:root {
    --bg: #0a0a0a;
    --card: #111111;
    --accent: #ffffff;
    --accent-hover: #f0f0f0;
    --text: #ffffff;
    --muted: #a0a0a0;
    --border: rgba(255, 255, 255, 0.1);
    --border-hover: rgba(255, 255, 255, 0.2);
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter", system-ui, sans-serif;
  }
  
  body {
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }
  
  /* navbar */
  
  .navbar {
    position: sticky;
    top: 0;
    width: 100%;
    padding: 0.75rem 5vw;
    background: rgba(10, 10, 10, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    min-height: 75px;
    box-sizing: border-box;
  }
  
  .navbar-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  
  .navbar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
  }
  
  .navbar-logo {
    width: 45px;
    height: 45px;
    object-fit: contain;
    flex-shrink: 0;
    display: block;
  }

  .navbar-text {
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--text);
    letter-spacing: -0.01em;
    line-height: 45px;
  }
  
  /* hero */
  
  .hero {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 4rem;
    padding: 8rem 5vw 10rem;
    background: linear-gradient(to bottom, 
      rgba(10, 10, 10, 0.5) 0%,
      rgba(10, 10, 10, 0.4) 30%,
      rgba(10, 10, 10, 0.3) 60%,
      rgba(10, 10, 10, 0.2) 80%,
      transparent 100%);
    min-height: 85vh;
    max-width: 1400px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
  }

  .hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100vw;
    height: 100%;
    background-image: url('messengerai_bg1.png');
    background-size: cover;
    background-position: center top;
    background-repeat: no-repeat;
    z-index: -2;
    pointer-events: none;
  }

  .hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100vw;
    height: 400px;
    background: linear-gradient(to bottom, 
      rgba(10, 10, 10, 0) 0%,
      rgba(10, 10, 10, 0.3) 40%,
      rgba(10, 10, 10, 0.6) 70%,
      rgba(10, 10, 10, 0.9) 90%,
      var(--bg) 100%);
    pointer-events: none;
    z-index: -1;
  }

  .hero-content,
  .hero-visual {
    position: relative;
    z-index: 1;
  }
  
  .hero-content {
    max-width: 600px;
    flex: 1;
  }
  
  .hero h1 {
    font-size: clamp(3.5rem, 8vw, 6rem);
    font-weight: 600;
    letter-spacing: -0.04em;
    margin-bottom: 1.5rem;
    line-height: 1.1;
  }
  
  .hero h1 em {
    font-style: italic;
    font-weight: 400;
  }
  
  .subtitle {
    color: rgba(255, 255, 255, 0.95);
    font-size: clamp(1.1rem, 2vw, 1.25rem);
    margin-bottom: 2.5rem;
    max-width: 500px;
    line-height: 1.7;
    font-weight: 400;
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(20px);
    padding: 1.5rem 2rem;
    border-radius: 12px;
    border: 1px solid var(--border);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    display: inline-block;
  }
  
  .primary-btn {
    background: var(--accent);
    color: var(--bg);
    border: none;
    padding: 1rem 2rem;
    font-weight: 500;
    font-size: 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-block;
    text-decoration: none;
  }
  
  .primary-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
  }
  
  .hero-visual {
    position: relative;
    flex: 1;
    min-height: 350px;
    max-width: 500px;
  }
  
  .bubble {
    position: absolute;
    background: rgb(33, 138, 255);
    color: white;
    padding: 1.1rem 1.4rem 1.2rem;
    border-radius: 18px;
    font-size: 1.05rem;
    max-width: 240px;
    transition: all 0.3s ease;
    font-weight: 500;
    box-shadow: 0 4px 20px rgba(33, 138, 255, 0.3),
                0 2px 8px rgba(33, 138, 255, 0.2);
    line-height: 1.4;
    word-wrap: break-word;
    overflow-wrap: break-word;
    box-sizing: border-box;
  }

  .bubble::after {
    content: '';
    position: absolute;
    width: 15px;
    height: 15px;
    background: rgb(33, 138, 255);
  }

  .bubble:hover {
    background: rgb(28, 128, 245);
    box-shadow: 0 6px 25px rgba(33, 138, 255, 0.4),
                0 3px 10px rgba(33, 138, 255, 0.3);
  }

  .bubble:hover::after {
    background: rgb(28, 128, 245);
  }

  .bubble-one {
    top: 1%;
    right: 5%;
    animation: float 6s ease-in-out infinite;
    border-bottom-right-radius: 5px;
  }

