/* ================================================================
   edu.caistudio.cn — 融合风格 (小蔡不会飞 + 小蔡的创造空间)
   配色：燕麦暖白 #F5F0EB / 鼠尾草绿 #6B8F71 / 暖黑 #3D3D3A
   ================================================================ */

/* ---------- Reset & Base ---------- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background-color: #F5F0EB;
  color: #3D3D3A;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'PingFang SC', sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
body::before {
  content: '';
  position: fixed; top: 0; left: 0; right: 0; bottom: 0;
  background: repeating-linear-gradient(0deg, transparent, transparent 2px, rgba(0,0,0,0.006) 2px, rgba(0,0,0,0.006) 4px),
              repeating-linear-gradient(90deg, transparent, transparent 2px, rgba(0,0,0,0.004) 2px, rgba(0,0,0,0.004) 4px);
  pointer-events: none; z-index: 9999;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

/* ---------- Typography ---------- */
h1, h2, h3, h4 { font-family: 'Noto Serif SC', 'Songti SC', Georgia, serif; }

/* ---------- Nav ---------- */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 3000;
  background: rgba(245, 240, 235, 0.88);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(200, 194, 182, 0.3);
}
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 40px; height: 64px;
}
.nav-logo {
  font-family: 'Noto Serif SC', 'Songti SC', Georgia, serif;
  font-weight: 400; font-size: 16px; color: #3D3D3A; letter-spacing: 0.04em;
  cursor: pointer; user-select: none;
}
.nav-logo span { color: #6B8F71; }
.nav-toggle {
  display: none; background: none; border: none; cursor: pointer; padding: 8px;
}
.nav-toggle span {
  display: block; width: 20px; height: 1.5px; background: #3D3D3A; margin: 5px 0; border-radius: 1px;
}
.nav-links { display: flex; gap: 6px; align-items: center; }
.nav-links a {
  font-size: 13px; font-weight: 400; color: #8A8A84;
  padding: 8px 16px; border-radius: 100px; transition: all 0.3s;
}
.nav-links a:hover { color: #3D3D3A; background: rgba(200, 194, 182, 0.15); }
.nav-links a.active { color: #6B8F71; background: rgba(107, 143, 113, 0.1); }

/* ---------- Section ---------- */
.section {
  max-width: 1200px; margin: 0 auto; padding: 80px 40px;
}
.section-header { margin-bottom: 40px; }
.section-su {
  font-size: 11px; letter-spacing: 0.12em; color: #6B8F71;
  font-weight: 500; text-transform: uppercase; margin-bottom: 8px;
}
.section-title {
  font-family: 'Noto Serif SC', 'Songti SC', Georgia, serif;
  font-weight: 300; font-size: 32px; letter-spacing: 0.02em;
  color: #3D3D3A; margin-bottom: 12px;
}
.section-desc {
  font-size: 15px; color: #8A8A84; font-weight: 300;
  max-width: 480px; line-height: 1.8;
}
.section-hl { width: 40px; height: 1px; background: #C8C2B6; margin: 24px 0; }
.section.alt { background: rgba(239, 233, 226, 0.4); padding: 80px 0; }
.section.alt .in { max-width: 1200px; margin: 0 auto; padding: 0 40px; }

