/* ============================================================
   登录页 · 信息技术交互平台
   固定背景图栈：5 张图随滚动交叉淡化 + 变焦切换（苹果式）
   内容层只做位移/淡入淡出，不再使用模糊
   ============================================================ */

.lp-body {
  --p: 0;
  background: #07080c;
  color: #f5f5f7;
  overflow-x: hidden;
}

.lp-main { position: relative; z-index: 2; }

/* ---------- 固定背景图栈 ---------- */

.lp-bg-stack {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  background: #07080c;
}

.lp-bg-img {
  position: absolute;
  inset: -6%;
  background-size: cover;
  background-position: center;
  opacity: 0;
  transform: scale(1.14);
  will-change: transform, opacity;
  backface-visibility: hidden;
}

.lp-bg-img.is-first { opacity: 1; }

/* 遮罩：保证文字可读 + 上下压暗衔接 */
.lp-shade {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(7, 8, 12, .66) 0%, rgba(7, 8, 12, .22) 38%, rgba(7, 8, 12, .55) 72%, rgba(7, 8, 12, .9) 100%),
    linear-gradient(96deg, rgba(7, 8, 12, .74) 0%, rgba(7, 8, 12, .16) 52%, rgba(7, 8, 12, 0) 100%);
}

/* 细噪点：让照片更有电影质感 */
.lp-grain {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: .06;
  mix-blend-mode: overlay;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ---------- 屏容器 ---------- */

.lp-screen {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 0 clamp(24px, 6vw, 90px);
}

/* 内容：随屏内进度位移 + 淡入淡出（无模糊） */
.lp-content {
  width: 100%;
  max-width: 1160px;
  margin: 0 auto;
  opacity: calc(1 - var(--spa, 0) * 1.55);
  transform: translateY(calc(var(--sp, 0) * 120px)) scale(calc(1 - var(--spa, 0) * .05));
  will-change: transform, opacity;
}

/* ---------- 文字 ---------- */

.lp-kicker {
  font-size: 11.5px;
  letter-spacing: .32em;
  font-weight: 600;
  color: rgba(255, 255, 255, .45);
  margin: 0 0 24px;
}

.lp-title {
  font-size: clamp(54px, 10vw, 132px);
  font-weight: 750;
  letter-spacing: -.045em;
  line-height: 1;
  margin: 0 0 32px;
  color: #ffffff;
  text-shadow: 0 4px 40px rgba(0, 0, 0, .35);
}

.lp-title em {
  font-style: normal;
  color: transparent;
  -webkit-text-stroke: 1.5px rgba(255, 255, 255, .6);
}

.lp-sub {
  font-size: clamp(15px, 1.9vw, 19px);
  line-height: 1.85;
  color: rgba(255, 255, 255, .62);
  margin: 0;
  text-shadow: 0 2px 18px rgba(0, 0, 0, .4);
}

.lp-title-2 {
  font-size: clamp(33px, 5.4vw, 66px);
  font-weight: 720;
  letter-spacing: -.04em;
  line-height: 1.1;
  margin: 0 0 50px;
  color: #ffffff;
  text-shadow: 0 4px 34px rgba(0, 0, 0, .4);
}

.lp-title-2 em {
  font-style: normal;
  color: transparent;
  -webkit-text-stroke: 1.2px rgba(255, 255, 255, .55);
}

/* ---------- 第一屏：下滑提示 ---------- */

.lp-hint {
  margin-top: 60px;
  display: inline-flex;
  align-items: center;
  gap: 14px;
  font-size: 10.5px;
  letter-spacing: .34em;
  color: rgba(255, 255, 255, .48);
}

.lp-hint-line {
  width: 58px;
  height: 1px;
  background: linear-gradient(90deg, rgba(255, 255, 255, .6), rgba(255, 255, 255, 0));
  animation: lpLine 2.2s ease-in-out infinite;
}

@keyframes lpLine {
  0%, 100% { transform: scaleX(.45); transform-origin: left; opacity: .4; }
  50% { transform: scaleX(1); transform-origin: left; opacity: 1; }
}

/* ---------- 第二屏：要点列表 ---------- */

.lp-points {
  display: flex;
  flex-direction: column;
  max-width: 660px;
}

.lp-point {
  display: flex;
  gap: 28px;
  align-items: baseline;
  padding: 25px 0;
  border-top: 1px solid rgba(255, 255, 255, .14);
}
.lp-point:last-child { border-bottom: 1px solid rgba(255, 255, 255, .14); }

.lp-num {
  font-size: 12.5px;
  font-weight: 650;
  letter-spacing: .12em;
  color: rgba(255, 255, 255, .4);
  font-variant-numeric: tabular-nums;
  min-width: 30px;
}

.lp-point h3 {
  font-size: 21px;
  font-weight: 660;
  letter-spacing: -.015em;
  color: #ffffff;
  margin: 0 0 8px;
}

.lp-point p {
  font-size: 15px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .58);
  margin: 0;
}

/* ---------- 第三屏：登录（页面最底部） ---------- */

.lp-login-wrap {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 56px;
  flex-wrap: wrap;
}

.lp-login-copy .lp-title-2 { margin-bottom: 14px; }

.lp-card {
  width: 100%;
  max-width: 470px;
  background: rgba(10, 12, 17, .58);
  -webkit-backdrop-filter: blur(26px) saturate(1.5);
  backdrop-filter: blur(26px) saturate(1.5);
  border: 1px solid rgba(255, 255, 255, .16);
  border-radius: 22px;
  padding: 14px;
  box-shadow: 0 40px 100px rgba(0, 0, 0, .55);
}

