/* ══════════════════════════════════════════════════════════════
   nickel Hero —— 设计令牌
   浅色暖调 + 暖橙主色 + 浮动白色导航
   ══════════════════════════════════════════════════════════════ */

:root {
  /* 核心色(HSL 源值 → HEX) */
  --nk-background:      hsl(249, 18%, 95%);   /* #f2f1f6 暖白 */
  --nk-foreground:      hsl(240, 10%, 10%);   /* #17171c 近黑 */
  --nk-primary:         hsl( 24, 90%, 55%);   /* #f47b21 暖橙 */
  --nk-primary-fg:      hsl(  0,  0%, 100%);  /* #ffffff */
  --nk-secondary:       hsl(  0,  0%, 100%);  /* #ffffff */
  --nk-secondary-fg:    hsl(240, 10%, 10%);
  --nk-muted:           hsl(249, 18%, 95%);
  --nk-muted-fg:        hsl(240,  5%, 46%);   /* #70707d */
  --nk-border:          hsl(240, 10%, 88%);   /* #dcdce3 */
  --nk-nav:             hsl(  0,  0%, 100%);  /* #ffffff */

  /* Hero 按钮渐变 */
  --nk-hero-from:  hsl( 24, 100%, 72%);       /* #ffb37a */
  --nk-hero-to:    hsl( 18,  98%, 53%);       /* #fa6f1c */

  /* 字体 */
  --nk-font: 'Inter', system-ui, sans-serif;

  /* 圆角 */
  --nk-radius-lg: 8px;
  --nk-radius-xl: 12px;
  --nk-radius-sm: 4px;

  --nk-ease: 200ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ══════════════════════════════════════════════════════════════
   nickel Hero —— 样式
   ══════════════════════════════════════════════════════════════ */

/* ── Inter(6 字重)── */
@font-face { font-family: 'Inter'; src: url('/fonts/nk/Inter-300.woff2') format('woff2'); font-weight: 300; font-display: swap; }
@font-face { font-family: 'Inter'; src: url('/fonts/nk/Inter-400.woff2') format('woff2'); font-weight: 400; font-display: swap; }
@font-face { font-family: 'Inter'; src: url('/fonts/nk/Inter-500.woff2') format('woff2'); font-weight: 500; font-display: swap; }
@font-face { font-family: 'Inter'; src: url('/fonts/nk/Inter-600.woff2') format('woff2'); font-weight: 600; font-display: swap; }
@font-face { font-family: 'Inter'; src: url('/fonts/nk/Inter-700.woff2') format('woff2'); font-weight: 700; font-display: swap; }
@font-face { font-family: 'Inter'; src: url('/fonts/nk/Inter-800.woff2') format('woff2'); font-weight: 800; font-display: swap; }

/* ══ ① 页面 ══ */
.nk-page {
  min-height: 100vh;
  background: var(--nk-background);
  color: var(--nk-foreground);
  font-family: var(--nk-font);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ══ ② 浮动导航栏 ══ */
.nk-nav-wrap {
  width: 100%;
  padding: 16px 24px 0;
}
@media (min-width: 1024px) { .nk-nav-wrap { padding: 16px 32px 0; } }

.nk-nav {
  max-width: 1280px;
  margin: 0 auto;
  background: var(--nk-nav);
  border-radius: var(--nk-radius-xl);
  box-shadow: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  padding: 20px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

/* Logo */
.nk-logo { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--nk-foreground); }
.nk-logo__mark {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: var(--nk-foreground);
  display: inline-flex; align-items: center; justify-content: center;
  flex: 0 0 auto;
}
.nk-logo__mark i {
  width: 12px; height: 12px;
  border-radius: var(--nk-radius-sm);
  background: #fff;
  display: block;
}
.nk-logo__text { font-size: 24px; font-weight: 700; letter-spacing: -0.02em; }

/* 中间链接 */
.nk-nav__links { display: none; align-items: center; gap: 24px; }
@media (min-width: 768px) { .nk-nav__links { display: flex; } }
.nk-nav__link {
  display: inline-flex; align-items: center; gap: 5px;
  font-family: var(--nk-font);
  font-size: 16px; font-weight: 500;
  color: rgba(23, 23, 28, 0.80);
  text-decoration: none;
  background: none; border: 0; padding: 0; cursor: pointer;
  transition: color var(--nk-ease);
}
.nk-nav__link:hover { color: var(--nk-foreground); }
.nk-nav__link svg { width: 14px; height: 14px; }

