/* ============================================
   段位品牌战略 · 官网样式
   参考：to2kaku.com 左右分区极简作品集版式
   品牌色：蓝 / 黑 / 白
   ============================================ */

:root {
  --c-blue: #1b4db1;
  --c-blue-deep: #143a86;
  --c-black: #0c0c0c;
  --c-ink: #141414;
  --c-gray: #6b6b6b;
  --c-line: #e8e8e8;
  --c-bg: #f5f5f3;          /* 侧栏浅灰 */
  --c-panel: #ffffff;       /* 内容区白 */

  --font-serif: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-sans: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif;
  --font-yahei: "Microsoft YaHei", "Microsoft YaHei UI", sans-serif;

  --side-w: 300px;
}

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

html, body { height: 100%; }

body {
  font-family: var(--font-sans);
  font-weight: 300;
  color: var(--c-ink);
  background: var(--c-panel);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;   /* 禁止整页滚动，改为面板切换 */
}

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

/* ============ 应用骨架 ============ */
.app {
  display: flex;
  height: 100vh;
  width: 100%;
}

/* ============ 左侧侧边栏 ============ */
.sidebar {
  width: var(--side-w);
  flex-shrink: 0;
  background: #ffffff;   /* 侧边栏：白色 */
  display: flex;
  flex-direction: column;
  padding: 36px 22px 28px;
  border-right: 1px solid var(--c-line);
  z-index: 10;
}

.logo {
  display: block;
  width: 72%;
  margin: 0 auto 40px;    /* LOGO 在侧边栏内水平居中 */
}
.logo-img {
  width: 100%;
  max-width: 100%;
  height: auto;
  display: block;
}

.side-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  /* 25.25% = LOGO 居中左留白 14% + LOGO 图片左侧透明边距缩放后的 11.25%
     → 导航文字左边缘与 LOGO「段位」二字的左边缘精确对齐（任意侧栏宽度均成立） */
  padding: 0 5% 0 25.25%;
}
.side-link {
  position: relative;
  display: block;
  padding: 13px 0;
  text-align: left;                 /* 参照 LOGO 左对齐 */
  font-family: var(--font-yahei);   /* 微软雅黑 */
  font-size: 16px;
  font-weight: 500;                 /* 中性字重，不再偏细 */
  letter-spacing: .1em;
  color: var(--c-ink);
  cursor: pointer;
  transition: color .25s ease, background .25s ease;
}
.side-link::before {
  content: "";
  position: absolute;
  left: 0; bottom: 7px;
  width: 0; height: 2px;
  background: var(--c-blue);
  transition: width .25s ease;
}
.side-link:hover { color: var(--c-blue); }
.side-link.active {
  color: var(--c-blue);
  font-weight: 700;
  background: none;
}
.side-link.active::before {
  width: 20px;    /* 当前项：文字左下方短横线 */
}

.side-intro {
  margin-top: auto;
  font-family: var(--font-yahei);
  font-size: 12px;
  font-weight: 400;
  line-height: 2;
  color: var(--c-gray);
}
.side-copy {
  margin-top: 20px;
  font-family: var(--font-yahei);
  font-size: 11px;
  letter-spacing: .06em;
  color: #b5b5b5;
}

/* ============ 右侧内容区 ============ */
.content {
  flex: 1;
  position: relative;
  overflow: hidden;
  background: var(--c-bg);   /* 内容区：浅灰 */
}

.panel {
  position: absolute;
  inset: 0;
  padding: 80px 64px 60px;
  overflow-y: auto;
  background: transparent;
  opacity: 0;
  visibility: hidden;
  transform: translateY(18px);
  transition: opacity .5s ease, transform .5s ease, visibility .5s;
}
.panel.active {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

