:root {
  --bg: #050816;
  --bg-alt: #0f172a;
  --surface: #111827;
  --surface-alt: #020617;
  --accent: #38bdf8;
  --accent-soft: rgba(56, 189, 248, 0.15);
  --text: #e5e7eb;
  --text-muted: #9ca3af;
  --border: #1f2937;
  --radius-lg: 18px;
  --radius-md: 12px;
  --shadow-soft: 0 18px 45px rgba(0, 0, 0, 0.6);
}

/* Reset & base */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
}

body {
  font-family: "Inter", "Noto Sans TC", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: radial-gradient(circle at top, #020617 0, #020617 40%, #000 100%);
  color: var(--text);
  line-height: 1.6;
}

/* Layout */
.container {
  width: 100%;
  max-width: 1040px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: linear-gradient(to bottom, rgba(15, 23, 42, 0.96), rgba(15, 23, 42, 0.9));
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(31, 41, 55, 0.9);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  flex-direction: column;
  text-decoration: none;
}

.logo-title {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #e5e7eb;
}

.logo-subtitle {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Nav */
.site-nav {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.nav-link {
  position: relative;
  font-size: 0.9rem;
  text-decoration: none;
  color: var(--text-muted);
  padding: 0.35rem 0.3rem;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0.3rem;
  right: 0.3rem;
  bottom: -0.25rem;
  height: 2px;
  border-radius: 999px;
  transform-origin: center;
  transform: scaleX(0);
  background: linear-gradient(90deg, #38bdf8, #a855f7);
  transition: transform 0.18s ease-out;
}

.nav-link:hover {
  color: #f9fafb;
}

.nav-link:hover::after,
.nav-link.active::after {
  transform: scaleX(1);
}

.nav-link.active {
  color: #f9fafb;
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  border-radius: 999px;
  background: #e5e7eb;
}

/* Hero */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background-size: cover;
  background-position: 43% center;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.35), transparent 55%),
              radial-gradient(circle at bottom right, rgba(147, 51, 234, 0.4), transparent 60%),
              rgba(15, 23, 42, 0.381);
}

.hero-content {
  position: relative;
  z-index: 1;
  padding: 4.5rem 0 4rem;
}

.hero h1 {
  font-size: clamp(2.2rem, 4vw, 3rem);
  margin-bottom: 0.75rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}

.hero p {
  max-width: 540px;
  color: #e5e7eb;
  font-size: 0.98rem;
  margin-bottom: 1.8rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
}

@media (max-width: 640px) {
  .hero-content {
    padding-left: 1.5rem;
    padding-right: 1.5rem;
    text-align: center;
  }

  .hero h1 {
    text-align: center;
  }

  .hero p {
    margin-left: auto;
    margin-right: auto;
    text-align: center;
  }

  .hero-actions {
    justify-content: center;
  }
}

@media (min-width: 641px) and (max-width: 1024px) and (orientation: portrait) {
  .hero-content {
    padding-left: 2.5rem;
    padding-right: 2.5rem;
    text-align: center;
  }

  .hero h1 {
    text-align: center;
  }

  .hero p {
    margin-left: auto;
    margin-right: auto;
    text-align: center;
  }

  .hero-actions {
    justify-content: center;
  }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.55rem 1.2rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease, border-color 0.12s ease;
}

.btn-primary {
  background: linear-gradient(90deg, #38bdf8, #a855f7);
  color: #0b1120;
  box-shadow: 0 14px 40px rgba(56, 189, 248, 0.45);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 55px rgba(56, 189, 248, 0.6);
}

.btn-outline {
  border-color: rgba(148, 163, 184, 0.9);
  color: #e5e7eb;
  background: rgba(15, 23, 42, 0.7);
}

.btn-outline:hover {
  background: rgba(15, 23, 42, 0.95);
}

/* Sections */
.section {
  padding: 3.5rem 0;
}

.section-alt {
  background: radial-gradient(circle at top, #020617 0, #020617 35%, #020617 100%);
}

.section-title {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
}

/* Grid helpers */
.grid-2 {
  display: grid;
  grid-template-columns: minmax(0, 2fr) minmax(0, 1.3fr);
  gap: 2rem;
  align-items: flex-start;
}

/* Cards */
.card {
  background: rgba(15, 23, 42, 0.95);
  border-radius: var(--radius-lg);
  padding: 1.4rem 1.5rem;
  border: 1px solid rgba(31, 41, 55, 0.9);
  box-shadow: var(--shadow-soft);
}

.highlight-card {
  background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.2), rgba(15, 23, 42, 0.96));
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  font-size: 0.75rem;
  background: var(--accent-soft);
  color: #e0f2fe;
  margin-right: 0.25rem;
  margin-top: 0.25rem;
}

/* Card grid */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.4rem;
}

.card-link {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  text-decoration: none;
  color: inherit;
  background: rgba(15, 23, 42, 0.95);
}

.card-link:hover {
  border-color: rgba(56, 189, 248, 0.7);
  box-shadow: 0 16px 45px rgba(56, 189, 248, 0.35);
}

