/* ============================================================
   管卫东 · 官方主页 — 响应式样式
   断点：手机 < 640px ｜ 平板 ≥ 640px ｜ 桌面 ≥ 900px ｜ 宽屏 ≥ 1200px
   ============================================================ */

/* ---------- 设计变量 ---------- */
:root {
  --navy:        #16233b;
  --navy-soft:   #22335a;
  --gold:        #c9a86a;
  --gold-deep:   #a8843f;
  --paper:       #f7f5f0;
  --card:        #ffffff;
  --ink:         #23272f;
  --ink-soft:    #5a6070;
  --line:        #e6e2d8;
  --wechat:      #07c160;
  --video:       #7c5cff;
  --ai:          #2563eb;
  --radius:      14px;
  --shadow:      0 10px 30px rgba(22, 35, 59, 0.08);
  --shadow-lg:   0 18px 44px rgba(22, 35, 59, 0.16);
  --font-sans:   "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
                 "Noto Sans CJK SC", "Helvetica Neue", Arial, sans-serif;
  --font-serif:  "Songti SC", "STSong", "SimSun", "Noto Serif CJK SC", serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; height: auto; }

a { color: inherit; text-decoration: none; }

.container {
  width: min(1160px, 100% - 2.5rem);
  margin-inline: auto;
}

/* ============================================================
   主视觉 Hero
   ============================================================ */
.hero {
  background: linear-gradient(160deg, var(--navy) 0%, var(--navy-soft) 100%);
  color: #fff;
  padding: 2.75rem 0 3.25rem;
  overflow: hidden;
}

.hero-inner { display: grid; gap: 2rem; justify-items: center; text-align: center; }

.hero-photo {
  position: relative;
  width: min(78vw, 340px);
}

/* 照片后面的金色衬框（与照片完全对齐） */
.hero-photo::before {
  content: "";
  position: absolute;
  inset: 0;
  border: 1.5px solid var(--gold);
  border-radius: var(--radius);
  opacity: 0.75;
  pointer-events: none;
}

.hero-photo img {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  object-fit: cover;
  aspect-ratio: 2 / 3;
}

.hero-name {
  font-family: var(--font-serif);
  font-size: clamp(2.4rem, 6vw + 1rem, 3.4rem);
  font-weight: 700;
  letter-spacing: 0.35em;
  margin-right: -0.35em; /* 抵消字间距带来的右偏移 */
  line-height: 1.25;
}

.hero-kicker {
  color: var(--gold);
  font-size: clamp(0.85rem, 1.5vw + 0.4rem, 1.02rem);
  letter-spacing: 0.3em;
  margin: 1rem 0 0.35rem;
}

.hero-slogan {
  font-family: var(--font-serif);
  font-size: clamp(1.2rem, 2.5vw + 0.6rem, 1.55rem);
  letter-spacing: 0.18em;
  color: #fff;
  margin-bottom: 1.1rem;
}

.hero-intro {
  max-width: 42ch;
  margin-inline: auto;
  color: rgba(255, 255, 255, 0.82);
  font-size: 0.98rem;
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
  margin-top: 1.4rem;
}

.hero-links a {
  font-size: 0.85rem;
  padding: 0.4rem 1rem;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 999px;
  transition: background 0.2s, border-color 0.2s;
}

@media (hover: hover) {
  .hero-links a:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--gold);
  }
}

/* ============================================================
   渠道区块
   ============================================================ */
main.container { padding: 3rem 0 3.5rem; }

.section-title {
  text-align: center;
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 3vw + 0.6rem, 2rem);
  letter-spacing: 0.2em;
  color: var(--navy);
}

.section-sub {
  text-align: center;
  color: var(--ink-soft);
  font-size: 0.9rem;
  margin: 0.4rem 0 2rem;
}

.cards {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: 1fr; /* 手机：单列 */
}

/* ---------- 入口卡片 ---------- */
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.6rem 1.4rem 1.5rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
  animation: rise 0.5s ease both;
}

/* 卡片顶部金色细线 */
.card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--gold), var(--gold-deep));
  opacity: 0.85;
}

.card:nth-child(2) { animation-delay: 0.08s; }
.card:nth-child(3) { animation-delay: 0.16s; }
.card:nth-child(4) { animation-delay: 0.24s; }

