/* ===========================================================================
   Custom modern theme for Meng Gu's faculty site.
   Loaded AFTER main.css (HTML5 UP "Stellar"); overrides the template globals
   and adds new components (nav, hero, research cards, publication list).
   =========================================================================== */

:root {
	--accent:        #2a6fb0;   /* primary blue */
	--accent-dark:   #1b4a78;
	--accent-soft:   #eaf2fa;
	--ink:           #23303b;   /* body text */
	--ink-soft:      #5a6b78;   /* secondary text */
	--line:          #e3e8ee;   /* hairlines */
	--bg:            #ffffff;
	--bg-alt:        #f6f8fb;   /* alternating section band */
	--radius:        14px;
	--shadow:        0 6px 24px rgba(26, 50, 84, 0.08);
	--shadow-lift:   0 14px 34px rgba(26, 50, 84, 0.16);
	--maxw:          1080px;
	--serif:         "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
	--sans:          -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* ---- Reset template's dark theme to a clean light page ------------------- */
html { scroll-behavior: smooth; }
html, body { height: auto; }
section[id], .field[id] { scroll-margin-top: 74px; }
body {
	background: var(--bg) !important;
	color: var(--ink);
	font-family: var(--sans);
	font-size: 16.5px;
	line-height: 1.7;
	letter-spacing: 0;
	overflow-x: hidden;
}
body.is-preload * { -webkit-transition: none !important; transition: none !important; }

#wrapper { background: transparent; }
#main { padding: 0; }

h1, h2, h3, h4 { font-family: var(--serif); color: var(--ink); letter-spacing: 0; line-height: 1.25; }
a { color: var(--accent); text-decoration: none; transition: color .15s ease; }
a:hover { color: var(--accent-dark); }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 28px; }

/* ---- Sticky top navigation ---------------------------------------------- */
.site-nav {
	position: sticky; top: 0; z-index: 1000;
	background: rgba(255,255,255,0.92);
	-webkit-backdrop-filter: saturate(180%) blur(10px);
	backdrop-filter: saturate(180%) blur(10px);
	border-bottom: 1px solid var(--line);
}
.site-nav .wrap {
	display: flex; align-items: center; justify-content: space-between;
	height: 62px;
}
.site-nav .brand {
	font-family: var(--serif); font-size: 1.2rem; font-weight: 700;
	color: var(--ink); white-space: nowrap;
}
.site-nav .brand .zh { font-family: STKaiti, "KaiTi", serif; color: var(--ink-soft); margin-left: 8px; font-weight: 400; }
.site-nav ul { list-style: none; display: flex; gap: 26px; margin: 0; padding: 0; }
.site-nav ul a {
	font-family: var(--sans); font-size: .93rem; color: var(--ink-soft);
	font-weight: 600; letter-spacing: .02em; border: 0;
}
.site-nav ul a:hover { color: var(--accent); }
.nav-toggle { display: none; }

/* ---- Hero --------------------------------------------------------------- */
.hero {
	background: radial-gradient(1200px 480px at 78% -8%, var(--accent-soft), transparent 60%), var(--bg);
	padding: 72px 0 60px;
	border-bottom: 1px solid var(--line);
}
.hero .wrap { display: grid; grid-template-columns: 1fr 250px; gap: 48px; align-items: center; }
.hero h1 { font-size: 2.9rem; margin: 0 0 6px; }
.hero h1 .zh { font-family: STKaiti, "KaiTi", serif; font-size: 1.7rem; color: var(--ink-soft); margin-left: 14px; font-weight: 400; }
.hero .role { font-size: 1.15rem; color: var(--accent-dark); font-weight: 600; margin: 0 0 4px; }
.hero .affil { color: var(--ink-soft); margin: 0 0 18px; }
.hero .tagline { font-size: 1.02rem; color: var(--ink); max-width: 64ch; margin: 8px 0 24px; }
.hero .brand-name { font-family: var(--serif); font-size: 2.4rem; margin: 0 0 10px; }
.hero .portrait {
	width: 230px; height: 230px; border-radius: 50%; object-fit: cover;
	box-shadow: var(--shadow-lift); border: 5px solid #fff; justify-self: center;
}

/* ---- Badge / link pills ------------------------------------------------- */
.badge-links { display: flex; flex-wrap: wrap; gap: 12px; }
.badge-links a {
	display: inline-flex; align-items: center; gap: 8px;
	padding: 9px 16px; border-radius: 999px;
	background: #fff; border: 1px solid var(--line); box-shadow: var(--shadow);
	color: var(--ink); font-weight: 600; font-size: .9rem;
}
.badge-links a:hover { color: var(--accent); border-color: var(--accent); transform: translateY(-1px); }
.badge-links a .icon { color: var(--accent); }

/* ---- Generic section ---------------------------------------------------- */
.section { padding: 64px 0; }
.section.alt { background: var(--bg-alt); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.section > .wrap > .eyebrow {
	text-transform: uppercase; letter-spacing: .16em; font-size: .78rem;
	font-weight: 700; color: var(--accent); margin: 0 0 6px;
}
.section h2 { font-size: 2rem; margin: 0 0 22px; }
.section .lead { font-size: 1.06rem; color: var(--ink); max-width: 70ch; }

/* ---- About -------------------------------------------------------------- */
.about p { color: var(--ink); }

