/* ===== Base ===== */
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC",
               "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", Arial, sans-serif;
  color: #111827;
  background: #f8f8f8;
  overflow-x: hidden; /* 防横向滚动 */
}

/* 自适应字号：小屏不小到看不清，大屏不夸张 */
:root{
  --wrap: 1180px;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(17,24,39,.08);
  --border: 1px solid rgba(17,24,39,.08);

  --bg: #f8f8f8;
  --card: #ffffff;
  --muted: #6b7280;
  --primary: #2563eb;
  --primary2:#1d4ed8;

  --fs-1: clamp(18px, 2.2vw, 26px);
  --fs-2: clamp(14px, 1.4vw, 16px);
  --fs-3: clamp(12px, 1.2vw, 14px);
  --gap: clamp(12px, 2.2vw, 18px);
  --pad: clamp(14px, 2.4vw, 22px);
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }

.wrap{
  width: min(var(--wrap), 100% - 32px);
  margin: 0 auto;
}

/* ===== Topbar ===== */
.topbar{
  background: #111827;
  color: #e5e7eb;
  font-size: var(--fs-3);
}
.topbar__inner{
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
}
.topbar__text{ opacity: .9; }
.topbar__nav{ display:flex; gap:10px; flex-wrap: wrap; }
.chip{
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(255,255,255,.10);
}

/* ===== Header ===== */
.header{
  background: var(--card);
  border-bottom: var(--border);
}
.header__inner{
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap);
  padding: 16px 0;
  flex-wrap: wrap; /* 小屏自动换行 */
}
.brand{
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 240px;
}
.brand__logo{
  width: 46px;
  height: 46px;
  border-radius: 10px;
  background: #f3f4f6;
  object-fit: cover;
}
.brand__name{
  font-weight: 800;
  font-size: clamp(16px, 2vw, 20px);
}
.brand__desc{
  font-size: var(--fs-3);
  color: var(--muted);
  margin-top: 2px;
}

.search{
  display: flex;
  gap: 10px;
  width: min(520px, 100%);
}
.search input{
  flex: 1;
  padding: 12px 14px;
  border-radius: 12px;
  border: var(--border);
  outline: none;
  font-size: var(--fs-2);
  background: #fff;
}
.search button{
  padding: 12px 14px;
  border: none;
  border-radius: 12px;
  background: var(--primary);
  color: #fff;
  font-weight: 700;
  cursor: pointer;
}
.search button:hover{ background: var(--primary2); }

/* Nav */
.nav{
  border-top: var(--border);
  background: #fff;
}
.nav__inner{
  display: flex;
  gap: 10px;
  padding: 10px 0;
  overflow: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.nav__inner::-webkit-scrollbar{ display:none; }
.nav__link{
  white-space: nowrap;
  font-size: var(--fs-2);
  padding: 10px 12px;
  border-radius: 999px;
  background: #f3f4f6;
}
.nav__link.is-active{
  background: rgba(37,99,235,.12);
  color: var(--primary2);
  font-weight: 700;
}

/* ===== Layout ===== */
.main{
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
  padding: var(--gap) 0 26px;
}

/* >= 1024px：主内容+侧栏 */
@media (min-width: 1024px){
  .main{
    grid-template-columns: 1.55fr .75fr;
    align-items: start;
  }
}

/* ===== Card ===== */
.card{
  background: var(--card);
  border: var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.card__head{
  padding: var(--pad);
  border-bottom: var(--border);
}
.card__title{
  margin: 0;
  font-size: var(--fs-1);
  line-height: 1.25;
}
.card__sub{
  margin: 10px 0 0;
  color: var(--muted);
  font-size: var(--fs-2);
  line-height: 1.6;
}

/* ===== Calculator Grid ===== */
.grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--gap);
  padding: var(--pad);
}

/* >= 900px：输入区/结果区两列 */
@media (min-width: 900px){
  .grid{
    grid-template-columns: 1fr 1fr;
  }
}

.panel{
  border: var(--border);
  border-radius: 14px;
  padding: var(--pad);
  background: #fff;
}
.panel__title{
  margin: 0 0 12px;
  font-size: clamp(16px, 1.7vw, 18px);
}

/* ===== Form ===== */
.field{ margin-bottom: 14px; }
label{
  display: block;
  font-size: var(--fs-2);
  color: #111827;
  margin-bottom: 8px;
  font-weight: 600;
}
input, select{
  width: 100%;
  padding: 12px 12px;
  border-radius: 12px;
  border: var(--border);
  outline: none;
  font-size: 16px; /* 关键：避免 iOS 自动放大 */
  background: #fff;
}
input:focus, select:focus{
  border-color: rgba(37,99,235,.45);
  box-shadow: 0 0 0 4px rgba(37,99,235,.10);
}
.hint{
  margin-top: 6px;
  font-size: var(--fs-3);
  color: var(--muted);
}

.actions{
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 8px;
}

.btn{
  padding: 12px 14px;
  border-radius: 12px;
  border: var(--border);
  background: #fff;
  cursor: pointer;
  font-weight: 700;
  font-size: var(--fs-2);
}
.btn--primary{
  background: var(--primary);
  color: #fff;
  border: none;
}
.btn--primary:hover{ background: var(--primary2); }

.note{
  margin-top: 12px;
  font-size: var(--fs-3);
  color: var(--muted);
  line-height: 1.7;
}

/* ===== Result KV ===== */
.kv{ display: grid; gap: 10px; }
.kv__row{
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 12px 12px;
  border-radius: 12px;
  background: #f9fafb;
  border: 1px solid rgba(17,24,39,.06);
}
.kv__k{ color: #374151; font-size: var(--fs-2); }
.kv__v{ font-weight: 800; font-size: var(--fs-2); }
.kv__row--strong{
  background: rgba(37,99,235,.08);
  border-color: rgba(37,99,235,.18);
}

/* ===== Sidebar ===== */
.sidebar{ display: grid; gap: var(--gap); }
.prose{
  padding: var(--pad);
  color: #374151;
  font-size: var(--fs-2);
  line-height: 1.8;
}
.list{ padding: 10px 0; }
.list__item{
  display: block;
  padding: 12px var(--pad);
  border-top: var(--border);
  color: #111827;
}
.list__item:hover{ background: #f9fafb; }

.tips{
  margin-top: 14px;
  padding: 12px;
  border-radius: 12px;
  border: var(--border);
  background: #fff;
}
.tips__title{ font-weight: 800; margin-bottom: 8px; }
.tips ul{ margin: 0; padding-left: 18px; color: var(--muted); line-height: 1.7; }

/* ===== Footer ===== */
.footer{
  padding: 22px 0;
  color: #6b7280;
}
.footer__inner{
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 14px;
  flex-wrap: wrap;
}
.footer__brand{
  font-weight: 800;
  color: #111827;
}
.footer__right{
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.footer__right a:hover{ color: #111827; }