/* ---------- Hero ---------- */
.hero {
  min-height: 100vh; display: flex; align-items: center;
  padding: 120px 40px 80px; max-width: 1200px; margin: 0 auto;
}
.hero-grid {
  display: grid; grid-template-columns: 1fr 1.2fr; gap: 48px; align-items: center;
  width: 100%;
}
.hero .hl2 {
  font-size: 11px; letter-spacing: 0.16em; text-transform: uppercase;
  color: #6B8F71; font-weight: 500; margin-bottom: 28px;
}
.hero h1 {
  font-weight: 300; font-size: clamp(36px, 5vw, 60px);
  line-height: 1.2; letter-spacing: 0.01em; color: #2D3436;
}
.hero h1 .h { font-weight: 600; color: #2D3436; }
.hero h1 .ag { color: #6B8F71; font-weight: 400; }
.hero .tl {
  font-weight: 300; font-size: 17px; line-height: 1.9;
  color: #8A8A84; max-width: 480px; margin-top: 32px;
}
.hero-stats { display: flex; gap: 40px; margin-top: 40px; }
.hero-stats .n { font-family: 'Noto Serif SC', serif; font-weight: 600; font-size: 28px; color: #2D3436; line-height: 1; }
.hero-stats .l { font-size: 11px; color: #B8B2A6; margin-top: 6px; letter-spacing: 0.04em; }
.hero-actions { display: flex; gap: 20px; align-items: center; margin-top: 48px; flex-wrap: wrap; }
.hero-avatar-col {
  display: flex; flex-direction: column; align-items: center; gap: 28px;
}
.hero-avatar { position: relative; }
.hero-avatar img {
  width: 220px; height: 220px; border-radius: 50%;
  object-fit: cover; border: 2px solid rgba(200, 194, 182, 0.3);
  box-shadow: 0 8px 32px rgba(0,0,0,0.04);
}
.hero-avatar .r1 {
  position: absolute; top: -14px; left: -14px;
  width: 248px; height: 248px; border-radius: 50%;
  border: 1px solid rgba(107, 143, 113, 0.2); pointer-events: none;
}
.hero-avatar .r2 {
  position: absolute; top: -28px; left: -28px;
  width: 276px; height: 276px; border-radius: 50%;
  border: 1px solid rgba(107, 143, 113, 0.08); pointer-events: none;
}
.hero-name {
  text-align: center;
  font-family: 'Noto Serif SC', serif; font-weight: 600; font-size: 20px; color: #3D3D3A;
}
.hero-role { font-size: 13px; color: #B8B2A6; font-weight: 300; margin-top: 4px; letter-spacing: 0.04em; }
.hero-status {
  background: rgba(255,255,255,0.5); border: 1px solid rgba(200,194,182,0.2);
  border-radius: 12px; padding: 16px 24px; text-align: center;
  font-size: 12px; color: #8A8A84; font-weight: 300; line-height: 1.7;
}

/* ---------- Buttons ---------- */
.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 32px; background: #3D3D3A; color: #F5F0EB;
  font-size: 13px; font-weight: 400; letter-spacing: 0.04em;
  border: none; border-radius: 100px; cursor: pointer;
  font-family: inherit; transition: all 0.3s;
}
.btn-primary:hover { background: #2D2D2A; transform: translateY(-1px); }
.btn-secondary {
  font-size: 13px; color: #8A8A84; border: none; background: none;
  border-bottom: 1px solid #C8C2B6; padding-bottom: 4px;
  cursor: pointer; font-family: inherit; transition: all 0.3s;
}
.btn-secondary:hover { color: #3D3D3A; border-color: #3D3D3A; }
.btn-sm {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 20px; font-size: 12px; font-weight: 500;
  background: rgba(107, 143, 113, 0.08); color: #6B8F71;
  border: none; border-radius: 100px; cursor: pointer;
  font-family: inherit; transition: all 0.3s;
}
.btn-sm:hover { background: rgba(107, 143, 113, 0.18); }

/* ---------- Card Base ---------- */
.card {
  background: rgba(255, 255, 255, 0.6);
  border: 1px solid rgba(200, 194, 182, 0.25);
  border-radius: 16px;
  padding: 28px;
  backdrop-filter: blur(4px);
  transition: all 0.3s ease;
  cursor: pointer;
}
.card:hover {
  background: rgba(255, 255, 255, 0.85);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.04);
}
.card .card-tag {
  display: inline-block;
  font-size: 10px; letter-spacing: 0.08em; color: #6B8F71;
  font-weight: 500; text-transform: uppercase; margin-bottom: 14px;
}
.card .card-emoji { font-size: 28px; display: block; margin-bottom: 12px; }
.card h3 { font-weight: 600; font-size: 17px; color: #3D3D3A; margin-bottom: 10px; line-height: 1.4; }
.card .card-desc { font-size: 13px; color: #8A8A84; font-weight: 300; line-height: 1.8; }
.card .card-meta {
  display: flex; align-items: center; gap: 12px; margin-top: 16px;
  font-size: 11px; color: #C8C2B6;
}
.card .card-expand {
  font-size: 12px; color: #6B8F71; font-weight: 400;
  margin-top: 14px; display: flex; align-items: center; gap: 4px;
  transition: gap 0.2s;
}
.card:hover .card-expand { gap: 8px; }