/* 内容最大宽度，居中偏左 */
.panel > * { max-width: 1040px; }

/* ============ 首页 ============ */
#panel-home {
  display: flex;
  align-items: center;
  overflow-y: auto;
  padding: 48px;
}
/* 白色画布卡片，内嵌书法主视觉 */
.home-art {
  width: 100%;
  max-width: none;          /* 覆盖 .panel > * 的 1040px 限制 */
  margin: auto;             /* 垂直居中且溢出时可滚动 */
  background: #fff;
  padding: clamp(18px, 2vw, 34px);
  box-shadow: 0 18px 44px rgba(0, 0, 0, .10), 0 2px 8px rgba(0, 0, 0, .04);
}
.home-art img {
  width: 100%;
  height: auto;
  display: block;
}
.eyebrow {
  font-size: 13px;
  letter-spacing: .32em;
  color: var(--c-blue);
  text-transform: uppercase;
  margin-bottom: 26px;
}
.hero-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(40px, 6vw, 76px);
  line-height: 1.2;
  letter-spacing: .02em;
  color: var(--c-black);
}
.hero-title em { font-style: normal; color: var(--c-blue); }
.hero-desc {
  margin-top: 32px;
  font-size: 16px;
  color: var(--c-gray);
  line-height: 2;
}
.hero-cta {
  margin-top: 42px;
  display: flex;
  gap: 18px;
}
.btn {
  display: inline-block;
  font-size: 14px;
  letter-spacing: .1em;
  padding: 14px 34px;
  transition: all .3s ease;
  cursor: pointer;
  border: none;
}
.btn-solid { background: var(--c-black); color: #fff; }
.btn-solid:hover { background: var(--c-blue); }
.btn-ghost { border: 1px solid var(--c-black); color: var(--c-black); background: none; }
.btn-ghost:hover { background: var(--c-black); color: #fff; }

/* 首页主视觉图 */
.hero-visual {
  margin-top: 52px;
}
.hero-visual img {
  width: 100%;
  aspect-ratio: 16 / 7;
  object-fit: cover;
  object-position: center 42%;
  display: block;
  box-shadow: 0 14px 34px rgba(0, 0, 0, .12);
}

/* 荣誉资质 */
.honor {
  margin-top: 64px;
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 44px;
  align-items: center;
  border-top: 1px solid var(--c-line);
  padding-top: 56px;
}
.honor-img img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  display: block;
  box-shadow: 0 10px 26px rgba(0, 0, 0, .12);
}
.honor-title {
  font-family: var(--font-serif);
  font-size: 22px;
  font-weight: 600;
  color: var(--c-black);
  margin-bottom: 16px;
}
.honor-desc {
  font-size: 14px;
  color: var(--c-gray);
  margin-bottom: 14px;
}
.honor-desc strong { color: var(--c-blue); font-weight: 600; }
.honor-note {
  font-size: 12px;
  letter-spacing: .08em;
  color: #b0b0b0;
}

/* ============ 面板标题 ============ */
.panel-head { margin-bottom: 46px; }
.panel-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(28px, 3.4vw, 40px);
  letter-spacing: .03em;
  color: var(--c-black);
  display: flex;
  align-items: baseline;
  gap: 18px;
}
.panel-en {
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: .3em;
  color: #b5b5b5;
  font-weight: 400;
  text-transform: uppercase;
}

/* ============ 关于我们（参考版式：窄栏居中，左文右图） ============ */
.about-wrap {
  width: 100%;
  max-width: 680px;
  margin: 0 auto;
}
.about-h1 {
  font-family: var(--font-yahei);
  font-weight: 700;
  font-size: clamp(24px, 2.2vw, 30px);
  color: var(--c-ink);
  letter-spacing: .02em;
  line-height: 1.4;
}
.about-sub {
  font-family: var(--font-yahei);
  font-weight: 700;
  font-size: clamp(16px, 1.5vw, 20px);
  color: var(--c-ink);
  line-height: 1.75;
  margin-top: 16px;
}
.about-row {
  display: flex;
  gap: 7%;
  margin-top: 52px;
  align-items: flex-start;
}
.about-txt { flex: 1 1 50%; }
.about-txt h3 {
  font-family: var(--font-yahei);
  font-size: 17px;
  font-weight: 700;
  color: var(--c-ink);
}
.about-txt p {
  margin-top: 12px;
  font-size: 13px;
  line-height: 2.05;
  color: #555;
  text-align: justify;
}
.about-pic {
  flex: 1 1 50%;
  min-height: 200px;
  background: #fff;
  box-shadow: 0 10px 30px rgba(0, 0, 0, .05);
}