.lp-input-row { display: flex; gap: 10px; align-items: stretch; }

.lp-input-row input {
  flex: 1 1 auto;
  min-width: 0;
  border: 1px solid rgba(255, 255, 255, .15);
  background: rgba(255, 255, 255, .07);
  color: #fff;
  border-radius: 14px;
  padding: 16px 19px;
  font-family: inherit;
  font-size: 16.5px;
  transition: border-color .25s, background .25s, box-shadow .25s;
}
.lp-input-row input::placeholder { color: rgba(255, 255, 255, .4); }
.lp-input-row input:focus {
  outline: none;
  border-color: rgba(41, 151, 255, .7);
  background: rgba(255, 255, 255, .12);
  box-shadow: 0 0 0 4px rgba(41, 151, 255, .2);
}

.lp-submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  background: #ffffff;
  color: #07080c;
  font-family: inherit;
  font-size: 15.5px;
  font-weight: 600;
  padding: 16px 25px;
  border-radius: 14px;
  cursor: pointer;
  white-space: nowrap;
  box-shadow: 0 16px 38px rgba(0, 0, 0, .4);
  transition: background .2s, transform .14s, box-shadow .25s;
}
.lp-submit:hover { background: #eceff4; transform: translateY(-1px); }
.lp-submit:active { transform: scale(.98); }
.lp-submit[disabled] { opacity: .55; cursor: not-allowed; transform: none; }
.lp-submit svg { width: 17px; height: 17px; }

.lp-notice {
  min-height: 0;
  padding: 0 10px;
  font-size: 13px;
  color: rgba(255, 255, 255, .6);
}
.lp-notice.is-error { padding-top: 10px; color: #ff8f8f; }
.lp-notice.is-ok { padding-top: 10px; color: #7ce0c4; }

/* ---------- 顶部导航 ---------- */

.lp-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 30;
  padding: 16px 0;
  background: linear-gradient(180deg, rgba(7, 8, 12, .6), rgba(7, 8, 12, 0));
}

.lp-nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 clamp(24px, 6vw, 90px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.lp-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14.5px;
  font-weight: 600;
  letter-spacing: .02em;
  color: #f5f5f7;
  user-select: none;
}

.lp-logo-mark {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: #2997ff;
  box-shadow: 0 0 0 4px rgba(41, 151, 255, .16);
}

.lp-teacher {
  font-size: 13px;
  color: rgba(255, 255, 255, .75);
  text-decoration: none;
  padding: 7px 15px;
  border-radius: 100px;
  border: 1px solid rgba(255, 255, 255, .18);
  background: rgba(255, 255, 255, .05);
  transition: background .22s, color .22s, border-color .22s;
}
.lp-teacher:hover {
  background: rgba(255, 255, 255, .14);
  color: #fff;
  border-color: rgba(255, 255, 255, .32);
  text-decoration: none;
}

/* ---------- 右侧屏指示点 ---------- */

.lp-dots {
  position: fixed;
  right: clamp(14px, 3vw, 34px);
  top: 50%;
  transform: translateY(-50%);
  z-index: 30;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.lp-dots button {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, .5);
  background: transparent;
  cursor: pointer;
  padding: 0;
  transition: background .25s, transform .25s, box-shadow .25s;
}
.lp-dots button.is-active {
  background: #fff;
  transform: scale(1.3);
  box-shadow: 0 0 14px rgba(255, 255, 255, .55);
}

/* ---------- 页脚 ---------- */

.lp-foot {
  position: relative;
  z-index: 2;
  max-width: 1200px;
  margin: 0 auto;
  padding: 26px clamp(24px, 6vw, 90px) 42px;
  color: rgba(255, 255, 255, .3);
  font-size: 11px;
  letter-spacing: .22em;
}

/* ---------- 响应式 ---------- */

@media (max-width: 760px) {
  .lp-title { font-size: clamp(46px, 13.5vw, 76px); }
  .lp-content {
    transform: translateY(calc(var(--sp, 0) * 84px)) scale(calc(1 - var(--spa, 0) * .04));
  }
  .lp-login-wrap { flex-direction: column; align-items: stretch; gap: 32px; }
  .lp-card { max-width: none; }
  .lp-submit { width: 100%; }
  .lp-dots { display: none; }
  .lp-point { gap: 18px; padding: 20px 0; }
  .lp-hint { margin-top: 42px; }
}

@media (prefers-reduced-motion: reduce) {
  .lp-content { transform: none; }
  .lp-hint-line { animation: none; }
  .lp-screen { min-height: 88vh; }
}


/* ---------- 左上角校历徽章 ---------- */

.lp-logo-wrap {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.lp-cal {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 11.5px;
  letter-spacing: .05em;
  color: rgba(255, 255, 255, .8);
  background: rgba(255, 255, 255, .09);
  border: 1px solid rgba(255, 255, 255, .15);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  padding: 5px 13px;
  border-radius: 999px;
  white-space: nowrap;
  font-variant-numeric: tabular-nums;
}

.lp-cal::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #ffb340;
  box-shadow: 0 0 8px rgba(255, 179, 64, .7);
}