/**
 * 全站主样式 — 401k Calculator
 * 设计：Mobile-First、高对比、大触控目标（≥44px）
 */

:root {
  /* 主色：偏深蓝金融感，WCAG 对比友好 */
  --color-bg: #f4f7fb;
  --color-surface: #ffffff;
  --color-text: #0f172a;
  --color-text-muted: #475569;
  --color-primary: #0c4a6e;
  --color-primary-hover: #075985;
  --color-accent: #059669;
  --color-accent-soft: #d1fae5;
  --color-border: #e2e8f0;
  --color-warning-bg: #fffbeb;
  --color-warning-border: #f59e0b;
  --font-sans: "Source Sans 3", "Segoe UI", system-ui, sans-serif;
  --font-display: "DM Sans", "Source Sans 3", system-ui, sans-serif;
  --radius: 12px;
  --radius-lg: 16px;
  --shadow: 0 4px 24px rgba(15, 23, 42, 0.08);
  --shadow-hover: 0 8px 32px rgba(15, 23, 42, 0.12);
  --space: 1rem;
  --touch-min: 44px;

  /* 全站宽度：移动端全宽 + 安全区；PC 常见 1200px 壳层（Bootstrap xl / 多数落地页区间） */
  --layout-shell-max: 75rem; /* 1200px：PC 常见内容壳，与 Bootstrap .container-xl 等同级 */
  --layout-gutter-x: clamp(1rem, 4.2vw, 1.75rem); /* 移动端≥16px 量级边距，随视口略增 */
  --layout-gutter-header-y: 1rem;
  /* 正文 / 计算器主栏：与顶栏同属 .wrap 壳层内居中，数值与面包屑一致 */
  --layout-content-max: 48rem; /* ~768px：窄屏单列阅读 */
}

@media (min-width: 768px) {
  :root {
    /* ~960px：双列表单、图表与长文共用，避免壳层 1200px 内主栏过窄 */
    --layout-content-max: 60rem;
  }
}

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

html {
  scroll-behavior: smooth;
  /* 避免极窄屏下子元素撑出横向滚动条（clip 优于 hidden，不阻断 position:sticky 等） */
  overflow-x: clip;
}

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  /* 文本与长数字在窄屏换行，避免撑破布局 */
  overflow-wrap: anywhere;
  word-wrap: break-word;
}

/* 排版 */
h1,
h2,
h3 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(1.75rem, 5vw, 2.25rem);
  margin: 0 0 var(--space);
}

h2 {
  font-size: clamp(1.35rem, 4vw, 1.6rem);
  margin: 2rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-primary);
}

h3 {
  font-size: 1.15rem;
  margin: 1.25rem 0 0.5rem;
}

p {
  margin: 0 0 1rem;
}

a {
  color: var(--color-primary);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

a:hover {
  color: var(--color-primary-hover);
}

a:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

/* 布局容器：与顶栏/页脚同一套水平边距（含刘海屏 safe-area） */
.wrap {
  width: 100%;
  max-width: var(--layout-shell-max);
  margin-left: auto;
  margin-right: auto;
  padding-top: 0;
  padding-bottom: 3rem;
  padding-left: max(var(--layout-gutter-x), env(safe-area-inset-left, 0px));
  padding-right: max(var(--layout-gutter-x), env(safe-area-inset-right, 0px));
  box-sizing: border-box;
}

/* 顶栏：背景全宽；水平内边距仅由内部 .wrap 统一处理（含 safe-area），避免重复缩进 */
.site-header {
  background: linear-gradient(135deg, #0c4a6e 0%, #164e63 100%);
  color: #fff;
  padding-top: var(--layout-gutter-header-y);
  padding-bottom: var(--layout-gutter-header-y);
  box-shadow: var(--shadow);
}

.site-header .wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 0;
}

.logo {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.25rem;
  color: #fff;
  text-decoration: none;
}