/* ============ 作品案例 ============ */
#panel-works {
  background: transparent;   /* 继承内容区浅灰 */
  display: flex;
  flex-direction: column;
  align-items: center;       /* 水平居中 */
  overflow-y: auto;
}
.works-grid {
  width: 100%;
  max-width: 1360px;
  margin: auto 0;            /* 有剩余空间时垂直居中，溢出时可正常滚动到顶部 */
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 46px 40px;
  justify-items: center;
  align-content: center;
  padding: 24px 0;
}
.work-card {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  cursor: pointer;
}
/* 图片卡片：横版图 + 底部一条白边（参考用户草图） */
.work-frame {
  width: 100%;
  padding: 0;                /* 去掉底部白边，图片铺满卡片 */
  background: #fff;
  border: 1px solid rgba(0, 0, 0, .04);   /* 极淡描边 */
  box-shadow: 0 8px 22px rgba(0, 0, 0, .09), 0 1px 4px rgba(0, 0, 0, .04);
  transition: transform .35s ease, box-shadow .35s ease;
}
.work-card:hover .work-frame {
  transform: translateY(-5px);
  box-shadow: 0 18px 36px rgba(0, 0, 0, .13), 0 3px 8px rgba(0, 0, 0, .05);
}
.work-thumb {
  position: relative;
  aspect-ratio: 10 / 7;      /* 横版图 */
  background: #f0f0ed;
  overflow: hidden;
}
.work-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top center;   /* 取案例长图首屏 */
  display: block;
}
.work-thumb svg { width: 100%; height: 100%; display: block; }
.work-thumb .overlay {
  position: absolute;
  inset: 0;
  background: rgba(27, 77, 177, 0);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: all .35s ease;
}
.work-card:hover .overlay { background: rgba(27, 77, 177, .82); opacity: 1; }
.overlay span {
  color: #fff;
  font-size: 12px;
  letter-spacing: .2em;
  transform: translateY(8px);
  transition: transform .35s ease;
}
.work-card:hover .overlay span { transform: translateY(0); }
/* 卡片不放文字（参考用户草图） */

/* ============ 段位方法 ============ */
.method-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  border-top: 1px solid var(--c-line);
}
.step { padding: 42px 30px 0 0; }
.step-num {
  font-family: var(--font-serif);
  font-size: 18px;
  color: var(--c-blue);
  display: block;
  margin-bottom: 18px;
}
.step-title {
  font-family: var(--font-serif);
  font-size: 19px;
  color: var(--c-black);
  font-weight: 600;
  margin-bottom: 12px;
}
.step-desc { font-size: 13px; color: var(--c-gray); }
.method-quote {
  margin-top: 72px;
  text-align: center;
  padding: 52px 20px;
  border-top: 1px solid var(--c-line);
  border-bottom: 1px solid var(--c-line);
}
.method-quote p {
  font-family: var(--font-serif);
  font-size: clamp(18px, 2.2vw, 26px);
  color: var(--c-black);
  font-weight: 500;
  line-height: 1.8;
}

/* ============ 联系我们 ============ */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
}
.contact-lead {
  font-family: var(--font-serif);
  font-size: clamp(22px, 2.8vw, 34px);
  line-height: 1.7;
  color: var(--c-black);
  font-weight: 500;
  margin-bottom: 22px;
}
.contact-desc { color: var(--c-gray); font-size: 14px; max-width: 420px; }
.contact-info { display: flex; flex-direction: column; }
.contact-item {
  display: flex;
  align-items: baseline;
  padding: 20px 0;
  border-bottom: 1px solid var(--c-line);
}
.contact-label {
  width: 64px;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--c-gray);
  flex-shrink: 0;
}
.contact-value { font-size: 15px; color: var(--c-black); transition: color .3s ease; }
a.contact-value:hover { color: var(--c-blue); }

/* ============ 响应式 ============ */
@media (max-width: 860px) {
  :root { --side-w: 230px; }
  .panel { padding: 64px 36px 48px; }
  .contact-grid { grid-template-columns: 1fr; gap: 32px; }
  .about-row { flex-direction: column; gap: 22px; }
  .about-pic { width: 100%; min-height: 160px; }
  .method-steps { grid-template-columns: 1fr 1fr; }
  .works-grid { grid-template-columns: repeat(2, 1fr); gap: 28px 20px; }
  .honor { grid-template-columns: 1fr; gap: 28px; }
}