/* 右侧 */
.nk-nav__right { display: flex; align-items: center; gap: 16px; }
.nk-nav__login {
  display: none;
  font-size: 16px; font-weight: 500;
  color: rgba(23, 23, 28, 0.80);
  text-decoration: none;
  transition: color var(--nk-ease);
}
@media (min-width: 640px) { .nk-nav__login { display: inline; } }
.nk-nav__login:hover { color: var(--nk-foreground); }

/* ══ ③ 按钮变体 ══ */
.nk-btn {
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: var(--nk-radius-lg);
  font-family: var(--nk-font);
  font-size: 18px; font-weight: 500;
  border: 0; cursor: pointer;
  text-decoration: none;
  transition: opacity var(--nk-ease), background var(--nk-ease);
  white-space: nowrap;
}
/* 导航栏里的默认尺寸 */
.nk-btn--sm { font-size: 15px; padding: 10px 20px; }

/* hero 变体:橙色渐变 */
.nk-btn--hero {
  background: linear-gradient(to bottom, var(--nk-hero-from), var(--nk-hero-to));
  color: var(--nk-primary-fg);
}
.nk-btn--hero:hover { opacity: 0.90; }

/* hero-outline 变体:白底 */
.nk-btn--hero-outline {
  background: var(--nk-secondary);
  color: var(--nk-secondary-fg);
}
.nk-btn--hero-outline:hover { background: var(--nk-muted); }

/* size=xl */
.nk-btn--xl { height: 56px; padding: 16px 40px; }

/* ══ ④ Hero ══ */
.nk-hero {
  position: relative;
  overflow: hidden;
  background: var(--nk-background);
  min-height: calc(100vh - 4rem);
}
.nk-hero__inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 40px 24px;
  min-height: calc(100vh - 4rem);
  display: flex; align-items: center;
  width: 100%;
  position: relative; z-index: 10;
}
@media (min-width: 1024px) { .nk-hero__inner { padding-left: 32px; padding-right: 32px; } }

.nk-hero__text { max-width: 576px; }

.nk-h1 {
  margin: 0;
  font-family: var(--nk-font);
  font-size: 48px;
  font-weight: 500;
  letter-spacing: -0.025em;
  line-height: 1.05;
  color: var(--nk-foreground);
}
@media (min-width: 640px) { .nk-h1 { font-size: 60px; } }
@media (min-width: 1024px) { .nk-h1 { font-size: 72px; } }

.nk-sub {
  margin: 24px 0 0;
  font-size: 18px;
  line-height: 1.7;
  color: var(--nk-muted-fg);
  max-width: 576px;
}
@media (min-width: 640px) { .nk-sub { font-size: 20px; } }

.nk-actions {
  margin-top: 40px;
  display: flex; flex-wrap: wrap; gap: 16px;
}

/* 右侧视频 */
.nk-hero__video {
  position: absolute;
  top: 0; right: 0;
  width: 55%; height: 100%;
  display: none;
}
@media (min-width: 1024px) { .nk-hero__video { display: block; } }
.nk-hero__video video {
  width: 100%; height: 100%;
  object-fit: cover;
  border-bottom-left-radius: var(--nk-radius-xl);
}

/* ══ ⑤ 响应式 ══ */
@media (max-width: 1023px) {
  .nk-hero__inner { padding-top: 60px; padding-bottom: 60px; }
}
@media (max-width: 639px) {
  .nk-nav { padding: 16px 20px; }
  .nk-btn--xl { height: 52px; padding: 14px 28px; font-size: 16px; }
  .nk-hero__inner { padding: 40px 20px; }
}

/* ══ ⑥ 无障碍 ══ */
.nk-btn:focus-visible, .nk-nav__link:focus-visible, .nk-nav__login:focus-visible, .nk-logo:focus-visible {
  outline: 2px solid var(--nk-primary); outline-offset: 3px;
}
@media (prefers-reduced-motion: reduce) {
  .nk-btn, .nk-nav__link, .nk-nav__login { transition: none; }
}