/* ============================================================
   CASE STUDY — shared components
   继承 style.css 的 tokens / 字体 / 网格语言
   图片：默认黑白，hover 显色
   ============================================================ */

/* ---------- 通用节奏 ---------- */
.case-section { padding-block: clamp(48px, 7vw, 96px); border-top: 1px solid var(--line); }
.case-section.no-rule { border-top: 0; }

.sec-head {
  display: grid;
  grid-template-columns: auto 1fr auto;
  grid-template-areas: "idx line title";
  align-items: center;
  gap: 18px;
  margin-bottom: clamp(24px, 3.5vw, 44px);
}
.sec-idx { grid-area: idx; font-family: var(--font-mono); font-size: .64rem; color: var(--ink-3); letter-spacing: .1em; }
.sec-name {
  grid-area: title;
  font-family: var(--font-display);
  font-variation-settings: "wdth" 125;
  font-weight: 460;
  font-size: clamp(1.1rem, 2.2vw, 1.5rem);
  letter-spacing: .03em;
  text-transform: uppercase;
  margin: 0;
}
.sec-head .dash-line { grid-area: line; }
@media (max-width: 720px) {
  .sec-head { grid-template-columns: auto 1fr; grid-template-areas: "idx title" "line line"; }
}

.case-lead {
  font-size: clamp(1.1rem, 1.9vw, 1.45rem);
  font-weight: 340;
  line-height: 1.5;
  color: var(--ink);
  max-width: 46ch;
  margin: 0 0 26px;
  text-wrap: pretty;
}
.case-body { font-size: .98rem; line-height: 1.65; color: var(--ink-2); max-width: 62ch; margin: 0 0 18px; }
.case-body strong { color: var(--ink); font-weight: 540; }
.case-cols { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: clamp(24px, 4vw, 56px); }
@media (max-width: 860px) { .case-cols { grid-template-columns: 1fr; } }

/* ---------- ① case hero ---------- */
.case-hero { padding-block: clamp(44px, 7vw, 90px); }
.case-kicker {
  font-family: var(--font-mono);
  font-size: .66rem; letter-spacing: .12em; color: var(--ink-3);
  margin: 0 0 22px;
}
.case-title {
  font-family: var(--font-display);
  font-variation-settings: "wdth" 125;
  font-weight: 470;
  font-size: clamp(2rem, 5vw, 3.5rem);
  line-height: 1.02;
  letter-spacing: .015em;
  text-transform: uppercase;
  margin: 0 0 24px;
  max-width: 18ch;
}
.case-sub {
  font-size: clamp(1rem, 1.7vw, 1.25rem);
  font-weight: 320;
  line-height: 1.5;
  color: var(--ink-2);
  max-width: 52ch;
  margin: 0 0 40px;
}

/* meta 条 */
.case-meta {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}
.case-meta div { background: var(--bg); padding: 16px 18px; }
.case-meta dt {
  font-family: var(--font-mono);
  font-size: .58rem; letter-spacing: .1em; color: var(--ink-3);
  margin: 0 0 7px;
}
.case-meta dd { margin: 0; font-size: .82rem; color: var(--ink); line-height: 1.4; }
@media (max-width: 720px) { .case-meta { grid-template-columns: repeat(2, minmax(0, 1fr)); } }

/* ---------- ② 30 秒速读 ---------- */
.tldr {
  border: 1px solid rgba(244,244,241,.22);
  background: var(--panel);
  padding: clamp(22px, 3vw, 34px);
  position: relative;
}
.tldr-label {
  font-family: var(--font-mono);
  font-size: .6rem; letter-spacing: .12em; color: var(--ink-3);
  margin: 0 0 20px;
  display: flex; align-items: center; gap: 10px;
}
.tldr-label::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.tldr-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: clamp(20px, 3vw, 40px); }
@media (max-width: 860px) { .tldr-grid { grid-template-columns: 1fr; gap: 24px; } }
.tldr h3 {
  font-family: var(--font-mono);
  font-size: .6rem; font-weight: 400; letter-spacing: .1em;
  color: var(--ink-3); margin: 0 0 10px;
}
.tldr ul { list-style: none; margin: 0; padding: 0; }
.tldr li { font-size: .88rem; color: var(--ink-2); line-height: 1.5; margin-bottom: 7px; }
.tldr li strong { color: var(--ink); font-weight: 560; }

