/* ==========================================================================
   IJUN AI - Cyber/Tech Style
   ========================================================================== */
:root {
  /* 深藍色科技風格 (Deep Blue Cyber/Tech Style) */
  --bg-dark: #0a1128;
  --bg-card: rgba(10, 17, 40, 0.7);
  --bg-card-hover: rgba(23, 42, 69, 0.85);
  --border-color: rgba(0, 180, 216, 0.3); /* 霓虹藍邊框 */
  --border-glow: rgba(0, 245, 212, 0.5);
  --text-main: #e2e8f0;
  --text-muted: #94a3b8;
  
  --accent-cyan: #00f5d4;
  --accent-blue: #00b4d8; /* 霓虹藍 */
  --accent-neon: #48cae4;
  --accent-purple: #7209b7;
  --accent-orange: #ff9e00;
  --accent-green: #38b000;
  
  --shadow-glow: 0 8px 32px 0 rgba(0, 180, 216, 0.15); /* 霓虹發光感 */
  --radius: 12px;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Noto Sans TC', sans-serif;
  background-color: var(--bg-dark);
  background-image: 
    radial-gradient(circle at 15% 15%, rgba(0, 180, 216, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 85% 60%, rgba(114, 9, 183, 0.08) 0%, transparent 40%),
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 40px 40px, 40px 40px;
  color: var(--text-main);
  line-height: 1.6;
  padding-bottom: 60px;
  overflow-x: hidden;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-dark);
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-blue);
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header & Navigation */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(10, 17, 40, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.nav-wrapper {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 75px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: #fff;
  font-family: 'Orbitron', 'Noto Sans TC', sans-serif;
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: 1px;
}

.logo-badge {
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-neon));
  color: #fff;
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 0.95rem;
  box-shadow: 0 0 10px rgba(0, 180, 216, 0.4);
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 20px;
  list-style: none;
}

.nav-link {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: var(--transition);
  padding: 6px 12px;
  border-radius: 6px;
}

.nav-link:hover, .nav-link.active {
  color: var(--accent-cyan);
  background: rgba(0, 245, 212, 0.08);
  text-shadow: 0 0 8px rgba(0, 245, 212, 0.4);
}

/* Custom Facebook Pill Button (奕鈞老師風格) */
.yijun-fb-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  background: #176B9E;
  color: #fff;
  text-decoration: none;
  padding: 5px 22px 5px 22px;
  border-radius: 50px;
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 1px;
  box-shadow: 0 0 10px rgba(0, 180, 216, 0.3);
  transition: var(--transition);
  border: 1px solid #4AAFE4;
}

.yijun-fb-btn:hover {
  transform: translateY(-2px) scale(1.03);
  box-shadow: 0 0 15px rgba(0, 180, 216, 0.4);
  background: #1a7ab5;
  color: #fff;
}

.hamburger {
  display: none;
  background: none;
  border: none;
  color: var(--text-main);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Hero Section */
.hero {
  padding: 80px 0 60px;
  text-align: center;
  position: relative;
}

.hero-title {
  font-size: 3.2rem;
  font-weight: 900;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #ffffff 30%, var(--accent-cyan) 70%, var(--accent-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: 2px;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 800px;
  margin: 0 auto 40px;
}

/* Stats bar */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 20px;
  margin-bottom: 40px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  backdrop-filter: blur(10px);
  transition: var(--transition);
}

.stat-card:hover {
  border-color: var(--accent-cyan);
  box-shadow: var(--shadow-glow);
  transform: translateY(-4px) scale(1.02);
}

/* 專屬助手: 邀請講師卡片淡紫光暈 */
.stat-card[href*="invite"]:hover {
  border-color: #B8A4FF;
  box-shadow: 0 0 12px rgba(116, 103, 216, 0.35);
}

.stat-number {
  font-family: 'Orbitron', sans-serif;
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent-cyan);
  margin-bottom: 8px;
  text-shadow: 0 0 10px rgba(0, 245, 212, 0.3);
}

.stat-label {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Section Styles */
.section {
  margin-bottom: 80px;
  scroll-margin-top: 100px;
}

.section-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 30px;
  border-bottom: 1px solid rgba(0, 180, 216, 0.15);
  padding-bottom: 16px;
}

.section-icon {
  width: 42px;
  height: 42px;
  background: linear-gradient(135deg, var(--accent-blue), var(--accent-neon));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: bold;
  font-size: 1.2rem;
  box-shadow: 0 0 15px rgba(0, 180, 216, 0.4);
}

.section-title {
  font-size: 1.8rem;
  font-weight: 700;
  color: #fff;
}

/* Content Cards Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 30px;
  backdrop-filter: blur(12px);
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-cyan);
  box-shadow: 0 8px 30px rgba(0, 180, 216, 0.2);
  transform: translateY(-4px) scale(1.02);
}