/* ---------- Card Expanded Detail ---------- */
.card-detail {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.4s ease, opacity 0.3s ease, margin 0.3s ease;
  opacity: 0;
}
.card-detail.open {
  max-height: 4000px;
  opacity: 1;
}
.card-detail-inner {
  padding-top: 20px;
  margin-top: 16px;
  border-top: 1px solid rgba(200, 194, 182, 0.2);
  font-size: 14px; color: #5C5C56; font-weight: 300; line-height: 2;
}
.card-detail-inner p { margin-bottom: 14px; }
.card-detail-inner h4 {
  font-weight: 600; font-size: 15px; color: #3D3D3A;
  margin: 20px 0 10px;
}
.card-detail-inner ol, .card-detail-inner ul {
  padding-left: 20px; margin-bottom: 14px;
}
.card-detail-inner li { margin-bottom: 8px; list-style: disc; color: #5C5C56; }
.card-detail-inner .prompt-box {
  background: rgba(245, 240, 235, 0.6);
  border: 1px solid rgba(200, 194, 182, 0.3);
  border-radius: 12px; padding: 18px; margin: 14px 0;
  font-size: 13px; line-height: 1.8; color: #5C5C56;
  position: relative;
}
.card-detail-inner .prompt-box .copy-btn {
  position: absolute; top: 10px; right: 10px;
  font-size: 11px; padding: 4px 12px;
  background: rgba(107, 143, 113, 0.08); color: #6B8F71;
  border: none; border-radius: 100px; cursor: pointer;
  font-family: inherit; transition: all 0.2s;
}
.card-detail-inner .prompt-box .copy-btn:hover { background: rgba(107, 143, 113, 0.2); }
.card-detail-inner .prompt-box .copy-btn.copied { background: #6B8F71; color: #fff; }

/* ---------- Values Grid (About) ---------- */
.values-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.value-card { text-align: center; }
.value-card .vi { font-size: 22px; margin-bottom: 10px; display: block; }
.value-card h3 { font-size: 15px; font-weight: 600; margin-bottom: 6px; }
.value-card p { font-size: 13px; color: #8A8A84; font-weight: 300; line-height: 1.7; }

/* ---------- Grid Layouts ---------- */
.grid-3 { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 24px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }

/* ---------- Tag Filter Bar ---------- */
.tag-bar {
  display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 28px;
}
.tag-bar .tag {
  font-size: 12px; color: #8A8A84; font-weight: 400;
  padding: 6px 16px; border-radius: 100px;
  border: 1px solid rgba(200, 194, 182, 0.3);
  cursor: pointer; transition: all 0.3s; background: transparent;
}
.tag-bar .tag:hover { border-color: #8A8A84; color: #3D3D3A; }
.tag-bar .tag.active {
  background: rgba(107, 143, 113, 0.1);
  border-color: #6B8F71; color: #6B8F71;
}

/* ---------- Project Card (Cases) ---------- */
.project-list { display: flex; flex-direction: column; gap: 20px; }
.project-card {
  display: grid; grid-template-columns: auto 1fr; gap: 24px; align-items: start;
}
.project-card .pc-icon {
  width: 60px; height: 60px;
  background: rgba(107, 143, 113, 0.06); border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 28px; flex-shrink: 0; border: 1px solid rgba(200,194,182,0.2);
}
.project-card .pc-body h3 { margin-bottom: 6px; }
.project-card .pc-body .pc-story {
  font-size: 14px; color: #5C5C56; font-weight: 300; line-height: 1.8; margin-bottom: 10px;
}
.project-card .pc-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.project-card .pc-tags span {
  font-size: 10px; color: #6B8F71; font-weight: 400;
  padding: 3px 10px; border-radius: 100px;
  background: rgba(107, 143, 113, 0.06);
}