/* 指标大数字 */
.stat-row { display: grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); margin-top: 26px; }
.stat { background: var(--bg); padding: 20px 18px; }
.stat b {
  display: block;
  font-family: var(--font-display);
  font-variation-settings: "wdth" 125;
  font-weight: 500;
  font-size: clamp(1.3rem, 2.6vw, 1.9rem);
  letter-spacing: .01em;
  margin-bottom: 6px;
}
.stat span { font-family: var(--font-mono); font-size: .58rem; letter-spacing: .08em; color: var(--ink-3); line-height: 1.4; display: block; }
@media (max-width: 720px) { .stat-row { grid-template-columns: repeat(2, minmax(0,1fr)); } }

/* ---------- 图片：黑白 → hover 显色 ---------- */
.figure { margin: 0 0 clamp(20px, 3vw, 34px); }
.figure-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  background: #0d0f11;
  min-height: 180px;
}
.figure img, .figure video {
  display: block; width: 100%; height: auto;
  filter: grayscale(1) contrast(1.03);
  transition: filter .5s ease, transform .7s cubic-bezier(.2,.7,.2,1);
}
.figure:hover img, .figure:hover video { filter: grayscale(0) contrast(1); transform: scale(1.015); }
/* hero 视频：按素材原始比例完整展示，铺满框、不裁切、不留黑边 */
.figure video.cover-video { width: 100%; height: auto; object-fit: contain; background: #000; }
/* 方形素材：收敛宽度并居中，避免整屏大方块 */
.fig-square { max-width: 720px; margin-inline: auto; }
/* 竖屏手机录屏：收得更窄，否则整排宽度会撑出两千多像素高 */
.fig-phone { max-width: 340px; margin-inline: auto; }
.figure figcaption {
  font-family: var(--font-mono);
  font-size: .6rem; letter-spacing: .05em; color: var(--ink-3);
  margin-top: 10px; line-height: 1.5;
}

/* 占位 */
.ph {
  display: grid; place-items: center;
  min-height: 240px; padding: 24px;
  background:
    linear-gradient(to top right, transparent calc(50% - .5px), var(--line), transparent calc(50% + .5px)),
    linear-gradient(to bottom right, transparent calc(50% - .5px), var(--line), transparent calc(50% + .5px));
  font-family: var(--font-mono); font-size: .6rem; letter-spacing: .08em;
  color: var(--ink-3); text-align: center;
}
.ph.tall { min-height: 420px; }
.ph.short { min-height: 160px; }

/* UI Archive：按素材比例排布，消除空洞 */
.ui-rows { display: flex; flex-direction: column; gap: clamp(14px, 2vw, 22px); }
/* 一排：整幅宽图 */
.ui-full { }
/* 一排：左侧超长图 + 右侧堆叠的竖图 */
.ui-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
  gap: clamp(14px, 2vw, 22px);
  align-items: start;
}
.ui-stack { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: clamp(14px, 2vw, 22px); align-content: start; }
/* 整页滚动截图：锁高 + 内部可滚，避免撑出巨大空洞 */
.fig-scroll .figure-frame {
  height: 100%;
  max-height: 780px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: rgba(244,244,241,.25) transparent;
}
.fig-scroll .figure-frame::-webkit-scrollbar { width: 4px; }
.fig-scroll .figure-frame::-webkit-scrollbar-thumb { background: rgba(244,244,241,.25); }
.fig-scroll:hover img { transform: none; }   /* 滚动时不缩放 */
.ui-split > .fig-scroll { height: 100%; display: flex; flex-direction: column; }
.ui-split > .fig-scroll .figure-frame { flex: 1; min-height: 0; }
/* 竖图并排组 */
.ui-tall-row { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: clamp(14px, 2vw, 22px); }
@media (max-width: 860px) {
  .ui-split { grid-template-columns: 1fr; }
  .ui-tall-row { grid-template-columns: repeat(2, minmax(0,1fr)); }
}

.fig-grid-2 { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: clamp(14px, 2vw, 22px); }
.fig-grid-3 { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: clamp(14px, 2vw, 22px); }
@media (max-width: 860px) { .fig-grid-3 { grid-template-columns: repeat(2, minmax(0,1fr)); } }
@media (max-width: 640px) { .fig-grid-2, .fig-grid-3 { grid-template-columns: 1fr; } }

