:root {
  --bg: #0d0d0d;
  --white: #c8c2b8;
  --white-hi: #ede8e0;
  --gray-60: rgba(180,175,165,0.60);
  --gray-35: rgba(200,195,185,0.35);
  --gray-12: rgba(180,175,165,0.12);
  --mono: 'Share Tech Mono', monospace;
}
@import url('https://fonts.googleapis.com/css2?family=Share+Tech+Mono&display=swap');
*, *::before, *::after { margin:0; padding:0; box-sizing:border-box; }
html, body {
  width:100%; height:100%;
  background: var(--bg);
  color: var(--white);
  font-family: var(--mono);
  overflow-x: hidden;
}
body.light-mode { filter: invert(1); }
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: repeating-linear-gradient(
    90deg,
    rgba(255,255,255,0.03) 0px,
    rgba(255,255,255,0.03) 1px,
    transparent 1px,
    transparent 28px
  );
  z-index: 0;
  pointer-events: none;
}
#svc-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 40px;
  z-index: 100;
  border-bottom: 1px solid var(--gray-12);
  background: rgba(13,13,13,0.80);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}
#global-lang-selector {
  position: relative;
  z-index: 101;
  font-family: var(--mono);
}
.lang-dropdown-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: rgba(10, 10, 15, 0.65);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(200, 195, 185, 0.15);
  color: rgba(200, 195, 185, 0.75);
  padding: 6px 12px;
  border-radius: 2px;
  cursor: pointer;
  font-size: 0.75rem;
  letter-spacing: 1.5px;
  transition: all 0.2s ease;
  user-select: none;
}
.lang-dropdown-btn:hover,
#global-lang-selector.open .lang-dropdown-btn {
  color: var(--white-hi);
  border-color: rgba(200, 195, 185, 0.45);
  background: rgba(20, 20, 30, 0.85);
}
.lang-dropdown-menu {
  display: none;
  position: absolute;
  top: calc(100% + 6px);
  right: 0;
  min-width: 130px;
  background: rgba(12, 12, 18, 0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(200, 195, 185, 0.2);
  border-radius: 4px;
  padding: 4px 0;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.8);
  z-index: 10001;
  overflow: hidden;
}
#global-lang-selector.open .lang-dropdown-menu {
  display: block;
}
.lang-option {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  color: rgba(200, 195, 185, 0.65);
  font-size: 0.75rem;
  letter-spacing: 1px;
  cursor: pointer;
  transition: all 0.15s ease;
}
.lang-option:hover {
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
}
.lang-option.active {
  color: #fff;
  font-weight: bold;
  background: rgba(255, 255, 255, 0.12);
}
.lang-option.active::after {
  content: '✓';
  font-size: 0.7rem;
  color: #fff;
}
#svc-back {
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: 3px;
  color: var(--gray-60);
  text-decoration: none;
  border: 1px solid var(--gray-12);
  padding: 7px 16px;
  border-radius: 2px;
  transition: color .2s, border-color .2s;
}
#svc-back:hover { color: var(--white-hi); border-color: var(--gray-35); }
#site-logo {
  width: 120px;
  height: 36px;
  display: block;
}
#svc-chat {
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: 3px;
  color: var(--gray-60);
  text-decoration: none;
  border: 1px solid var(--gray-12);
  padding: 7px 16px;
  border-radius: 2px;
  transition: color .2s, border-color .2s;
}
#svc-chat:hover { color: var(--white-hi); border-color: var(--gray-35); }
#svc-body {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 62fr 38fr;
  min-height: 100vh;
  padding-top: 60px;
}
#svc-left {
  padding: 72px 60px 60px 60px;
  border-right: none;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  z-index: 2;
}
.svc-category {
  display: block;
  font-size: .62rem;
  letter-spacing: 4px;
  color: var(--gray-60);
  text-transform: uppercase;
  margin-bottom: 20px;
}
h1#svc-title {
  font-family: var(--mono);
  font-size: clamp(2.2rem, 4.5vw, 3.6rem);
  font-weight: normal;