@media (max-width: 600px) {
  .app { flex-direction: column; height: auto; }
  body { overflow: auto; }
  .sidebar {
    width: 100%;
    flex-direction: row;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
    padding: 16px 18px;
    border-right: none;
    border-bottom: 1px solid var(--c-line);
  }
  .logo { margin-bottom: 0; margin-left: 0; margin-right: 0; width: auto; }
  .logo-img { width: auto; max-width: none; height: 40px; }
  .logo-box { width: 40px; height: 40px; font-size: 15px; }
  .logo-en { display: none; }
  .side-nav { flex-direction: row; gap: 2px; overflow-x: auto; padding: 0; }
  .side-link { padding: 8px 10px; text-align: left; border-left: none; border-bottom: 2px solid transparent; }
  .side-link.active { padding-left: 10px; border-bottom-color: var(--c-blue); }
  .side-link::before { display: none; }
  .side-link .en { display: none; }
  .side-intro, .side-copy { display: none; }
  .content { position: relative; height: calc(100vh - 72px); }
  .panel { padding: 40px 22px; }
  #panel-home { padding: 24px 16px; }
  .works-grid { grid-template-columns: 1fr; }
  .method-steps { grid-template-columns: 1fr; }
  .step { padding-right: 0; padding-top: 30px; }
}


/* ============ 段位方法 · 立体书架 ============ */
#panel-method {
  display: flex;
  align-items: center;
}
.bookshelf {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 64px 60px;
  max-width: 1020px;
  margin: auto;              /* 垂直居中且溢出时可滚动 */
  perspective: 2400px;
}
.book3d {
  position: relative;
  aspect-ratio: 1 / 1.06;
  transition: transform .45s cubic-bezier(.2, .8, .3, 1.1);
  cursor: pointer;
}
.book3d:hover {
  transform: translateY(-12px);
}
.bk-photo {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}
.bk-shadow {
  position: absolute;
  left: -2%; right: 2%; bottom: -26px;
  height: 42px;
  border-radius: 50%;
  background: radial-gradient(ellipse at center, rgba(0, 0, 0, .38) 0%, rgba(0, 0, 0, .16) 48%, transparent 74%);
  filter: blur(6px);
  transform: translateZ(-14px);
}
.bk-cover, .bk-back {
  position: absolute;
  inset: 0;
  background: #fff;
  border: 1px solid rgba(0, 0, 0, .05);
}
.bk-cover {
  transform: translateZ(20px);
  border-radius: 2px 7px 7px 2px;
  background: linear-gradient(100deg, #ffffff 76%, #f6f6f3 94%, #eeeeeb 100%);
  box-shadow: 0 16px 30px rgba(0, 0, 0, .13);
  padding: 20px 22px 18px;
  display: flex;
  flex-direction: column;
}
.bk-back {
  transform: translateZ(-20px);
  background: #f7f7f5;
}
.bk-spine {
  position: absolute;
  top: 0; bottom: 0; left: 0;
  width: 40px;
  transform-origin: left center;
  transform: translateZ(-20px) rotateY(90deg);
  background: linear-gradient(90deg, #d2d2cf 0%, #ececea 42%, #ffffff 78%, #fdfdfc 100%);
  border-radius: 3px 0 0 3px;
}
.bk-pages {
  position: absolute;
  top: 5px; bottom: 5px; right: 2px;
  width: 40px;
  transform-origin: right center;
  transform: translateZ(-20px) rotateY(-90deg);
  background: repeating-linear-gradient(180deg, #ffffff 0 2px, #dcdcd6 2px 3px);
}
.bk-top {
  position: absolute;
  top: 0; left: 2px; right: 2px;
  height: 40px;
  transform-origin: top center;
  transform: translateZ(-20px) rotateX(-90deg);
  background: linear-gradient(90deg, #f4f4f1 0%, #ffffff 30%, #fdfdfc 100%);
}
.bc-logo {
  font-family: var(--font-yahei);
  font-weight: 900;
  font-size: 21px;
  color: #0c0c0c;
  line-height: 1.15;
  text-align: left;          /* 参考图：Logo 居左上 */
}
.bc-logo .bc-r { font-size: 10px; vertical-align: super; }
.bc-logo em {
  display: block;
  font-style: normal;
  font-weight: 700;
  font-size: 10px;
  letter-spacing: .42em;
  color: #0c0c0c;
  margin-top: 2px;
}
/* 参考图：粗环 + 大实心圆点的蓝靶心 */
.bc-mark {
  width: 118px; height: 118px;
  border: 21px solid #2456e6;
  border-radius: 50%;
  display: grid;
  place-items: center;
  margin: 18px auto 0;
  flex: none;
}
.bc-mark b {
  width: 55px; height: 55px;
  background: #2456e6;
  border-radius: 50%;
}
/* 参考图：特大号粗宋体书名，几乎撑满封面宽度 */
.bc-title {
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(30px, 3vw, 48px);
  color: #0c0c0c;
  letter-spacing: .02em;
  white-space: nowrap;
  margin-top: auto;          /* 书名沉底，贴近参考图 */
  text-align: center;
  line-height: 1.15;
}
.bc-title.t4 { font-size: clamp(36px, 3.5vw, 55px); }
.bc-title.t3 { font-size: clamp(42px, 4.3vw, 68px); }
.bc-sub {
  font-family: var(--font-yahei);
  font-size: 10px;
  color: #2456e6;             /* 参考图：蓝色小字 */
  font-weight: 700;
  letter-spacing: .04em;
  margin-top: 12px;
  line-height: 1.9;
  text-align: left;           /* 参考图：左对齐 */
}
.bc-note {
  margin-top: 6px;
  font-family: var(--font-yahei);
  font-size: 9px;
  color: #141414;
  font-weight: 700;
  line-height: 1.85;
  letter-spacing: .02em;
  text-align: left;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ============ 书籍详情弹层（左书 + 右简介） ============ */
.book-modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
  background: rgba(243, 243, 240, .34);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  opacity: 0;
  visibility: hidden;
  transition: opacity .4s ease, visibility .4s;
}
.book-modal.open { opacity: 1; visibility: visible; }
.book-close {
  position: absolute;
  top: 22px; right: 34px;
  width: 46px; height: 46px;
  border: none;
  background: #fff;
  border-radius: 50%;
  font-size: 26px;
  line-height: 1;
  color: #333;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(0, 0, 0, .12);
  transition: transform .25s ease, color .25s ease;
  z-index: 5;
}
.book-close:hover { transform: rotate(90deg); color: var(--c-blue); }
.flipbook {
  position: relative;
  display: flex;
  width: min(940px, 90vw);
  max-height: 78vh;
  background: #fff;
  box-shadow: 0 40px 90px rgba(0, 0, 0, .28);
  transform: scale(.88) translateY(24px);
  transition: transform .5s cubic-bezier(.2, .9, .25, 1.15);
}
.book-modal.open .flipbook { transform: scale(1) translateY(0); }