  .bubble-one::after {
    right: 8px;
    bottom: -5px;
    width: 16px;
    height: 16px;
    transform: rotate(45deg);
    border-radius: 0 0 0 14px;
  }

  .bubble-two {
    top: 35%;
    left: 2%;
    animation: float 8s ease-in-out infinite 1s;
    border-bottom-left-radius: 5px;
  }

  .bubble-two::after {
    left: 10px;
    bottom: -6px;
    width: 18px;
    height: 18px;
    transform: rotate(-45deg);
    border-radius: 14px 0 0 0;
  }

  .bubble-three {
    bottom: 6%;
    right: 25%;
    animation: float 7s ease-in-out infinite 2s;
    border-bottom-right-radius: 5px;
  }

  .bubble-three::after {
    right: 8px;
    bottom: -5px;
    width: 16px;
    height: 16px;
    transform: rotate(45deg);
    border-radius: 0 0 0 14px;
  }
  
  @keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
  }
  
  /* demo */
  
  .demo {
    padding: 8rem 5vw;
    max-width: 1400px;
    margin: 0 auto;
    position: relative;
    margin-top: -150px;
    padding-top: 14rem;
    z-index: 2;
  }
  
  .demo h2,
  .flow h2,
  .cta h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 600;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
    line-height: 1.2;
  }
  
  .section-text {
    color: var(--muted);
    font-size: clamp(1rem, 1.5vw, 1.15rem);
    margin-bottom: 3rem;
    max-width: 600px;
    line-height: 1.7;
  }
  
  .demo-layout {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
  }
  
  .chat-panel {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border);
    border-radius: 16px;
    flex: 1 1 400px;
    min-height: 500px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: all 0.3s ease;
  }

  .chat-panel.study-background .chat-header {
    background: rgba(255, 255, 255, 0.01);
    position: relative;
    z-index: 2;
  }

  .chat-panel.study-background .chat-messages {
    position: relative;
  }

  .chat-panel.study-background .chat-messages::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('ringnotebookbg2.png') center/cover no-repeat;
    opacity: 0.8;
    pointer-events: none;
    z-index: 0;
  }

  .chat-panel.travel-background .chat-header {
    background: rgba(255, 255, 255, 0.01);
    position: relative;
    z-index: 2;
  }

  .chat-panel.travel-background .chat-messages {
    position: relative;
  }

  .chat-panel.travel-background .chat-messages::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('travelbg2.png') center/cover no-repeat;
    opacity: 0.8;
    pointer-events: none;
    z-index: 0;
  }

  .chat-panel.fun-background .chat-header {
    background: rgba(255, 255, 255, 0.01);
    position: relative;
    z-index: 2;
  }

  .chat-panel.fun-background .chat-messages {
    position: relative;
  }

  .chat-panel.fun-background .chat-messages::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('rizz.jpg') center/cover no-repeat;
    opacity: 0.8;
    pointer-events: none;
    z-index: 0;
  }

  .chat-panel.sports-background .chat-header {
    background: rgba(255, 255, 255, 0.01);
    position: relative;
    z-index: 2;
  }

  .chat-panel.sports-background .chat-messages {
    position: relative;
  }

  .chat-panel.sports-background .chat-messages::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('bcourt.jpg') center/cover no-repeat;
    opacity: 0.8;
    pointer-events: none;
    z-index: 0;
  }
  
  .chat-panel:hover {
    border-color: var(--border-hover);
  }
  
  .chat-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(255, 255, 255, 0.01);
  }
  
  .chat-title {
    font-weight: 500;
    font-size: 1rem;
  }
  
  .chat-messages {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    overflow-y: auto;
    flex: 1;
  }
  
  .msg {
    max-width: 75%;
    padding: 0.75rem 1rem;
    border-radius: 12px;
    font-size: 0.9rem;
    line-height: 1.5;
    position: relative;
    z-index: 1;
  }
  
  .msg.sender {
    background: rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(255, 255, 255, 0.15);
    align-self: flex-start;
    position: relative;
    z-index: 1;
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.1) inset,
                0 0 8px rgba(255, 255, 255, 0.05),
                0 2px 8px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
  }
  
  .msg.sender::before {
    content: '';
    position: absolute;
    top: -1px;
    left: -1px;
    right: -1px;
    bottom: -1px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: -1;
    opacity: 0.6;
  }
  