.card-tag {
  display: inline-block;
  align-self: flex-start;
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 16px;
}

.tag-cyan { background: rgba(0, 245, 212, 0.15); color: var(--accent-cyan); border: 1px solid rgba(0, 245, 212, 0.3); }
.tag-blue { background: rgba(0, 180, 216, 0.15); color: var(--accent-blue); border: 1px solid rgba(0, 180, 216, 0.3); }
.tag-purple { background: rgba(114, 9, 183, 0.15); color: #c77dff; border: 1px solid rgba(114, 9, 183, 0.3); }
.tag-orange { background: rgba(255, 158, 0, 0.15); color: var(--accent-orange); border: 1px solid rgba(255, 158, 0, 0.3); }
.tag-green { background: rgba(56, 176, 0, 0.15); color: #70e000; border: 1px solid rgba(56, 176, 0, 0.3); }

.card-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: #ffffff;
  margin-bottom: 16px;
}

.card-list {
  list-style: none;
  margin-top: 8px;
}

.card-list li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 12px;
  color: var(--text-main);
  font-size: 1.05rem;
  line-height: 1.6;
}

.card-list li::before {
  content: "▹";
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
  font-weight: bold;
}

.card-list strong {
  color: #ffffff;
}

/* Tool Link Card Styling */
.tool-link-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-top: 16px;
  padding: 12px 20px;
  background: linear-gradient(135deg, rgba(0, 245, 212, 0.15), rgba(0, 180, 216, 0.25));
  border: 1px solid var(--accent-cyan);
  border-radius: 8px;
  color: var(--accent-cyan);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.05rem;
  transition: var(--transition);
}

.tool-link-btn:hover {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
  color: #070c18;
  box-shadow: 0 0 20px rgba(0, 245, 212, 0.5);
  transform: translateY(-2px) scale(1.02);
}

/* Tree Component (Used for experiences/materials placeholder) */
.tree-card {
  grid-column: 1 / -1;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 30px;
  backdrop-filter: blur(12px);
  transition: var(--transition);
}

.tree-card:hover {
  border-color: var(--accent-cyan);
  box-shadow: 0 8px 30px rgba(0, 180, 216, 0.2);
}

/* Footer */
footer {
  margin-top: 80px;
  padding: 40px 0;
  border-top: 1px solid var(--border-color);
  background: rgba(10, 17, 40, 0.95);
  text-align: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.back-to-top {
  background: rgba(0, 180, 216, 0.15);
  color: var(--accent-cyan);
  border: 1px solid var(--border-color);
  padding: 10px 24px;
  border-radius: 24px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  transition: var(--transition);
}

.back-to-top:hover {
  background: var(--accent-blue);
  color: #fff;
  box-shadow: 0 0 15px rgba(0, 180, 216, 0.5);
  transform: translateY(-2px);
}

/* Responsive */
@media (max-width: 768px) {
  .hero-title { font-size: 2.2rem; }
  .hamburger { display: block; }
  .nav-menu {
    display: none;
    position: absolute;
    top: 75px;
    left: 0;
    right: 0;
    background: rgba(10, 17, 40, 0.98);
    flex-direction: column;
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
  }
  .nav-menu.show { display: flex; }
  .cards-grid { grid-template-columns: 1fr; }
}
/* Modal (uX) 򥻼˦ */
.modal { display: none; position: fixed; z-index: 2000; left: 0; top: 0; width: 100%; height: 100%; overflow: auto; background-color: rgba(0,0,0,0.8); backdrop-filter: blur(5px); align-items: center; justify-content: center; }
.modal.show { display: flex !important; }
.modal-content { position: relative; margin: auto; padding: 0; width: 90%; max-width: 900px; border-radius: 12px; overflow: hidden; box-shadow: 0 4px 20px rgba(0,0,0,0.5); background: rgba(10, 17, 40, 0.7); border: 1px solid rgba(0, 180, 216, 0.3); }
.image-modal-content { max-width: 800px; padding: 20px; background: transparent; border: none; box-shadow: none; }
.image-container { display: flex; justify-content: center; align-items: center; }
.cert-modal-img { max-width: 100%; max-height: 75vh; object-fit: contain; border-radius: 8px; box-shadow: 0 0 20px rgba(255,255,255,0.1); }
.close-btn { position: absolute; top: 10px; right: 20px; color: #f1f5f9; font-size: 30px; font-weight: bold; cursor: pointer; z-index: 10; text-shadow: 0 2px 4px rgba(0,0,0,0.5); }
.close-btn:hover, .close-btn:focus { color: #ef4444; text-decoration: none; }