/* 左侧：立体书封面 */
.fb-left {
  flex: 0 0 42%;
  padding: 40px 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(158deg, #f7f7f4, #ebebe8);
  border-right: 1px solid #e8e8e4;
  perspective: 1500px;
}
.fb-cover {
  width: 100%;
  max-width: 296px;
  aspect-ratio: 1 / 1.06;
  display: flex;
  align-items: center;
}

/* 右侧：简介 */
.fb-right {
  flex: 1;
  padding: 52px 48px;
  overflow-y: auto;
}
.md-no {
  font-size: 11px;
  letter-spacing: .28em;
  color: var(--c-blue);
  margin-bottom: 16px;
}
.md-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 32px;
  color: #0c0c0c;
  letter-spacing: .06em;
}
.md-sub {
  margin-top: 12px;
  font-size: 13px;
  color: #9a9a9a;
  letter-spacing: .1em;
}
.md-rule {
  width: 46px; height: 2px;
  background: var(--c-blue);
  margin: 24px 0 26px;
}
.md-body p {
  font-size: 14.5px;
  line-height: 2.05;
  color: #333;
  margin-bottom: 20px;
}
.md-body p:last-child { margin-bottom: 0; }

@media (max-width: 900px) {
  .bookshelf { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 44px 30px; }
  .book3d { transform: none; }
  .flipbook { width: 94vw; flex-direction: column; max-height: 86vh; }
  .fb-left { flex: none; padding: 28px 22px; border-right: none; border-bottom: 1px solid #e8e8e4; }
  .fb-cover { max-width: 240px; }
  .fb-right { padding: 30px 26px 34px; }
  .md-title { font-size: 26px; }
}
@media (max-width: 600px) {
  .bookshelf { gap: 34px 22px; }
  .bk-cover { padding: 12px 14px; }
  .bc-mark { width: 60px; height: 60px; border-width: 11px; }
  .bc-mark b { width: 28px; height: 28px; }
  .bc-title { font-size: 18px; }
  .bc-title.t4 { font-size: 22px; }
  .bc-title.t3 { font-size: 27px; }
  .book-modal { padding: 14px; }
  .md-title { font-size: 22px; }
  .md-body p { font-size: 13.5px; line-height: 1.9; }
}