/* ---------- Dialogue Card ---------- */
.dialogue-card .dc-context {
  font-size: 13px; color: #5C5C56; font-weight: 300; line-height: 1.8;
  margin-bottom: 12px;
}
.dialogue-card .dc-context .who { font-weight: 500; color: #3D3D3A; }
.dialogue-card .dc-insight {
  font-size: 12px; color: #6B8F71; font-style: italic; line-height: 1.7;
  padding: 12px 16px; background: rgba(107,143,113,0.04);
  border-radius: 10px; margin-top: 12px;
}

/* ---------- Letter / 投信问茶 ---------- */
.letter-box {
  background: rgba(255,255,255,0.5);
  border: 1px solid rgba(200,194,182,0.25);
  border-radius: 16px; padding: 32px;
}
.letter-box textarea {
  width: 100%; padding: 16px; min-height: 120px;
  background: rgba(245,240,235,0.5);
  border: 1px solid rgba(200,194,182,0.3);
  border-radius: 12px; font-family: inherit; font-size: 14px;
  color: #3D3D3A; outline: none; resize: vertical;
  font-weight: 300; line-height: 1.8;
}
.letter-box textarea:focus { border-color: #6B8F71; }
.letter-box .letter-actions {
  display: flex; gap: 12px; align-items: center; margin-top: 16px;
}
.letter-status {
  font-size: 12px; color: #6B8F71; font-weight: 400;
  display: flex; align-items: center; gap: 6px;
}
.letter-inbox { margin-top: 20px; }
.letter-inbox .li-empty {
  text-align: center; padding: 40px 0;
  font-size: 13px; color: #C8C2B6; font-weight: 300;
}

/* ---------- Consulting ---------- */
.consulting-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 60px; align-items: start; }
.consulting-info h3 { font-weight: 600; font-size: 20px; color: #3D3D3A; margin-bottom: 16px; }
.consulting-info p { font-size: 14px; color: #8A8A84; font-weight: 300; line-height: 1.9; margin-bottom: 24px; }
.consulting-features { display: flex; flex-direction: column; gap: 14px; }
.consulting-features li {
  display: flex; gap: 14px; align-items: flex-start;
  font-size: 14px; color: #5C5C56; font-weight: 300; line-height: 1.6;
}
.consulting-features li .ck {
  width: 20px; height: 20px; border-radius: 50%;
  background: rgba(107,143,113,0.08);
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0; margin-top: 2px; font-size: 10px; color: #6B8F71;
}
.consulting-features li strong { font-weight: 500; color: #3D3D3A; }
.consulting-card {
  background: rgba(255,255,255,0.6);
  border: 1px solid rgba(200,194,182,0.25);
  border-radius: 16px; padding: 36px; text-align: center;
}
.consulting-card .pl {
  font-size: 11px; letter-spacing: 0.12em; color: #B8B2A6;
  text-transform: uppercase; font-weight: 500;
}
.consulting-card .pp {
  font-family: 'Noto Serif SC', serif; font-weight: 300;
  font-size: 36px; color: #3D3D3A; margin: 12px 0;
}
.consulting-card .pd { font-size: 13px; color: #8A8A84; font-weight: 300; margin-bottom: 28px; }