@keyframes rise {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: none; }
}

@media (hover: hover) {
  .card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(201, 168, 106, 0.55);
  }
  .card { transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s; }
}

.card-head { margin-bottom: 0.8rem; }

.badge {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  padding: 0.14rem 0.6rem;
  border-radius: 999px;
  color: #fff;
  background: var(--wechat);
  margin-bottom: 0.6rem;
}

.badge-video { background: var(--video); }
.badge-ai    { background: var(--ai); }

.card-type {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--navy);
  letter-spacing: 0.06em;
}

.card-name {
  color: var(--ink-soft);
  font-size: 0.95rem;
  margin-top: 0.15rem;
}

.card-desc {
  flex: 1;
  color: var(--ink);
  font-size: 0.93rem;
  margin-bottom: 1.3rem;
}

/* ---------- 按钮 ---------- */
.btn {
  display: block;
  width: 100%;
  text-align: center;
  font-family: inherit;
  font-size: 0.95rem;
  padding: 0.72rem 1rem;
  border-radius: 10px;
  border: 1.5px solid var(--gold-deep);
  background: transparent;
  color: var(--gold-deep);
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) {
  .btn:hover {
    background: var(--gold-deep);
    color: #fff;
  }
}

.btn:active { transform: scale(0.985); }

.btn-primary {
  background: linear-gradient(135deg, var(--gold), var(--gold-deep));
  border-color: transparent;
  color: #fff;
  font-weight: 600;
}

@media (hover: hover) {
  .btn-primary:hover {
    background: linear-gradient(135deg, var(--gold-deep), var(--gold-deep));
  }
}

/* ============================================================
   二维码弹窗
   ============================================================ */
.modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: grid;
  place-items: center;
  padding: 1.25rem;
}

.modal[hidden] { display: none; }

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(13, 20, 34, 0.6);
  backdrop-filter: blur(2px);
}

.modal-box {
  position: relative;
  background: var(--card);
  border-radius: 18px;
  padding: 1.6rem 1.6rem 1.3rem;
  width: min(340px, 100%);
  text-align: center;
  box-shadow: var(--shadow-lg);
  animation: pop 0.22s ease both;
}

@keyframes pop {
  from { opacity: 0; transform: scale(0.94); }
  to   { opacity: 1; transform: scale(1); }
}

.modal-close {
  position: absolute;
  top: 0.55rem; right: 0.6rem;
  width: 2rem; height: 2rem;
  border: none;
  border-radius: 50%;
  background: transparent;
  color: var(--ink-soft);
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
}

@media (hover: hover) {
  .modal-close:hover { background: #f0ede5; color: var(--ink); }
}

.modal-box h3 {
  font-size: 1.05rem;
  color: var(--navy);
  letter-spacing: 0.04em;
  margin-bottom: 1rem;
}

#modal-qr {
  width: min(70vw, 240px);
  margin-inline: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.4rem;
  background: #fff;
}

.modal-hint {
  margin-top: 0.9rem;
  font-size: 0.82rem;
  color: var(--ink-soft);
}

body.modal-open { overflow: hidden; }

/* ============================================================
   页脚
   ============================================================ */
.footer {
  background: var(--navy);
  color: rgba(255, 255, 255, 0.72);
  text-align: center;
  padding: 1.8rem 0 2.2rem;
  font-size: 0.85rem;
}

.footer-meta { margin-top: 0.25rem; color: rgba(255, 255, 255, 0.5); }

.footer-icp { margin-top: 0.4rem; font-size: 0.78rem; color: rgba(255, 255, 255, 0.42); }

.footer-icp a { color: inherit; }

.footer-icp a:hover { text-decoration: underline; }

/* ============================================================
   响应式断点
   ============================================================ */

/* ---------- ≥640px：平板 ---------- */
@media (min-width: 640px) {
  .hero { padding: 3.5rem 0 4rem; }

  .hero-photo { width: min(56vw, 320px); }

  .hero-intro { font-size: 1.02rem; }

  .cards { grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
}

/* ---------- ≥900px：桌面 ---------- */
@media (min-width: 900px) {
  .hero-inner {
    grid-template-columns: 420px 1fr;
    gap: 3.5rem;
    align-items: center;
    justify-items: start;
    text-align: left;
  }