/* ============ 联系我们 · 咨询表单 ============ */
.contact-form {
  width: min(760px, 100%);
  margin: 46px auto 0;
  background: var(--c-panel);
  border: 1px solid var(--c-line);
  padding: 40px 44px 34px;
}
.cf-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 20px;
  letter-spacing: .05em;
  color: var(--c-ink);
  margin-bottom: 26px;
}
.cf-row { display: grid; grid-template-columns: 1fr 1fr; gap: 0 22px; }
.cf-field { display: block; margin-bottom: 20px; }
.cf-label {
  display: block;
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-gray);
  margin-bottom: 9px;
}
.cf-label i { color: var(--c-blue); font-style: normal; }
.cf-field input,
.cf-field select,
.cf-field textarea {
  width: 100%;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--c-ink);
  background: var(--c-panel);
  border: 1px solid #e4e4e0;
  border-radius: 2px;
  padding: 12px 14px;
  outline: none;
  transition: border-color .25s ease, box-shadow .25s ease;
}
.cf-field textarea { resize: vertical; line-height: 1.9; }
.cf-field input:focus,
.cf-field select:focus,
.cf-field textarea:focus {
  border-color: var(--c-blue);
  box-shadow: 0 0 0 3px rgba(27, 77, 177, .08);
}
.cf-foot { display: flex; align-items: center; gap: 20px; flex-wrap: wrap; margin-top: 4px; }
.cf-submit {
  font-family: var(--font-yahei);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: .16em;
  color: #fff;
  background: var(--c-blue);
  border: none;
  padding: 14px 40px;
  cursor: pointer;
  transition: background .3s ease, transform .3s ease;
}
.cf-submit:hover { background: var(--c-blue-deep); transform: translateY(-2px); }
.cf-submit:disabled { background: #b9c3d6; cursor: not-allowed; transform: none; }
.cf-status { font-size: 13px; color: var(--c-gray); }
.cf-status.ok { color: var(--c-blue); }
.cf-status.err { color: #c0392b; }
.cf-tip { margin-top: 22px; font-size: 11px; letter-spacing: .1em; color: #a3a3a0; }
@media (max-width: 760px) {
  .contact-form { padding: 28px 22px 26px; margin-top: 34px; }
  .cf-row { grid-template-columns: 1fr; }
}

/* ============ 案例详情（第二界面 · 图片查看器） ============ */
.case-viewer {
  position: fixed;
  inset: 0;
  z-index: 120;
  background: var(--c-bg);          /* 与内容区一致的浅灰 */
  opacity: 0;
  visibility: hidden;
  transition: opacity .4s ease, visibility .4s;
}
.case-viewer.open { opacity: 1; visibility: visible; }
.cv-bar {
  position: absolute;
  top: 0; left: 0; right: 0;
  z-index: 2;
  display: flex;
  justify-content: flex-end;
  padding: 18px 28px;
  pointer-events: none;
}
.cv-close {
  pointer-events: auto;
  background: #fff;
  border: 1px solid rgba(0, 0, 0, .1);
  color: var(--c-ink);
  font-size: 12px;
  letter-spacing: .18em;
  padding: 9px 20px;
  cursor: pointer;
  box-shadow: 0 2px 10px rgba(0, 0, 0, .06);
  transition: all .3s ease;
}
.cv-close:hover { background: var(--c-blue); border-color: var(--c-blue); color: #fff; }
.cv-scroll {
  position: absolute;
  inset: 0;
  overflow-y: auto;
  display: flex;
  justify-content: center;
  padding: 64px 24px 56px;
}
.cv-scroll img {
  width: min(860px, 92vw);
  height: auto;
  align-self: flex-start;
  box-shadow: 0 24px 60px rgba(0, 0, 0, .14), 0 2px 8px rgba(0, 0, 0, .05);
  background: #fff;
}