/* ---- Research field cards ----------------------------------------------- */
.research-grid {
	display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
	gap: 24px; margin-top: 28px;
}
.research-card {
	display: flex; flex-direction: column; background: #fff;
	border: 1px solid var(--line); border-radius: var(--radius);
	box-shadow: var(--shadow); overflow: hidden;
	transition: transform .18s ease, box-shadow .18s ease;
}
.research-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lift); }
.research-card .thumb { height: 150px; background: var(--accent-soft) center/cover no-repeat; }
.research-card .thumb.placeholder {
	display: flex; align-items: center; justify-content: center;
	color: var(--accent); font-size: 2.4rem;
	background: linear-gradient(135deg, var(--accent-soft), #dceaf6);
}
.research-card .body { padding: 20px 22px 24px; display: flex; flex-direction: column; flex: 1; }
.research-card h3 { font-size: 1.22rem; margin: 0 0 8px; }
.research-card p { color: var(--ink-soft); font-size: .96rem; margin: 0 0 16px; }
.research-card .more { margin-top: auto; font-weight: 600; font-size: .9rem; }
.research-card .more::after { content: " \2192"; }

/* ---- Research detail sections ------------------------------------------- */
.field { padding: 56px 0; border-top: 1px solid var(--line); scroll-margin-top: 70px; }
.field:first-of-type { border-top: 0; }
.field .wrap { display: grid; grid-template-columns: 1.1fr 1fr; gap: 44px; align-items: center; }
.field.flip .wrap { grid-template-columns: 1fr 1.1fr; }
.field.flip .text { order: 2; }
.field .eyebrow { text-transform: uppercase; letter-spacing: .16em; font-size: .76rem; font-weight: 700; color: var(--accent); margin: 0 0 6px; }
.field h2 { font-size: 1.7rem; margin: 0 0 14px; }
.field p { color: var(--ink); }
.field figure { margin: 0; }
.field figure img { width: 100%; height: auto; border-radius: var(--radius); box-shadow: var(--shadow); }
.field .fig-placeholder {
	display: flex; flex-direction: column; align-items: center; justify-content: center;
	min-height: 240px; border-radius: var(--radius);
	background: linear-gradient(135deg, var(--accent-soft), #dceaf6);
	color: var(--accent-dark); text-align: center; padding: 24px; border: 1px dashed #b9d4ee;
}
.field .fig-placeholder .icon { font-size: 2.6rem; margin-bottom: 10px; }
.tool-btn { display: inline-flex; align-items: center; gap: 8px; padding: 10px 18px; border-radius: 999px;
	background: var(--accent); color: #fff; font-weight: 600; font-size: .92rem; box-shadow: var(--shadow); }
.tool-btn:hover { background: var(--accent-dark); color: #fff; transform: translateY(-1px); }

/* selected-papers list within a field */
.paper-list { list-style: none; margin: 18px 0 0; padding: 0; }
.paper-list li { padding: 9px 0; border-top: 1px solid var(--line); font-size: .96rem; }
.paper-list li:first-child { border-top: 0; }
.paper-list .pyear { color: var(--ink-soft); font-variant-numeric: tabular-nums; margin-right: 8px; font-weight: 600; }

/* ---- Full publication list ---------------------------------------------- */
.pub-year { margin: 34px 0 10px; font-size: 1.15rem; color: var(--accent-dark);
	padding-bottom: 6px; border-bottom: 2px solid var(--accent-soft); }
.pub-list { list-style: none; margin: 0; padding: 0; }
.pub-list li { padding: 14px 0; border-bottom: 1px solid var(--line); display: block; }
.pub-list .ptitle { font-weight: 600; color: var(--ink); }
.pub-list .ptitle a { color: var(--ink); }
.pub-list .ptitle a:hover { color: var(--accent); }
.pub-list .pmeta { display: block; color: var(--ink-soft); font-size: .92rem; margin-top: 3px; }
.pub-list .pmeta .pjournal { font-style: italic; }
.pub-list .pmeta b { color: var(--ink); }
.pub-tag {
	display: inline-block; font-size: .68rem; font-weight: 700; text-transform: uppercase;
	letter-spacing: .05em; padding: 2px 8px; border-radius: 999px; margin-left: 8px;
	background: var(--accent-soft); color: var(--accent-dark); vertical-align: middle;
}

/* ---- Footer / contact --------------------------------------------------- */
.site-footer { background: #1b2630; color: #c6d2dd; padding: 54px 0 30px; }
.site-footer h2 { color: #fff; font-size: 1.3rem; margin: 0 0 14px; }
.site-footer a { color: #9ec9f0; }
.site-footer .cols { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; }
.site-footer dt { color: #fff; font-weight: 700; margin-top: 10px; }
.site-footer dd { margin: 0 0 6px; }
.site-footer .copyright { margin-top: 30px; padding-top: 18px; border-top: 1px solid rgba(255,255,255,.12); font-size: .85rem; color: #8a9aa8; }

/* ---- Responsive --------------------------------------------------------- */
@media (max-width: 860px) {
	.hero .wrap { grid-template-columns: 1fr; text-align: center; }
	.hero .portrait { order: -1; width: 170px; height: 170px; }
	.hero .tagline, .hero .badge-links { margin-left: auto; margin-right: auto; }
	.hero .badge-links { justify-content: center; }
	.field .wrap, .field.flip .wrap { grid-template-columns: 1fr; }
	.field figure, .field .text, .field.flip .text { order: 0; }
	.site-footer .cols { grid-template-columns: 1fr; }
}

@media (max-width: 680px) {
	.site-nav ul { display: none; position: absolute; top: 62px; left: 0; right: 0;
		flex-direction: column; gap: 0; background: #fff; border-bottom: 1px solid var(--line); box-shadow: var(--shadow); }
	.site-nav ul.open { display: flex; }
	.site-nav ul li { border-top: 1px solid var(--line); }
	.site-nav ul a { display: block; padding: 14px 28px; }
	.nav-toggle { display: inline-flex; background: none; border: 0; font-size: 1.5rem; color: var(--ink); cursor: pointer; }
	.hero h1 { font-size: 2.2rem; }
	.section, .field { padding: 44px 0; }
}