  .chat-panel.study-background .msg.sender {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.12) inset,
                0 0 10px rgba(255, 255, 255, 0.08),
                0 2px 10px rgba(0, 0, 0, 0.25);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }
  
  .chat-panel.study-background .msg.sender::before {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    opacity: 0.7;
  }

  .chat-panel.travel-background .msg.sender {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.12) inset,
                0 0 10px rgba(255, 255, 255, 0.08),
                0 2px 10px rgba(0, 0, 0, 0.25);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }

  .chat-panel.travel-background .msg.sender::before {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    opacity: 0.7;
  }

  .chat-panel.fun-background .msg.sender {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.12) inset,
                0 0 10px rgba(255, 255, 255, 0.08),
                0 2px 10px rgba(0, 0, 0, 0.25);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }

  .chat-panel.fun-background .msg.sender::before {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    opacity: 0.7;
  }

  .chat-panel.sports-background .msg.sender {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.12) inset,
                0 0 10px rgba(255, 255, 255, 0.08),
                0 2px 10px rgba(0, 0, 0, 0.25);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }

  .chat-panel.sports-background .msg.sender::before {
    background: rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    opacity: 0.7;
  }
  
  .msg.user {
    background: var(--accent);
    color: var(--bg);
    align-self: flex-end;
    font-weight: 500;
  }
  
  /* agent panel */
  
  .agent-panel {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border);
    border-radius: 16px;
    flex: 1 1 400px;
    min-height: 500px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: all 0.3s ease;
  }
  
  .agent-panel:hover {
    border-color: var(--border-hover);
  }
  
  .scenario-tabs {
    display: flex;
    gap: 0.5rem;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border);
    flex-wrap: wrap;
    background: rgba(255, 255, 255, 0.01);
  }
  
  .scenario-btn {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--muted);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 400;
    transition: all 0.2s ease;
  }
  
  .scenario-btn:hover {
    border-color: var(--border-hover);
    color: var(--text);
  }
  
  .scenario-btn.active {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.3);
    color: var(--text);
  }
  
  .agent-steps {
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    overflow-y: auto;
    flex: 1;
  }
  
  .step-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1rem 1.25rem;
    transition: all 0.2s ease;
  }
  
  .step-card:hover {
    border-color: var(--border-hover);
    background: rgba(255, 255, 255, 0.05);
  }
  
  .step-label {
    font-size: 0.7rem;
    color: var(--muted);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: 500;
  }
  
  .step-title {
    font-weight: 500;
    margin-bottom: 0.5rem;
    font-size: 1rem;
  }
  
  .step-body {
    font-size: 0.9rem;
    color: var(--muted);
    line-height: 1.6;
  }
  
  /* flow */
  
  .flow {
    padding: 8rem 5vw;
    max-width: 1400px;
    margin: 0 auto;
  }
  
  .flow-steps {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
  }
  
  .flow-card {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2rem;
    flex: 1 1 280px;
    transition: all 0.3s ease;
  }
  
  .flow-card:hover {
    border-color: var(--border-hover);
    background: rgba(255, 255, 255, 0.04);
    transform: translateY(-2px);
  }
  
  .flow-card h3 {
    margin-bottom: 0.75rem;
    font-size: 1.25rem;
    font-weight: 500;
    letter-spacing: -0.01em;
  }
  
  .flow-card p {
    color: var(--muted);
    line-height: 1.7;
    font-size: 0.95rem;
  }
  
  .cta {
    text-align: center;
    padding: 8rem 5vw 10rem;
    background: var(--bg);
    max-width: 1400px;
    margin: 0 auto;
  }
  
  .cta p {
    color: var(--muted);
    font-size: clamp(1rem, 1.5vw, 1.15rem);
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.7;
  }
  
  @media (max-width: 920px) {
    .navbar {
      padding: 1rem 5vw;
      min-height: 60px;
    }
    .navbar-logo {
      width: 36px;
      height: 36px;
    }
    .navbar-text {
      font-size: 1.2rem;
      line-height: 36px;
    }
    .hero {
      flex-direction: column;
      padding: 4rem 5vw 6rem;
      text-align: center;
    }
    .hero-content {
      max-width: 100%;
    }
    .hero-visual {
      min-height: 250px;
      max-width: 100%;
    }
    .demo-layout {
      flex-direction: column;
    }
    .demo,
    .flow,
    .cta {
      padding: 4rem 5vw;
    }
  }