/* ---------- Contact Form ---------- */
.contact-form { text-align: left; }
.contact-form .field { margin-bottom: 16px; }
.contact-form .field label {
  display: block; font-size: 12px; color: #8A8A84; margin-bottom: 6px; font-weight: 400;
}
.contact-form .field input, .contact-form .field textarea {
  width: 100%; padding: 12px 16px;
  background: rgba(255,255,255,0.7);
  border: 1px solid rgba(200,194,182,0.3);
  border-radius: 8px; font-family: inherit; font-size: 13px;
  color: #3D3D3A; outline: none; transition: all 0.3s; font-weight: 300;
}
.contact-form .field input:focus, .contact-form .field textarea:focus {
  border-color: #6B8F71; background: rgba(255,255,255,0.9);
}
.contact-form .field textarea { height: 90px; resize: vertical; }
.contact-form .submit-btn {
  width: 100%; padding: 12px; background: #3D3D3A; color: #F5F0EB;
  border: none; border-radius: 8px; font-size: 13px; font-weight: 400;
  letter-spacing: 0.04em; cursor: pointer; transition: all 0.3s; font-family: inherit;
}
.contact-form .submit-btn:hover { background: #2D2D2A; }
.contact-form .submit-btn:disabled { opacity: 0.5; cursor: not-allowed; }
.success-state { padding: 30px 0; text-align: center; }
.success-state .big { font-size: 40px; display: block; margin-bottom: 12px; }
.success-state h3 { font-size: 18px; color: #3D3D3A; margin-bottom: 8px; font-weight: 500; }
.success-state p { font-size: 13px; color: #8A8A84; font-weight: 300; }

/* ---------- Contact Channels ---------- */
.contact-channels { display: flex; flex-wrap: wrap; gap: 16px; margin-top: 40px; }
.channel {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 20px; border-radius: 12px;
  flex: 1; min-width: 180px; transition: all 0.3s;
  background: rgba(255,255,255,0.4); border: 1px solid rgba(200,194,182,0.2);
}
.channel:hover { background: rgba(255,255,255,0.7); }
.channel .ci {
  width: 40px; height: 40px; border-radius: 50%;
  background: rgba(107,143,113,0.06);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; color: #6B8F71; flex-shrink: 0;
}
.channel .cn { font-size: 14px; color: #3D3D3A; font-weight: 400; }
.channel .cde { font-size: 12px; color: #B8B2A6; font-weight: 300; }

/* ---------- Footer ---------- */
footer {
  padding: 40px; max-width: 1200px; margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
  border-top: 1px solid rgba(200, 194, 182, 0.3);
}
footer .copy { font-family: 'Noto Serif SC', serif; font-size: 13px; color: #B8B2A6; font-weight: 300; }
footer .links { display: flex; gap: 24px; }
footer .links a { font-size: 12px; color: #C8C2B6; cursor: pointer; transition: color 0.3s; }
footer .links a:hover { color: #8A8A84; }

/* ---------- Toast ---------- */
.toast {
  position: fixed; bottom: 40px; left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: #3D3D3A; color: #F5F0EB;
  padding: 14px 28px; border-radius: 12px;
  font-size: 13px; z-index: 3000; opacity: 0;
  transition: all 0.4s; pointer-events: none; white-space: nowrap;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ---------- Scroll Animation ---------- */
.fade-in-up {
  opacity: 0; transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in-up.visible { opacity: 1; transform: translateY(0); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; text-align: center; }
  .hero .tl { margin: 32px auto 0; }
  .hero-stats { justify-content: center; }
  .hero-actions { justify-content: center; flex-wrap: wrap; }
  .values-grid { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: 1fr; }
  .grid-2 { grid-template-columns: 1fr; }
  .project-card { grid-template-columns: 1fr; gap: 16px; }
  .project-card .pc-icon { width: 50px; height: 50px; font-size: 24px; }
  .consulting-grid { grid-template-columns: 1fr; }
  .section { padding: 60px 24px; }
  .section.alt .in { padding: 0 24px; }
  .hero { padding: 100px 24px 60px; }
  .nav-links { display: none; }
  .nav-toggle { display: block !important; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: absolute; top: 64px; left: 0; right: 0;
    background: rgba(245,240,235,0.98); backdrop-filter: blur(12px);
    padding: 24px 40px; border-bottom: 1px solid rgba(200,194,182,0.3);
    gap: 12px; align-items: stretch;
  }
  .contact-channels { flex-direction: column; }
  .channel { min-width: auto; }
  footer { flex-direction: column; gap: 16px; text-align: center; }
}