/* ---------- 手机屏截图流程条 ---------- */
.screens { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: clamp(8px, 1.2vw, 14px); }
@media (max-width: 1024px) { .screens { grid-template-columns: repeat(3, minmax(0,1fr)); } }
@media (max-width: 560px) { .screens { grid-template-columns: repeat(2, minmax(0,1fr)); } }
.screen { margin: 0; }
.screen-frame {
  border: 1px solid var(--line);
  background: #0d0f11;
  overflow: hidden;
  transition: border-color .35s, transform .5s cubic-bezier(.2,.7,.2,1);
}
.screen-frame img {
  display: block; width: 100%; height: auto;
  filter: grayscale(1) contrast(1.02);
  transition: filter .5s ease;
}
.screen:hover .screen-frame { border-color: rgba(244,244,241,.45); transform: translateY(-4px); }
.screen:hover .screen-frame img { filter: grayscale(0) contrast(1); }
.screen figcaption {
  font-family: var(--font-mono); font-size: .54rem; letter-spacing: .04em;
  color: var(--ink-3); margin-top: 9px; line-height: 1.5;
}
.screen figcaption b { color: var(--ink-2); font-weight: 400; }

/* ---------- 大按钮：跳到 visuals ---------- */
.visuals-cta {
  display: flex; align-items: center; justify-content: space-between;
  gap: 24px;
  position: relative; overflow: hidden;
  border: 1px solid rgba(244, 244, 241, .3);
  background: var(--panel);
  padding: clamp(22px, 3.2vw, 34px) clamp(20px, 3vw, 34px);
  transition: background .35s ease, border-color .35s ease;
}
/* 持续掠过的光带 */
.visuals-cta::before {
  content: "";
  position: absolute; top: 0; bottom: 0; width: 45%;
  background: linear-gradient(90deg, transparent, rgba(244,244,241,.10), transparent);
  animation: cta-sweep 3.4s ease-in-out infinite;
  pointer-events: none;
}
@keyframes cta-sweep { from { left: -50%; } to { left: 105%; } }
.visuals-cta:hover { background: var(--ink); border-color: var(--ink); }
.visuals-cta:hover::before { opacity: 0; }
.vc-l, .vc-r { position: relative; z-index: 1; }
.vc-k {
  font-family: var(--font-mono); font-size: .6rem; letter-spacing: .12em;
  color: var(--ink-3); margin: 0 0 10px;
  display: flex; align-items: center; gap: 9px;
  transition: color .35s;
}
.vc-t {
  font-family: var(--font-display);
  font-variation-settings: "wdth" 125;
  font-weight: 470;
  font-size: clamp(1.3rem, 3.4vw, 2.3rem);
  letter-spacing: .02em; text-transform: uppercase;
  margin: 0; line-height: 1;
  transition: color .35s;
}
.vc-r { display: flex; align-items: center; gap: 14px; flex: none; }
.vc-count { font-family: var(--font-mono); font-size: .62rem; letter-spacing: .08em; color: var(--ink-3); transition: color .35s; }
.vc-arrow {
  font-size: 1.5rem; line-height: 1; color: var(--ink);
  transition: transform .35s cubic-bezier(.2,.7,.2,1), color .35s;
}
.visuals-cta:hover .vc-t, .visuals-cta:hover .vc-arrow { color: var(--bg); }
.visuals-cta:hover .vc-k, .visuals-cta:hover .vc-count { color: rgba(8,9,10,.62); }
.visuals-cta:hover .vc-arrow { transform: translateX(10px); }
/* 小圆点脉冲 */
.vc-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--ink); flex: none;
  animation: pulse 2.2s ease-in-out infinite;
}
@media (max-width: 640px) {
  .visuals-cta { flex-direction: column; align-items: flex-start; gap: 18px; }
  .vc-r { align-self: flex-end; }
}

/* ---------- visuals 画廊 ---------- */
.visuals { border-top: 1px solid var(--line); padding-block: clamp(48px, 7vw, 96px); }
.clips { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: clamp(12px, 1.8vw, 20px); }
@media (max-width: 900px) { .clips { grid-template-columns: repeat(2, minmax(0,1fr)); } }
@media (max-width: 560px) { .clips { grid-template-columns: 1fr; } }
.clip { margin: 0; }
.clip-frame {
  position: relative; overflow: hidden;
  border: 1px solid var(--line);
  background: #0a0b0c;
  aspect-ratio: 16 / 10;
  transition: border-color .35s;
}
.clip video {
  width: 100%; height: 100%; object-fit: contain; display: block;
  filter: grayscale(1) contrast(1.02);
  transition: filter .5s ease, transform .7s cubic-bezier(.2,.7,.2,1);
}
.clip:hover .clip-frame { border-color: rgba(244,244,241,.4); }
.clip:hover video { filter: grayscale(0) contrast(1); transform: scale(1.02); }
.clip figcaption {
  font-family: var(--font-mono); font-size: .56rem; letter-spacing: .05em;
  color: var(--ink-3); margin-top: 9px;
}
.clip-n { color: var(--ink-2); }