/* ---------- 案例查看器：底部返回栏 + 结束提示 ---------- */
.cv-foot {
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 4;
  display: none;                 /* 仅移动端显示 */
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 12px calc(12px + env(safe-area-inset-bottom, 0px));
  background: linear-gradient(180deg, rgba(245, 245, 243, 0) 0%, rgba(245, 245, 243, .92) 38%, rgba(245, 245, 243, .98) 100%);
}
.cv-foot button {
  font-family: var(--font-yahei);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--c-ink);
  background: #fff;
  border: 1px solid rgba(0, 0, 0, .12);
  padding: 11px 14px;
  cursor: pointer;
  white-space: nowrap;
  box-shadow: 0 3px 12px rgba(0, 0, 0, .08);
  transition: background .25s ease, color .25s ease, border-color .25s ease;
}
.cv-foot button:active { transform: translateY(1px); }
.cv-back {
  color: #fff !important;
  background: var(--c-blue) !important;
  border-color: var(--c-blue) !important;
  font-weight: 700;
}
.case-end {
  width: min(860px, 92vw);
  margin: 22px auto 0;
  text-align: center;
  font-size: 12px;
  letter-spacing: .08em;
  color: #9a9a9a;
  display: none;                 /* 仅移动端显示 */
}

/* ============================================
   移动端适配（手机 / 平板竖屏）
   桌面为「左固定栏 + 右内容区」；手机改为
   「顶部固定条 + 汉堡下拉导航 + 单列内容」
   ============================================ */
.nav-toggle { display: none; }

@media (max-width: 760px) {
  /* ---------- 骨架：顶部条 + 内容区 ---------- */
  .app {
    flex-direction: column;
    height: 100vh;
    height: 100dvh;            /* 适配手机浏览器地址栏 */
  }
  body { overflow: hidden; }

  .sidebar {
    position: fixed;
    top: 0; left: 0; right: 0;
    height: 56px;
    width: 100%;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 0 14px;
    background: #fff;
    border-right: none;
    border-bottom: 1px solid var(--c-line);
    box-shadow: 0 2px 12px rgba(0, 0, 0, .05);
    z-index: 200;
  }

  /* LOGO 缩小置于左上（内联样式需 !important 覆盖） */
  .logo { width: auto; margin: 0; }
  .logo-img {
    width: auto !important;
    height: 28px !important;
    max-width: 60vw;
  }

  /* 汉堡按钮 */
  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 42px; height: 42px;
    padding: 0 9px;
    background: none;
    border: none;
    cursor: pointer;
    flex-shrink: 0;
  }
  .nav-toggle span {
    display: block;
    height: 2px;
    width: 100%;
    background: var(--c-ink);
    border-radius: 2px;
    transition: transform .3s ease, opacity .25s ease;
  }
  .sidebar.nav-open .nav-toggle span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
  .sidebar.nav-open .nav-toggle span:nth-child(2) { opacity: 0; }
  .sidebar.nav-open .nav-toggle span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

  /* 导航：下拉全宽菜单 */
  .side-nav {
    position: fixed;
    top: 56px; left: 0; right: 0;
    flex-direction: column;
    gap: 0;
    padding: 4px 18px 16px;
    background: #fff;
    border-bottom: 1px solid var(--c-line);
    box-shadow: 0 16px 34px rgba(0, 0, 0, .10);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity .28s ease, transform .28s ease, visibility .28s;
    z-index: 199;
    max-height: calc(100dvh - 56px);
    overflow-y: auto;
  }
  .sidebar.nav-open .side-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  .side-link {
    padding: 15px 2px;
    font-size: 16px;
    letter-spacing: .08em;
    border-bottom: 1px solid #f1f1ee;
  }
  .side-link:last-child { border-bottom: none; }
  .side-link::before { display: none; }
  .side-link.active { color: var(--c-blue); }

  /* 侧栏文字只在展开菜单里出现，放在底部 */
  .side-intro, .side-copy {
    display: none;
  }

  /* 内容区：顶栏之下整屏滚动 */
  .content {
    height: calc(100vh - 56px);
    height: calc(100dvh - 56px);
    margin-top: 56px;
    overflow: hidden;
  }
  .panel {
    padding: 22px 16px 40px;
    transform: translateY(10px);
  }
  .panel > * { max-width: 100%; }
  .panel-head { margin-bottom: 26px; }
  .panel-title { font-size: 24px; }

  /* ---------- 首页 ---------- */
  #panel-home { padding: 14px 12px 26px; }
  .home-art { padding: 12px; box-shadow: 0 10px 26px rgba(0, 0, 0, .10); }