.card-link-text {
  font-size: 0.83rem;
  color: var(--accent);
}

/* Page hero */
.page-hero {
  padding: 2.6rem 0 1.3rem;
  border-bottom: 1px solid rgba(31, 41, 55, 0.8);
  background: radial-gradient(circle at top left, rgba(56, 189, 248, 0.2), rgba(15, 23, 42, 0.95));
}

.page-hero h1 {
  margin: 0 0 0.4rem;
}

.page-hero p {
  margin: 0;
  color: var(--text-muted);
}

/* Advisor */
.advisor-layout {
  align-items: flex-start;
}

.advisor-layout img {
  width: 100%;
  height: auto;
  display: block;
  max-width: 700px;
}

.advisor-photo {
  width: 100%;
  height: auto;
  /* max-width: 280px;
  border-radius: 999px;
  border: 2px solid rgba(56, 189, 248, 0.4);
  box-shadow: var(--shadow-soft);
  object-fit: cover; */
}

/* Timeline */
.timeline-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.timeline-list li {
  position: relative;
  padding-left: 1.2rem;
  margin-bottom: 0.4rem;
  font-size: 0.92rem;
}

.timeline-list li::before {
  content: "";
  position: absolute;
  left: 0.1rem;
  top: 0.55rem;
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: var(--accent);
}

/* Publication list */
.pub-list {
  padding-left: 1.1rem;
}

.pub-list li {
  margin-bottom: 0.6rem;
}

/* Tables */
.table-scroll {
  width: 100%;
  overflow-x: auto;
}

.table {
  border-collapse: collapse;
  width: 100%;
  min-width: 600px;
  font-size: 0.86rem;
}

.table th,
.table td {
  border: 1px solid rgba(55, 65, 81, 0.9);
  padding: 0.4rem 0.6rem;
}

.table th {
  background: rgba(15, 23, 42, 0.96);
}

/* Members */
.member-year {
  margin-top: 1.8rem;
  margin-bottom: 0.65rem;
  font-size: 1.1rem;
}

.member-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
  padding-bottom: 1rem;
}

.member-card {
  background: rgba(15, 23, 42, 0.96);
  border-radius: var(--radius-md);
  border: 1px solid rgba(31, 41, 55, 0.9);
  padding: 0.75rem;
  display: flex;           /* 啟用 Flexbox 佈局 */
  flex-direction: column;  /* 讓內容保持由上而下排列 (如果是左右排列則不用加這行) */
  justify-content: center; /* 垂直置中 (主軸對齊) */
  align-items: center;     /* 水平置中 (交叉軸對齊) */
  text-align: center;
}

.member-card img {
  width: 100%;
  max-width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 999px;
  margin-bottom: 0.5rem;
}

.member-info h3 {
  margin: 0;
  font-size: 0.98rem;
}

.member-role {
  margin: 0.15rem 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Courses */
.course-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.course-list li {
  padding: 0.45rem 0;
  border-bottom: 1px dashed rgba(31, 41, 55, 0.7);
  font-size: 0.95rem;
}

.course-list a {
  color: var(--accent);
  text-decoration: none;
}

.course-list a:hover {
  text-decoration: underline;
}

/* Research projects */
.project {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
  gap: 1.4rem;
  margin-bottom: 2rem;
  align-items: center;
  background-color: rgba(201, 199, 199, 0.173);
  padding: 1.4rem 1.5rem;
  border-radius: var(--radius-lg);
}

.project-media img {
  width: 100%;
  /* border-radius: var(--radius-md); */
  border: 1px solid rgba(31, 41, 55, 0.9);
  box-shadow: var(--shadow-soft);
  object-fit: cover;
  margin-top: 0.8rem;
}

.project-compact {
  background: rgba(15, 23, 42, 0.96);
  border-radius: var(--radius-lg);
  padding: 1.3rem 1.4rem;
  border: 1px solid rgba(31, 41, 55, 0.9);
  margin-bottom: 1rem;
}

.project-figure {
  width: 100%;
  max-width: 100%;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.project-caption {
  font-size: 0.88rem;
  color: #aaa;
  text-align: center;
  line-height: 1.3;
}

.muted {
  color: var(--text-muted);
  font-size: 0.88rem;
  display: block;
  line-height: 1.5;
}

/* Footer */
.site-footer {
  border-top: 1px solid rgba(31, 41, 55, 0.9);
  background: rgba(15, 23, 42, 0.98);
  padding: 1.6rem 0 1.3rem;
  margin-top: 2rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 1.2rem;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
}

.footer-divider {
  opacity: 0.6;
}

/* Responsive */
@media (max-width: 768px) {
  .site-nav {
    position: absolute;
    right: 1.5rem;
    top: 64px;
    flex-direction: column;
    align-items: flex-start;
    padding: 0.6rem 0.9rem;
    background: rgba(15, 23, 42, 0.98);
    border-radius: 0.75rem;
    border: 1px solid rgba(31, 41, 55, 0.9);
    display: none;
  }

  .site-nav.open {
    display: flex;
  }

  .nav-toggle {
    display: flex;
  }

  .hero {
    min-height: 60vh;
  }

  .hero-content {
    padding: 3.2rem 0 3rem;
  }

  .grid-2,
  .project,
  .project-list {
    grid-template-columns: minmax(0, 1fr);
  }

  .advisor-photo {
    max-width: 220px;
    margin-bottom: 1rem;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}