/* ---------- WHY / HOW / WHAT 结构块 ---------- */
.whw { margin: clamp(22px, 3vw, 34px) 0; }
.whw-row {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: clamp(16px, 3vw, 40px);
  border-top: 1px solid var(--line);
  padding: clamp(20px, 2.6vw, 28px) 0;
}
.whw-row:last-child { border-bottom: 1px solid var(--line); }
.whw-k {
  font-family: var(--font-mono);
  font-size: .68rem; letter-spacing: .12em; color: var(--ink-3);
  padding-top: 3px;
}
.whw-body p { margin: 0 0 12px; font-size: .95rem; line-height: 1.62; color: var(--ink-2); }
.whw-body p:last-child { margin-bottom: 0; }
.whw-body strong { color: var(--ink); font-weight: 560; }
.whw-body ul { margin: 6px 0 12px; padding-left: 18px; }
.whw-body li { font-size: .92rem; line-height: 1.55; color: var(--ink-2); margin-bottom: 5px; }
@media (max-width: 640px) {
  .whw-row { grid-template-columns: 1fr; gap: 8px; }
}

/* ---------- 画廊：统一行高、原始比例、不裁剪 ----------
   每行图片同高，宽度按各自比例自适应 → 紧凑无大空隙，且不变形 */
.gallery {
  display: flex; flex-wrap: wrap;
  gap: clamp(10px, 1.4vw, 16px);
  margin: clamp(20px, 3vw, 30px) 0;
}
.gallery figure { margin: 0; flex: 0 1 auto; min-width: 0; }
.gallery .figure-frame {
  height: var(--gh, clamp(240px, 30vw, 400px));
  min-height: 0; overflow: hidden;
}
.gallery .figure-frame img {
  height: 100%; width: auto; max-width: 86vw;
  display: block;
}
.gallery figcaption { font-size: .58rem; }
.gallery.tall { --gh: clamp(300px, 40vw, 460px); }    /* 手机竖屏 */
.gallery.short { --gh: clamp(170px, 22vw, 280px); }   /* 横版幻灯/示例 */

/* ---------- 点击放大 lightbox（图 + 视频）---------- */
.figure-frame img, .figure-frame video,
.screen-frame img, .clip-frame video { cursor: zoom-in; }

.lightbox {
  position: fixed; inset: 0; z-index: 999;
  display: grid; place-items: center;
  background: rgba(8, 9, 10, .96);
  opacity: 0; pointer-events: none;
  transition: opacity .28s ease;
  padding: 4vh 3vw;
  cursor: zoom-out;
}
.lightbox.open { opacity: 1; pointer-events: auto; }
.lb-stage { display: grid; place-items: center; }
.lb-media {
  max-width: 94vw; max-height: 86vh;
  width: auto; height: auto;
  object-fit: contain;
  border: 1px solid var(--line);
  cursor: default;
  /* 进场：随遮罩淡入时轻微放大，避免瞬间硬切 */
  transform: scale(.965);
  opacity: 0;
  transition: transform .3s cubic-bezier(.2,.7,.2,1), opacity .3s ease;
}
.lightbox.open .lb-media { transform: scale(1); opacity: 1; }
.lb-cap {
  position: absolute; left: 50%; bottom: 3vh; transform: translateX(-50%);
  font-size: .62rem; letter-spacing: .08em; color: var(--ink-2);
  max-width: 80vw; text-align: center; margin: 0;
  pointer-events: none;
}
.lb-x {
  position: absolute; top: 20px; right: 24px;
  background: none; border: 0; cursor: pointer;
  font-family: var(--font-mono);
  font-size: .68rem; letter-spacing: .1em; color: var(--ink-2);
  transition: color .2s;
}
.lb-x:hover { color: var(--ink); }
@media (prefers-reduced-motion: reduce) {
  .lb-media { transition: none; transform: none; opacity: 1; }
}

