/* =========================================================
   CSS Development Lab 05
   Equal Height Product Cards
   ========================================================= */

:root {
  --page-max: 1200px;
  --text: #171717;
  --muted: #686868;
  --line: #e7e7e1;
  --surface: #ffffff;
  --soft: #f5f5f1;
  --radius: 20px;
  --shadow: 0 18px 44px rgba(0, 0, 0, 0.07);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  color: var(--text);
  background: var(--surface);
  font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  line-height: 1.65;
}

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

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

.page-wrap {
  width: min(calc(100% - 40px), var(--page-max));
  margin-inline: auto;
}

.eyebrow {
  margin: 0 0 14px;
  color: #858585;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.15em;
}

.intro {
  padding: clamp(72px, 10vw, 130px) 0 clamp(58px, 8vw, 90px);
  background:
    radial-gradient(circle at 86% 14%, rgba(0, 0, 0, 0.05), transparent 27%),
    linear-gradient(180deg, #fafaf8 0%, #f3f3ef 100%);
}

.intro-inner {
  max-width: 980px;
}

.intro h1,
.section-head h2,
.explain-copy h2,
.compare-head h2 {
  margin: 0;
  line-height: 1.04;
  letter-spacing: -0.045em;
}

.intro h1 {
  font-size: clamp(2.8rem, 7vw, 6rem);
}

.intro-desc {
  max-width: 780px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.7vw, 1.18rem);
}

.lab {
  padding: clamp(80px, 10vw, 130px) 0;
}

.section-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 0.78fr);
  align-items: end;
  gap: clamp(28px, 6vw, 80px);
}

.section-head h2,
.explain-copy h2,
.compare-head h2 {
  font-size: clamp(2rem, 4.5vw, 4.5rem);
}

.section-head > p,
.explain-copy > p {
  margin: 0;
  color: var(--muted);
}

/* ---------- Outer Grid ---------- */

.product-grid {
  margin-top: clamp(38px, 6vw, 60px);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: clamp(16px, 2.4vw, 24px);
  align-items: stretch;
}

/* ---------- Card ---------- */

.product-card {
  min-width: 0;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  transition:
    transform 200ms ease,
    box-shadow 200ms ease,
    border-color 200ms ease;
}

.product-card:hover {
  transform: translateY(-4px);
  border-color: #d4d4ce;
  box-shadow: var(--shadow);
}

.product-media {
  aspect-ratio: 4 / 3;
  overflow: hidden;
  background: #ddddda;
}

.product-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/*
 * 核心之一：
 * body 使用 flex: 1 吃掉卡片中图片以下的全部剩余高度。
 */
.product-body {
  flex: 1;
  padding: 24px;
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.product-category {
  margin: 0 0 10px;
  color: #898989;
  font-size: 0.74rem;
  font-weight: 800;
  letter-spacing: 0.1em;
}

.product-card h3 {
  margin: 0;
  font-size: clamp(1.2rem, 2vw, 1.55rem);
  line-height: 1.22;
  letter-spacing: -0.025em;
}

.product-desc {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.product-tags {
  margin: 20px 0 24px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
}

.product-tags li {
  padding: 6px 10px;
  border-radius: 999px;
  background: var(--soft);
  color: #555;
  font-size: 0.78rem;
  font-weight: 650;
}

/*
 * 核心之二：
 * margin-top: auto 把按钮推到 product-body 底部。
 */
.product-link {
  margin-top: auto;
  padding-top: 6px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.92rem;
  font-weight: 750;
}

.product-link span {
  transition: transform 180ms ease;
}

.product-link:hover span {
  transform: translateX(4px);
}

/* ---------- Explanation ---------- */

.explain {
  padding: 0 0 clamp(90px, 11vw, 140px);
}

.explain-grid {
  padding: clamp(30px, 6vw, 64px);
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1.1fr);
  align-items: center;
  gap: clamp(34px, 7vw, 90px);
  border-radius: 28px;
  background: var(--soft);
}

.explain-copy > p {
  margin-top: 22px;
}

.code-card {
  min-width: 0;
  overflow-x: auto;
  border-radius: 18px;
  background: #181818;
}

.code-card pre {
  margin: 0;
  padding: clamp(22px, 4vw, 34px);
}

.code-card code {
  color: #f2f2f2;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: clamp(0.82rem, 1.5vw, 0.96rem);
  line-height: 1.75;
}

/* ---------- Compare ---------- */

.compare {
  padding: 0 0 clamp(90px, 12vw, 150px);
}

.compare-head {
  max-width: 760px;
}

.compare-grid {
  margin-top: 38px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.compare-grid article {
  min-height: 230px;
  padding: 26px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: 18px;
}

.compare-grid span {
  color: #999;
  font-size: 0.78rem;
  font-weight: 800;
}

.compare-grid h3 {
  margin: auto 0 10px;
  font-size: 1.3rem;
}

.compare-grid p {
  margin: 0;
  color: var(--muted);
  font-size: 0.93rem;
}

/* ---------- Responsive ---------- */

@media (max-width: 820px) {
  .section-head,
  .explain-grid {
    grid-template-columns: 1fr;
  }

  .compare-grid {
    grid-template-columns: 1fr;
  }

  .compare-grid article {
    min-height: 190px;
  }
}

@media (max-width: 640px) {
  .page-wrap {
    width: calc(100% - 28px);
  }

  .product-body {
    padding: 20px;
  }

  .explain-grid {
    padding: 24px;
  }
}

:focus-visible {
  outline: 2px solid #171717;
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}