/* Ivy AI 學習站：共用樣式（宣紙、墨色、青綠、朱砂） */
:root {
  --paper: #f4efe3; --paper2: #ebe3d1; --card: #fbf8f1; --ink: #1f2a2c; --ink2: #4a5654; --muted: #6d7774; --line: #d8ccb2;
  --azurite: #2d6a8a; --malachite: #3f8f6f; --ochre: #b7793f; --cinnabar: #b8412f; --gold: #c9973a;
  --serif: "Noto Serif TC", "Songti TC", "PMingLiU", serif;
  --sans: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, sans-serif;
  --wrap: 1120px;
  --r: 16px;
  --shadow: 0 10px 30px rgba(31, 42, 44, .10);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0; color: var(--ink); font-family: var(--sans); font-size: 17px; line-height: 1.8;
  background: var(--paper);
  background-image: radial-gradient(rgba(120, 100, 60, .05) 1px, transparent 1px), radial-gradient(rgba(120, 100, 60, .04) 1px, transparent 1px);
  background-size: 22px 22px, 37px 37px;
  background-position: 0 0, 11px 7px;
}
img { max-width: 100%; display: block; }
a { color: var(--azurite); }
h1, h2, h3 { font-family: var(--serif); line-height: 1.3; margin: 0; text-wrap: balance; }
p { margin: 0 0 12px; }
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 20px; }

/* 導覽列 */
.nav { position: sticky; top: 0; z-index: 20; background: rgba(244, 239, 227, .9); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.nav .wrap { display: flex; align-items: center; gap: 18px; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; font-family: var(--serif); font-weight: 900; font-size: 1.1rem; color: var(--ink); text-decoration: none; white-space: nowrap; }
.brand i { width: 32px; height: 32px; border-radius: 9px; display: grid; place-items: center; background: var(--cinnabar); color: #fff8ee; font-style: normal; font-size: .95rem; }
.nav ul { list-style: none; display: flex; gap: 4px; margin: 0 0 0 auto; padding: 0; }
.nav ul a { display: block; padding: 6px 12px; border-radius: 999px; color: var(--ink2); text-decoration: none; font-weight: 700; font-size: .92rem; }
.nav ul a:hover { background: var(--paper2); color: var(--ink); }
.nav .cta { margin-left: 4px; }
@media (max-width: 860px) { .nav ul { display: none; } .nav .cta { margin-left: auto; } }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 22px; border-radius: 12px; font-weight: 700; text-decoration: none; border: 1.5px solid var(--ink); color: var(--ink); background: var(--card); transition: transform .15s, box-shadow .15s; }
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow); }
.btn.pri { background: var(--cinnabar); border-color: var(--cinnabar); color: #fff8ee; }
.btn.sm { padding: 7px 14px; font-size: .9rem; border-radius: 999px; }
.btn.big { font-family: var(--serif); font-size: 1.15rem; letter-spacing: .08em; padding: 14px 28px; }

.kicker { font-size: .85rem; font-weight: 700; letter-spacing: .14em; color: var(--azurite); margin: 0 0 8px; }
.sec { padding: 72px 0; }
.sec.alt { background: rgba(235, 227, 209, .55); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.sec-head { max-width: 720px; margin-bottom: 32px; }
.sec-head h2 { font-size: clamp(1.7rem, 4vw, 2.4rem); font-weight: 900; margin-bottom: 10px; }
.sec-head p { color: var(--ink2); }
.seal-mark { display: inline-block; border: 2.5px double var(--cinnabar); color: var(--cinnabar); font-family: var(--serif); font-weight: 900; padding: 0 8px; border-radius: 4px; transform: rotate(-4deg); font-size: .82rem; margin-left: 6px; vertical-align: middle; }

.chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0 24px; padding: 0; list-style: none; }
.chips li { border: 1px solid var(--line); background: var(--card); border-radius: 999px; padding: 4px 14px; font-weight: 700; font-size: .9rem; color: var(--ink2); }
.chips b { color: var(--cinnabar); font-family: var(--serif); }

.grid { display: grid; gap: 18px; }
.g2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.g3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.g4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
@media (max-width: 960px) { .g4 { grid-template-columns: repeat(2, minmax(0, 1fr)); } .g3 { grid-template-columns: 1fr; } }
@media (max-width: 640px) { .g2, .g4 { grid-template-columns: 1fr; } }

.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--r); padding: 22px; box-shadow: 0 2px 0 rgba(31, 42, 44, .03); min-width: 0; }
.card h3 { font-size: 1.2rem; margin-bottom: 8px; }
.card p { color: var(--ink2); margin: 0; }
.num { font-family: var(--serif); font-weight: 900; color: var(--cinnabar); font-size: 1.6rem; line-height: 1; margin-bottom: 10px; display: block; }

.shot { border-radius: 14px; overflow: hidden; border: 1px solid var(--line); background: var(--paper2); box-shadow: var(--shadow); }
.shot img { width: 100%; height: auto; aspect-ratio: 16 / 9; object-fit: cover; }

.foot { padding: 40px 0 56px; color: var(--muted); font-size: .88rem; border-top: 1px solid var(--line); }
.foot .wrap { display: flex; flex-wrap: wrap; gap: 8px 24px; justify-content: space-between; }

details.faq { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 14px 18px; margin-bottom: 10px; }
details.faq summary { cursor: pointer; font-weight: 700; list-style: none; display: flex; justify-content: space-between; gap: 12px; }
details.faq summary::after { content: "＋"; color: var(--cinnabar); font-weight: 900; }
details.faq[open] summary::after { content: "－"; }
details.faq p { margin: 10px 0 0; color: var(--ink2); }

table.plan { width: 100%; border-collapse: collapse; background: var(--card); border: 1px solid var(--line); border-radius: 12px; overflow: hidden; }
table.plan th, table.plan td { padding: 12px 16px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
table.plan th { background: var(--paper2); font-family: var(--serif); white-space: nowrap; }
table.plan tr:last-child td { border-bottom: 0; }
.tbl { overflow-x: auto; }

:focus-visible { outline: 3px solid var(--gold); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) { * { transition: none !important; scroll-behavior: auto !important; } }