.logo:focus-visible {
  outline-color: #fff;
}

.nav-main {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.nav-main a {
  color: #e0f2fe;
  text-decoration: none;
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  min-height: var(--touch-min);
  display: inline-flex;
  align-items: center;
}

.nav-main a:hover,
.nav-main a[aria-current="page"] {
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: var(--touch-min);
  padding: 0.75rem 1.5rem;
  font-family: var(--font-sans);
  font-size: 1.05rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.98);
}

.btn:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-primary:focus-visible {
  outline-color: #fff;
  box-shadow: 0 0 0 1px rgba(12, 74, 110, 0.4);
}

.btn-secondary:focus-visible {
  outline-color: var(--color-primary);
}

.calc-live-region {
  margin-top: 0.35rem;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-hover);
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
  background: #e0f2fe;
}

/* 卡片 */
.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: clamp(1rem, 3vw, 1.5rem);
  box-shadow: var(--shadow);
  margin-bottom: 1.5rem;
  border: 1px solid var(--color-border);
  max-width: 100%;
  min-width: 0;
  box-sizing: border-box;
}

.card--highlight {
  border-left: 4px solid var(--color-accent);
}

/* 表单 */
.form-grid {
  display: grid;
  gap: 1rem;
}

@media (min-width: 640px) {
  .form-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.form-grid .form-group {
  min-width: 0;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.form-group label {
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--color-text);
}

.form-group input[type="number"],
.form-group input[type="text"],
.form-group select {
  width: 100%;
  max-width: 100%;
  min-height: var(--touch-min);
  padding: 0.65rem 0.85rem;
  font-size: 1.0625rem;
  border: 2px solid var(--color-border);
  border-radius: 8px;
  background: #fff;
  color: var(--color-text);
}

.form-group input:focus-visible,
.form-group select:focus-visible {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(12, 74, 110, 0.25);
}

/* 滑块：大触控条 */
input[type="range"] {
  width: 100%;
  min-height: var(--touch-min);
  accent-color: var(--color-primary);
}

.range-value {
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  color: var(--color-primary);
}

/* 结果数字 */
.result-hero {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 800;
  color: var(--color-accent);
  font-variant-numeric: tabular-nums;
}

.result-sub {
  font-size: 1rem;
  color: var(--color-text-muted);
}

/* 免责声明 */
.disclaimer {
  background: var(--color-warning-bg);
  border: 1px solid var(--color-warning-border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  font-size: 0.95rem;
  color: #78350f;
  margin-top: 2rem;
}

.disclaimer strong {
  display: block;
  margin-bottom: 0.35rem;
}

/* 广告容器：不固定高度，无广告时折叠 */
.ad-slot {
  margin: 1.5rem 0;
  min-height: 0;
  text-align: center;
}

.ad-slot:empty {
  display: none;
}

.ad-slot.is-hidden {
  display: none;
}

/* 工具网格（首页） */
.tools-grid {
  display: grid;
  gap: 1rem;
}

@media (min-width: 560px) {
  .tools-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .tools-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.tool-card {
  display: block;
  padding: 1.25rem;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 2px solid var(--color-border);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
  min-height: 120px;
}

.tool-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-hover);
}

.tool-card h3 {
  margin: 0 0 0.5rem;
  color: var(--color-primary);
  font-size: 1.1rem;
}

.tool-card p {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

/* 博客 / 知识库列表 */
.blog-grid {
  display: grid;
  gap: 1.25rem;
}

@media (min-width: 560px) {
  .blog-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .blog-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.blog-card {
  display: flex;
  flex-direction: column;
  padding: 1.25rem 1.35rem;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  border: 2px solid var(--color-border);
  text-decoration: none;
  color: inherit;
  min-height: 140px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.blog-card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-hover);
}

.blog-card__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.08rem;
  margin: 0 0 0.5rem;
  color: var(--color-primary);
}