  /* ---------- 关于我们 ---------- */
  .about-wrap { max-width: 100%; }
  .about-h1 { font-size: 22px; }
  .about-sub { font-size: 15px; line-height: 1.8; }
  .about-row { flex-direction: column; gap: 16px; margin-top: 30px; }
  .about-txt h3 { font-size: 16px; }
  .about-txt p { font-size: 14px; line-height: 1.95; margin-top: 10px; }
  .about-pic { width: 100%; min-height: 150px; }

  /* ---------- 作品案例：单列大图 ---------- */
  #panel-works { padding: 20px 14px 34px; }
  .works-grid {
    grid-template-columns: 1fr;
    gap: 20px;
    max-width: 100%;
    margin: 0;
    padding: 0;
  }

  /* ---------- 段位方法：单列大书 ---------- */
  #panel-method { padding: 20px 14px 34px; align-items: flex-start; }
  .bookshelf {
    grid-template-columns: 1fr;
    gap: 26px;
    max-width: 340px;
    margin: 0 auto;
  }
  .book3d:hover { transform: none; }

  /* ---------- 联系我们 ---------- */
  .contact-grid { grid-template-columns: 1fr; gap: 24px; }
  .contact-lead { font-size: 20px; }
  .contact-desc { font-size: 14px; max-width: 100%; }
  .contact-item { padding: 15px 0; }
  .contact-label { width: 52px; font-size: 12px; }
  .contact-value { font-size: 15px; word-break: break-all; }

  .contact-form {
    width: 100%;
    padding: 22px 16px 20px;
    margin-top: 26px;
  }
  .cf-title { font-size: 18px; margin-bottom: 18px; }
  .cf-row { grid-template-columns: 1fr; }
  .cf-field { margin-bottom: 16px; }
  .cf-label { font-size: 12px; margin-bottom: 7px; }
  /* 16px 以上可避免 iOS 聚焦时页面自动放大 */
  .cf-field input,
  .cf-field select,
  .cf-field textarea { font-size: 16px; padding: 12px 12px; }
  .cf-foot { gap: 14px; }
  .cf-submit { width: 100%; padding: 15px 0; letter-spacing: .12em; }
  .cf-status { font-size: 13px; }

  /* ---------- 书籍详情弹层 ---------- */
  .book-modal { padding: 10px; align-items: flex-start; }
  .flipbook {
    width: 100%;
    max-height: calc(100dvh - 20px);
    flex-direction: column;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
  }
  .fb-left { flex: none; padding: 18px; }
  .fb-cover { max-width: 210px; margin: 0 auto; }
  .fb-right { padding: 22px 18px 26px; overflow-y: visible; }
  .md-title { font-size: 22px; }
  .md-sub { font-size: 12px; }
  .md-body p { font-size: 14px; line-height: 1.95; margin-bottom: 16px; }
  .book-close { top: 12px; right: 12px; width: 38px; height: 38px; font-size: 22px; }

  /* ---------- 案例查看器（第二界面） ---------- */
  .cv-bar { padding: 12px 14px; }
  .cv-close {
    padding: 10px 18px;
    font-size: 13px;
    letter-spacing: .12em;
  }
  .cv-scroll {
    padding: 56px 8px 96px;      /* 底部留出返回栏空间 */
    -webkit-overflow-scrolling: touch;
  }
  .cv-scroll img { width: 100%; box-shadow: 0 12px 30px rgba(0, 0, 0, .12); }
  .cv-foot { display: flex; }
  .case-end { display: block; }
}

/* ---------- 小屏手机（≤420px）微调 ---------- */
@media (max-width: 420px) {
  .logo-img { height: 24px !important; }
  .panel { padding: 18px 13px 34px; }
  .panel-title { font-size: 21px; }
  .about-h1 { font-size: 20px; }
  .about-sub { font-size: 14px; }
  .contact-lead { font-size: 18px; }
  .bookshelf { gap: 20px; }
  .home-art { padding: 9px; }
}

/* ---------- 触屏设备：去掉依赖 hover 的效果 ---------- */
@media (hover: none) {
  .work-card:hover .work-frame { transform: none; }
  .work-card:hover .overlay { opacity: 0; }
  .work-card:active .work-frame { transform: scale(.985); }
  .book3d:hover { transform: none; }
}