/* 宽屏（大屏/网站）截图：整幅或两幅 */
.wide-row { display: grid; grid-template-columns: 1fr; gap: clamp(14px, 2vw, 22px); margin: clamp(20px, 3vw, 30px) 0; }
.wide-row.two { grid-template-columns: repeat(2, minmax(0,1fr)); }
@media (max-width: 720px) { .wide-row.two { grid-template-columns: 1fr; } }

/* ---------- View More UI 按钮（跳 Google Drive）---------- */
.drive-btn {
  display: inline-flex; align-items: center; gap: 14px;
  font-family: var(--font-mono); font-size: .72rem; letter-spacing: .1em;
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 13px 22px; margin-top: 6px;
  transition: background .25s, border-color .25s, color .25s;
}
.drive-btn:hover { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.drive-btn .arr { transition: transform .25s cubic-bezier(.2,.7,.2,1); }
.drive-btn:hover .arr { transform: translateX(6px); }

/* ---------- 折叠：中国商业文化补充 ---------- */
.aside-note {
  border-left: 1px solid rgba(244,244,241,.3);
  padding: 4px 0 4px clamp(16px, 2.5vw, 24px);
  margin: clamp(24px, 3.5vw, 40px) 0;
}
.aside-note .decision-k { margin-bottom: 14px; }
.aside-note p { font-size: .92rem; line-height: 1.62; color: var(--ink-2); margin: 0 0 10px; max-width: 60ch; }
.aside-note strong { color: var(--ink); font-weight: 560; }

/* ---------- pull quote（产品哲学）---------- */
.pull {
  margin: clamp(30px, 4vw, 52px) 0;
  padding-left: clamp(16px, 2.5vw, 28px);
  border-left: 1px solid rgba(244,244,241,.4);
}
.pull p {
  font-family: var(--font-display);
  font-variation-settings: "wdth" 112;
  font-weight: 350;
  font-size: clamp(1.15rem, 2.4vw, 1.75rem);
  line-height: 1.35;
  letter-spacing: .005em;
  color: var(--ink);
  margin: 0 0 10px;
  max-width: 30ch;
  text-wrap: balance;
}
.pull cite {
  font-family: var(--font-mono); font-style: normal;
  font-size: .58rem; letter-spacing: .1em; color: var(--ink-3);
}

/* ---------- spec list（memo 五个字段）---------- */
.spec { border-top: 1px solid var(--line); margin: 0; padding: 0; list-style: none; }
.spec > li { border-bottom: 1px solid var(--line); padding: 22px 4px; }
.spec-top { display: flex; align-items: baseline; gap: 16px; margin-bottom: 10px; flex-wrap: wrap; }
.spec-n { font-family: var(--font-mono); font-size: .6rem; color: var(--ink-3); flex: none; width: 34px; }
.spec-name {
  font-family: var(--font-display);
  font-variation-settings: "wdth" 110;
  font-weight: 500; font-size: 1.05rem; letter-spacing: .01em;
  color: var(--ink);
}
.spec-tag { font-family: var(--font-mono); font-size: .56rem; letter-spacing: .08em; color: var(--ink-3); border: 1px solid var(--line); padding: 2px 8px; }
.spec p { margin: 0 0 0 50px; font-size: .9rem; line-height: 1.6; color: var(--ink-2); max-width: 64ch; }
.spec .opts { margin: 10px 0 0 50px; font-family: var(--font-mono); font-size: .6rem; letter-spacing: .06em; color: var(--ink-3); }
@media (max-width: 640px) { .spec p, .spec .opts { margin-left: 0; } }

/* ---------- before/after 修复行：文案 + 对应截图并排 ---------- */
.fix-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, .85fr);
  gap: clamp(24px, 4vw, 56px);
  align-items: center;
  border-top: 1px solid var(--line);
  padding-block: clamp(28px, 4vw, 46px);
}
.fix-row:last-of-type { border-bottom: 1px solid var(--line); }
.fix-copy h4 {
  font-family: var(--font-display);
  font-variation-settings: "wdth" 110;
  font-weight: 520; font-size: clamp(1.05rem, 2vw, 1.35rem);
  margin: 0 0 12px; color: var(--ink); line-height: 1.3;
}
.fix-shots { display: grid; grid-auto-flow: column; gap: 12px; justify-content: start; }
.fix-shots .figure { margin: 0; max-width: 220px; }
@media (max-width: 860px) {
  .fix-row { grid-template-columns: 1fr; }
  .fix-shots { justify-content: center; }
}