.blog-card__meta {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.blog-card p:last-child {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  flex: 1;
}

.blog-lead {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
}

.post-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-primary);
  background: #e0f2fe;
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  margin-right: 0.35rem;
}

/* 首页：全站入口导航（多栏链接，强化内链） */
.home-explore {
  border: 2px solid var(--color-primary);
  background: linear-gradient(180deg, #f0f9ff 0%, #ffffff 100%);
}

.home-explore__intro {
  margin: 0 0 1.25rem;
  color: var(--color-text-muted);
}

.home-explore__grid {
  display: grid;
  gap: 1.5rem 2rem;
  grid-template-columns: 1fr;
}

@media (min-width: 700px) {
  .home-explore__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1000px) {
  .home-explore__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.home-explore__col-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
  color: var(--color-primary);
  padding-bottom: 0.35rem;
  border-bottom: 2px solid var(--color-border);
}

.home-explore__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.home-explore__list li {
  margin: 0 0 0.35rem;
}

.home-explore__list a {
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  padding: 0.25rem 0;
  font-weight: 500;
}

.home-explore__list a[aria-current="page"] {
  font-weight: 800;
  color: var(--color-accent);
}

.home-explore__note {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
}

/* 首页 / 博客索引：友情链接（外链）— 与 home-explore 同级视觉权重，避免「只有列表无版面」 */
.card.friendly-links {
  margin-top: 1.5rem;
  border: 2px solid var(--color-primary);
  background: linear-gradient(180deg, #f0f9ff 0%, #ffffff 55%);
  box-shadow: var(--shadow);
}

.friendly-links > h2 {
  margin-top: 0;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-border);
}

.friendly-links__intro {
  margin: 0 0 1.25rem;
  color: var(--color-text-muted);
  font-size: 0.98rem;
}

.friendly-links__grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

.friendly-links__grid > li {
  display: flex;
  min-width: 0;
}

@media (min-width: 560px) {
  .friendly-links__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .friendly-links__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.friendly-links__card {
  display: flex;
  flex-direction: column;
  flex: 1;
  width: 100%;
  gap: 0.35rem;
  min-height: 100%;
  padding: 1.15rem 1.25rem;
  background: var(--color-surface);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
  box-sizing: border-box;
}

.friendly-links__card:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-hover);
}

.friendly-links__card:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.friendly-links__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--color-primary);
}

.friendly-links__host {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  word-break: break-all;
}

/* 面包屑：与 .article-rich 同最大宽度、同水平居中，避免「导航条撑满而正文缩进」 */
.breadcrumb {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-bottom: 1rem;
}

main.wrap > .breadcrumb {
  width: 100%;
  max-width: var(--layout-content-max);
  margin-left: auto;
  margin-right: auto;
  box-sizing: border-box;
}

.breadcrumb a {
  color: var(--color-primary);
}

/* 图表容器 */
.chart-wrap {
  position: relative;
  width: 100%;
  max-width: 100%;
  height: min(360px, 55vh);
  min-height: 200px;
  margin-top: 1rem;
}

.chart-wrap canvas {
  max-width: 100%;
}

.article-rich img {
  max-width: 100%;
  height: auto;
}

/* 页脚：多栏 + 内链 + 免责声明，全站统一 */
.site-footer {
  margin-top: 3rem;
  padding-top: clamp(2rem, 5vw, 3rem);
  padding-bottom: max(2rem, env(safe-area-inset-bottom, 0px));
  background: linear-gradient(180deg, #0f172a 0%, #020617 100%);
  color: #94a3b8;
  font-size: 0.9375rem;
  line-height: 1.55;
}

.site-footer a {
  color: #7dd3fc;
  text-decoration: none;
}

.site-footer a:hover {
  color: #bae6fd;
  text-decoration: underline;
}

.site-footer a:focus-visible {
  outline: 2px solid #7dd3fc;
  outline-offset: 2px;
  border-radius: 2px;
}