  .hero-photo { width: 100%; }

  .hero-intro { margin-inline: 0; max-width: 46ch; }

  .hero-links { justify-content: flex-start; }

  main.container { padding: 4rem 0 4.5rem; }

  .btn { width: auto; min-width: 180px; }
}

/* ---------- ≥1200px：宽屏，四卡并排 ---------- */
@media (min-width: 1200px) {
  .cards { grid-template-columns: repeat(4, 1fr); }
}

/* ---------- 弱化动态效果（用户偏好） ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .card { animation: none; }
  .modal-box { animation: none; }
}

/* ============================================================
   区块通用（平台 / 渠道 / 产品）
   ============================================================ */
.block + .block {
  margin-top: 3rem;
  padding-top: 3rem;
  border-top: 1px solid var(--line);
}

.block .section-sub { margin-bottom: 0; }

/* ---------- 双支柱 ---------- */
.pillars {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: 1fr; /* 手机：上下排列 */
  margin-top: 2rem;
}

.pillar {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 4px solid var(--gold);
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem;
  box-shadow: var(--shadow);
}

.pillar h3 {
  color: var(--navy);
  font-size: 1.15rem;
  letter-spacing: 0.05em;
  margin-bottom: 0.4rem;
}

.pillar p { color: var(--ink-soft); font-size: 0.93rem; }

@media (min-width: 640px) {
  .pillars { grid-template-columns: repeat(2, 1fr); }
}

/* ---------- 基本逻辑流程线 ---------- */
.flow {
  display: flex;
  flex-direction: column; /* 手机：纵向箭头向下 */
  align-items: center;
  gap: 0.8rem;
  margin-top: 2.2rem;
  background: linear-gradient(160deg, var(--navy) 0%, var(--navy-soft) 100%);
  border-radius: var(--radius);
  padding: 1.6rem 1.2rem;
}

.flow-step {
  text-align: center;
  color: #fff;
  font-weight: 600;
  font-size: 1.02rem;
  letter-spacing: 0.05em;
  line-height: 1.5;
}

.flow-step small {
  display: block;
  color: rgba(255, 255, 255, 0.62);
  font-weight: 400;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
}

/* 重点步骤：金色高亮 */
.flow-step.key { color: var(--gold); }

.flow-step.key small { color: rgba(255, 224, 178, 0.9); }

.flow-arrow {
  color: var(--gold);
  font-size: 1.35rem;
  line-height: 1;
  transform: rotate(90deg);
}

@media (min-width: 900px) {
  .flow { flex-direction: row; justify-content: center; gap: 2.4rem; }
  .flow-arrow { transform: none; }
}

/* ---------- 服务号徽标（金色） ---------- */
.badge-service { background: var(--gold-deep); }

/* ---------- 核心产品 ---------- */
.products {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: 1fr; /* 手机：单列 */
  margin-top: 2rem;
}

.product {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.5rem 1.4rem 1.4rem;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
}

.product h3 {
  color: var(--navy);
  font-size: 1.05rem;
  letter-spacing: 0.04em;
  margin-bottom: 0.5rem;
}

.product p {
  flex: 1;
  color: var(--ink-soft);
  font-size: 0.9rem;
  margin-bottom: 1.2rem;
}

.product .btn { margin-top: auto; }

/* ---------- 第一重点横幅卡（教育考试起点） ---------- */
.product-lead {
  grid-column: 1 / -1;
  flex-direction: column;
  align-items: flex-start;
  gap: 1.1rem;
  background: linear-gradient(160deg, var(--navy) 0%, var(--navy-soft) 100%);
  border: 1px solid rgba(201, 168, 106, 0.55);
}

.product-lead h3 { color: #fff; font-size: 1.2rem; }

.product-lead p { color: rgba(255, 255, 255, 0.8); }

.product-lead .btn { margin-top: 0; }

@media (min-width: 900px) {
  .product-lead {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
  }
}

@media (min-width: 640px) {
  .products { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1200px) {
  .products { grid-template-columns: repeat(4, 1fr); }
}

/* ---------- 卡片内多按钮间距 ---------- */
.card .btn + .btn { margin-top: 0.6rem; }