  letter-spacing: 4px;
  color: var(--white-hi);
  line-height: 1.15;
  margin-bottom: 20px;
  text-transform: uppercase;
}
#svc-tagline {
  font-size: .95rem;
  line-height: 1.8;
  color: var(--gray-60);
  margin-bottom: 36px;
  max-width: 560px;
}
.hero-line {
  width: 48px;
  height: 1px;
  background: var(--gray-35);
  margin-bottom: 48px;
}
.svc-section {
  padding: 32px 0;
  border-top: 1px solid var(--gray-12);
  max-width: 640px;
}
.svc-section:last-child {
  border-bottom: 1px solid var(--gray-12);
}
.svc-label {
  display: block;
  font-size: .60rem;
  letter-spacing: 3.5px;
  color: var(--gray-60);
  text-transform: uppercase;
  margin-bottom: 12px;
}
.svc-section p {
  font-size: .92rem;
  line-height: 1.9;
  color: var(--white);
}
#svc-right {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
}
#svc-formula {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px 30px;
  border-left: 1px solid var(--gray-12);
  min-height: 320px;
}
#svc-formula img {
  display: none; 
}
.formula-label {
  font-size: .60rem;
  letter-spacing: 3.5px;
  color: var(--gray-60);
  text-transform: uppercase;
  margin-bottom: 28px;
}
#katex-render {
  margin: 20px 0;
  color: var(--white-hi);
  font-size: 1.4em;
  min-height: 60px;
}
#formula-math-desc {
  font-size: .78rem;
  line-height: 1.7;
  color: var(--gray-60);
  font-style: italic;
  max-width: 380px;
  margin-top: 24px;
}
#svc-cta {
  padding-top: 48px;
  border: none;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}
.cta-btn {
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--white-hi);
  background: transparent;
  border: 1px solid var(--white-hi);
  padding: 11px 28px;
  border-radius: 2px;
  cursor: pointer;
  transition: opacity .2s;
  display: inline-block;
  white-space: nowrap;
  margin-bottom: 12px;
}
.cta-btn:hover { opacity: .65; }
.cta-sub {
  font-size: .68rem;
  letter-spacing: 1px;
  color: var(--gray-60);
  font-style: italic;
  line-height: 1.6;
  white-space: nowrap;
}
#ozana-chat {
  position: fixed;
  top: 70px; right: 20px;
  width: 480px;
  max-height: calc(100vh - 90px);
  overflow-y: auto;
  z-index: 200;
  opacity: 0;
  pointer-events: none;
  transform: translateY(-16px);
  transition: opacity .4s ease, transform .4s ease;
  background: rgba(13,13,13,0.92);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--gray-12);
  border-radius: 6px;
  padding: 28px;
  display: flex;
  flex-direction: column;
}
#ozana-chat.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}
.chat-brand {
  font-size: .72rem;
  letter-spacing: 3px;
  color: var(--gray-60);
}
.chat-close {
  width: 28px; height: 28px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1rem;
  color: var(--gray-60);
  cursor: pointer;
  border: 1px solid var(--gray-12);
  border-radius: 2px;
  background: transparent;
  transition: color .2s, border-color .2s;
}
.chat-close:hover { color: var(--white); border-color: var(--gray-35); }
.chat-text {
  font-size: .95rem;
  line-height: 1.7;
  color: var(--white-hi);
  margin-bottom: 16px;
  min-height: 1.7em;
  word-break: break-word;
  white-space: pre-wrap;
}
.tw-cursor {
  display: inline-block;
  width: 2px; height: .9em;
  background: var(--white);
  margin-left: 2px;
  animation: twBlink .55s infinite;
  vertical-align: middle;
}
@keyframes twBlink { 0%,100%{opacity:1} 50%{opacity:0} }
.chat-input-wrap {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
  align-items: flex-end;
}
#chatInput {
  flex: 1;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--gray-12);
  color: var(--white-hi);
  font-family: var(--mono);
  font-size: .88rem;
  padding: 10px 12px;
  border-radius: 2px;
  outline: none;
  resize: none;
  overflow: hidden;
  min-height: 40px;
  line-height: 1.5;