/* ---------- 设计决策卡 ---------- */
.decisions { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); }
@media (max-width: 860px) { .decisions { grid-template-columns: 1fr; } }
.decision { background: var(--bg); padding: clamp(20px, 2.6vw, 28px); transition: background .3s; }
.decision:hover { background: var(--panel-hover); }
.decision-k { font-family: var(--font-mono); font-size: .58rem; letter-spacing: .1em; color: var(--ink-3); margin: 0 0 12px; }
.decision h4 {
  font-family: var(--font-display);
  font-variation-settings: "wdth" 110;
  font-weight: 500; font-size: 1rem; letter-spacing: .01em;
  margin: 0 0 10px; color: var(--ink); line-height: 1.35;
}
.decision p { margin: 0; font-size: .87rem; line-height: 1.6; color: var(--ink-2); }

/* ---------- 流程步骤 ---------- */
.flow { margin: 0 0 30px; }
.flow-name { font-family: var(--font-mono); font-size: .6rem; letter-spacing: .1em; color: var(--ink-3); margin: 0 0 12px; }
.flow-steps { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.flow-steps span {
  font-family: var(--font-mono); font-size: .64rem; letter-spacing: .05em;
  border: 1px solid var(--line); padding: 7px 12px; color: var(--ink-2);
  transition: border-color .3s, color .3s;
}
.flow-steps span:hover { border-color: rgba(244,244,241,.5); color: var(--ink); }
.flow-steps i { font-style: normal; color: var(--ink-3); font-family: var(--font-mono); font-size: .64rem; }
.flow-steps span.cut { text-decoration: line-through; opacity: .4; }

/* ---------- before / after 指标 ---------- */
.ba { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); margin-bottom: 20px; }
.ba > div { background: var(--bg); padding: 22px; }
.ba-k { font-family: var(--font-mono); font-size: .58rem; letter-spacing: .1em; color: var(--ink-3); margin: 0 0 12px; }
.ba-v {
  font-family: var(--font-display); font-variation-settings: "wdth" 125;
  font-weight: 480; font-size: clamp(1.4rem, 3vw, 2rem); margin: 0 0 4px; letter-spacing: .01em;
}
.ba-note { font-size: .78rem; color: var(--ink-3); margin: 0; }
.ba .up .ba-v { color: var(--ink); }

/* ---------- 迭代列表 ---------- */
.iter { list-style: none; margin: 0; padding: 0; counter-reset: it; }
.iter > li { border-top: 1px solid var(--line); padding: 20px 4px; display: grid; grid-template-columns: 90px 1fr; gap: 18px; }
.iter > li:last-child { border-bottom: 1px solid var(--line); }
.iter-n { font-family: var(--font-mono); font-size: .6rem; letter-spacing: .08em; color: var(--ink-3); }
.iter h4 { margin: 0 0 8px; font-family: var(--font-display); font-variation-settings: "wdth" 110; font-weight: 500; font-size: .98rem; }
.iter p { margin: 0; font-size: .87rem; line-height: 1.6; color: var(--ink-2); max-width: 60ch; }
@media (max-width: 640px) { .iter > li { grid-template-columns: 1fr; gap: 6px; } }

/* ---------- 案例页脚导航 ---------- */
.case-next { border-top: 1px solid var(--line); }
.case-next .container { padding-block: clamp(40px, 6vw, 72px); }
.next-links { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); }
@media (max-width: 640px) { .next-links { grid-template-columns: 1fr; } }
.next-link { background: var(--bg); padding: clamp(22px, 3vw, 30px); display: block; transition: background .3s; }
.next-link:hover { background: var(--panel-hover); }
.next-k { font-family: var(--font-mono); font-size: .58rem; letter-spacing: .1em; color: var(--ink-3); margin: 0 0 10px; }
.next-t {
  font-family: var(--font-display); font-variation-settings: "wdth" 115;
  font-weight: 480; font-size: clamp(1rem, 2vw, 1.3rem); margin: 0; letter-spacing: .01em;
}
.next-link:hover .next-t { color: #fff; }

/* 返回条 */
.case-back { border-bottom: 1px solid var(--line); }
.case-back .container { padding-block: 14px; }
.case-back a { font-family: var(--font-mono); font-size: .64rem; letter-spacing: .1em; color: var(--ink-3); transition: color .25s; }
.case-back a:hover { color: var(--ink); }