body {
    padding: 18px;
  }

  .qa-modal-foot {
    padding: 12px 18px 18px;
  }

  .qa-modal-foot .btn {
    width: 100%;
  }
}