  word-break: break-word;
  transition: border-color .2s;
}
#chatInput:focus { border-color: var(--gray-35); }
#chatInput::placeholder { color: var(--gray-60); opacity: .5; }
#chatSend {
  background: transparent;
  border: 1px solid var(--gray-35);
  color: var(--white);
  font-size: .85rem;
  padding: 9px 14px;
  border-radius: 2px;
  cursor: pointer;
  transition: background .2s;
}
#chatSend:hover { background: rgba(200,195,185,0.06); }
.chat-bubbles {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  opacity: 0;
  transition: opacity .5s;
}
.chat-bubbles.visible { opacity: 1; }
.chat-bubble {
  font-family: var(--mono);
  font-size: .70rem;
  letter-spacing: 1.5px;
  color: var(--gray-60);
  border: 1px solid var(--gray-12);
  padding: 5px 12px;
  border-radius: 20px;
  cursor: pointer;
  background: transparent;
  transition: color .2s, border-color .2s, background .2s;
}
.chat-bubble:hover {
  color: var(--white);
  border-color: var(--gray-35);
  background: rgba(200,195,185,0.06);
}
#chat-mini {
  position: fixed;
  bottom: 20px; right: 20px;
  z-index: 200;
  width: 44px; height: 44px;
  border-radius: 50%;
  border: 1px solid var(--gray-35);
  background: rgba(13,13,13,0.8);
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: .6rem;
  letter-spacing: 1px;
  color: var(--gray-60);
  animation: miniPulse 3s infinite ease-in-out;
}
#chat-mini.visible { display: flex; }
@keyframes miniPulse {
  0%,100% { box-shadow: 0 0 0 rgba(200,195,185,0); }
  50% { box-shadow: 0 0 20px rgba(200,195,185,0.10); }
}
#theme-toggle {
  position: fixed;
  top: 14px; right: 140px;
  z-index: 300;
  font-size: 1rem;
  color: var(--gray-60);
  background: transparent;
  border: 1px solid var(--gray-12);
  padding: 6px 11px;
  border-radius: 2px;
  cursor: pointer;
  line-height: 1;
  transition: color .2s, border-color .2s;
}
#theme-toggle:hover { color: var(--white-hi); border-color: var(--gray-35); }
#lang-selector {
  position: fixed;
  top: 14px; right: 200px;
  z-index: 300;
  display: flex;
  gap: 2px;
  align-items: center;
}
.lang-btn {
  font-family: var(--mono);
  font-size: .58rem;
  letter-spacing: 1.5px;
  color: var(--gray-60);
  background: transparent;
  border: 1px solid transparent;
  padding: 5px 8px;
  border-radius: 2px;
  cursor: pointer;
  transition: color .2s, border-color .2s;
  text-transform: uppercase;
}
.lang-btn:hover { color: var(--white-hi); border-color: var(--gray-12); }
.lang-btn.active {
  color: var(--white-hi);
  border-color: var(--gray-35);
}
@media(max-width: 899px) {
  #svc-body {
    grid-template-columns: 1fr;
  }
  #svc-left {
    border-right: none;
    border-bottom: 1px solid var(--gray-12);
    padding: 60px 24px 40px 24px;
  }
  #svc-right {
    padding: 32px 24px 60px 24px;
  }
  #svc-header { padding: 0 20px; }
  #ozana-chat {
    top: 0; left: 0; right: 0;
    width: 100%;
    max-height: 60vh;
    border-radius: 0;
    border: none;
    border-bottom: 1px solid var(--gray-12);
  }
  #theme-toggle { top: 14px; right: 100px; }
  #lang-selector { display: none; }
}
#ozana-chat {
  overflow: hidden !important;
}
#ozana-chat .chat-text {
  flex: 1 1 auto !important;
  min-height: 0 !important;
  max-height: 48vh !important;
  overflow-y: auto !important;
  margin-bottom: 12px !important;
  padding-right: 6px !important;
  word-break: break-word !important;
  white-space: pre-wrap !important;
}
#ozana-chat .chat-text::-webkit-scrollbar {
  width: 4px;
}
#ozana-chat .chat-text::-webkit-scrollbar-track {
  background: rgba(255, 255, 255, 0.04);
  border-radius: 2px;
}
#ozana-chat .chat-text::-webkit-scrollbar-thumb {
  background: rgba(200, 195, 185, 0.35);
  border-radius: 2px;
}
#ozana-chat .chat-input-wrap,
#ozana-chat .chat-bubbles {
  flex-shrink: 0 !important;
}