.site-footer .wrap {
  max-width: var(--layout-shell-max);
  margin: 0 auto;
  padding-left: max(var(--layout-gutter-x), env(safe-area-inset-left, 0px));
  padding-right: max(var(--layout-gutter-x), env(safe-area-inset-right, 0px));
  padding-bottom: 2rem;
}

.site-footer__grid {
  display: grid;
  gap: 2rem 1.75rem;
  grid-template-columns: 1fr;
  padding-bottom: 2rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid rgba(148, 163, 184, 0.25);
}

@media (min-width: 640px) {
  .site-footer__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .site-footer__grid {
    grid-template-columns: 1.35fr 1fr 1fr 1fr;
    align-items: start;
  }
}

.site-footer__logo {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.15rem;
  color: #f1f5f9;
  display: inline-block;
  margin-bottom: 0.75rem;
}

.site-footer__logo:hover {
  color: #fff;
}

.site-footer__tagline {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.6;
  color: #94a3b8;
  max-width: 28rem;
}

.site-footer__col-title {
  margin: 0 0 1rem;
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #cbd5e1;
}

.site-footer__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-footer__list li {
  margin: 0 0 0.5rem;
}

.site-footer__list a {
  display: inline-flex;
  align-items: center;
  min-height: 2.75rem;
  padding: 0.15rem 0;
  font-size: 0.92rem;
}

.site-footer__bottom {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.site-footer__copyright {
  margin: 0;
  font-size: 0.85rem;
  color: #64748b;
}

.site-footer__disclaimer {
  margin: 0;
  font-size: 0.82rem;
  color: #64748b;
  line-height: 1.5;
}

/* 仅桌面横排时分配 flex 比例；移动端为纵向时若保留 flex-grow，会把两段文字之间撑出巨大空白 */
@media (min-width: 768px) {
  .site-footer__bottom {
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1.25rem 2rem;
  }

  .site-footer__copyright {
    flex: 1 1 16rem;
  }

  .site-footer__disclaimer {
    flex: 2 1 22rem;
  }
}

.site-footer__disclaimer strong {
  color: #94a3b8;
}

/* details/summary 高级选项 */
details.advanced {
  margin-top: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.5rem 1rem;
}

details.advanced summary {
  cursor: pointer;
  font-weight: 600;
  min-height: var(--touch-min);
  display: flex;
  align-items: center;
}

/* 列表链接 */
.link-list {
  padding-left: 1.25rem;
}

.link-list li {
  margin-bottom: 0.5rem;
}

/* 长文 / 工具页：主栏宽度由 --layout-content-max 统一（见 :root） */
.article-rich {
  width: 100%;
  max-width: var(--layout-content-max);
  margin-left: auto;
  margin-right: auto;
  box-sizing: border-box;
}


.article-rich > h2:first-of-type {
  margin-top: 0;
}

.content-callout {
  background: #e0f2fe;
  border-left: 4px solid var(--color-primary);
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  margin: 1.25rem 0;
  font-size: 0.98rem;
}

.dl-def {
  margin: 0 0 1.25rem;
}

.dl-def dt {
  font-weight: 700;
  margin-top: 1rem;
  color: var(--color-text);
}

.dl-def dt:first-child {
  margin-top: 0;
}

.dl-def dd {
  margin: 0.35rem 0 0 0;
  padding-left: 0;
}

.tool-card__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
  margin: 0 0 0.5rem;
  color: var(--color-primary);
}

/* Skip link 可访问性 */
.skip-link {
  position: absolute;
  top: -100px;
  left: max(1rem, env(safe-area-inset-left, 0px));
  z-index: 100;
  padding: 0.75rem 1rem;
  background: var(--color-primary);
  color: #fff;
  border-radius: 8px;
}

.skip-link:focus {
  top: max(1rem, env(safe-area-inset-top, 0px));
}