:root {
    --bg: #f4f4f2;
    --sand-light: #eaeae6;
    --sand-mid: #deded8;
    --stone-grey: #8c8c88;
    --stone-light: #b0b0ac;
    
    /* Magnetic Ferrofluid & Organic Inks */
    --iron-black: #141414;
    --iron-liquid: #000000;
    --iron-alpha: rgba(20, 20, 20, 0.05);
    --iron-raised: rgba(20, 20, 20, 0.08);
    --line: rgba(20, 20, 20, 0.08);
    --line-focus: rgba(20, 20, 20, 0.3);
    --ok: #1a7f5a;
    
    --text: #141414;
    --text-dim: #70706c;
    --text-light: #ffffff;
    
    --mono: "JetBrains Mono", "SF Mono", Consolas, monospace;
    --sans: "Outfit", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  }

  * { box-sizing: border-box; }
  
  html, body { 
    height: 100%; 
    background-color: var(--bg);
  }

  body {
    margin: 0;
    color: var(--text);
    font-family: var(--sans);
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow-x: hidden;
    /* Microscopic Zen Sand matrix overlay */
    background-image: radial-gradient(rgba(20, 20, 20, 0.05) 1.5px, transparent 0);
    background-size: 20px 20px;
  }

  /* --- Magnetic Ambient Micro-Blobs (Drifting Fluid Fills) --- */
  .ferro-universe {
    position: fixed;
    top: 0; left: 0; width: 100vw; height: 100vh;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
  }

  .ferro-blob {
    position: absolute;
    filter: blur(80px);
    opacity: 0.12;
    background: var(--iron-liquid);
    animation: magneticDrift 28s infinite alternate ease-in-out, organicMorph 20s infinite alternate ease-in-out;
  }

  .blob-1 {
    width: 45vw; height: 45vw;
    max-width: 450px; max-height: 450px;
    top: -10%; left: -5%;
  }

  .blob-2 {
    width: 50vw; height: 50vw;
    max-width: 500px; max-height: 500px;
    bottom: -15%; right: -5%;
    animation-delay: -8s;
  }

  @keyframes magneticDrift {
    0% { transform: translate(0, 0) scale(1) rotate(0deg); }
    50% { transform: translate(8%, 12%) scale(1.15) rotate(180deg); }
    100% { transform: translate(-8%, -6%) scale(0.9) rotate(360deg); }
  }

  @keyframes organicMorph {
    0% { border-radius: 42% 58% 70% 30% / 45% 45% 55% 55%; }
    40% { border-radius: 70% 30% 52% 48% / 30% 40% 60% 70%; }
    70% { border-radius: 50% 50% 65% 35% / 60% 40% 60% 40%; }
    100% { border-radius: 42% 58% 70% 30% / 45% 45% 55% 55%; }
  }

  /* --- Layout & Dynamic Inward Swell --- */
  .wrap {
    max-width: 620px;
    width: 100%;
    margin: 0 auto;
    padding: 40px 20px 80px;
    min-height: 100%;
    display: flex;
    flex-direction: column;
    gap: 28px;
    position: relative;
    z-index: 1;
  }

  @keyframes magneticCondense {
    0% { opacity: 0; transform: translateY(16px) scale(0.97); filter: blur(10px); }
    60% { filter: blur(0px); }
    100% { opacity: 1; transform: translateY(0) scale(1); filter: blur(0); }
  }

  /* ---------- Header ---------- */
  header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 24px;
    background: rgba(255, 255, 255, 0.4);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--line);
    border-radius: 40px 20px 40px 20px;
    box-shadow: 0 8px 30px rgba(20, 20, 20, 0.02);
    animation: magneticCondense 0.8s cubic-bezier(0.16, 1, 0.3, 1);
  }

  .brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-family: var(--sans);
    letter-spacing: -0.04em;
    text-decoration: none;
  }

  .brand .jack {
    width: 14px;
    height: 14px;
    background: var(--iron-black);
    box-shadow: 0 0 0 4px rgba(20, 20, 20, 0.06);
    animation: organicMorph 6s infinite ease-in-out;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  }

  .brand:hover .jack {
    transform: scale(1.25);
    background: var(--iron-liquid);
    box-shadow: 0 0 12px rgba(0, 0, 0, 0.15);
  }

  .brand b { 
    font-weight: 800; 
    font-size: 21px; 
    color: var(--iron-black);
  }

  .presence {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 600;
    color: var(--text-dim);
    display: flex; 
    align-items: center; 
    gap: 8px;
    background: rgba(255, 255, 255, 0.6);
    padding: 6px 16px;
    border-radius: 30px;
    border: 1px solid var(--line);
  }

  .presence .dot { 
    width: 7px; 
    height: 7px; 
    border-radius: 50%; 
    background: var(--ok); 
    box-shadow: 0 0 12px var(--ok);
  }

  /* ---------- Pairing Screen ---------- */
  .pair-card {
    background: var(--iron-alpha);
    backdrop-filter: blur(30px);
    -webkit-backdrop-filter: blur(30px);
    border: 1px solid var(--line);
    border-radius: 32px 48px 36px 60px;
    padding: 52px 36px;
    text-align: center;
    box-shadow: 0 20px 48px -15px rgba(20, 20, 20, 0.04);
    animation: magneticCondense 0.7s cubic-bezier(0.16, 1, 0.3, 1);
  }

  .pair-card h1 {
    font-size: 28px;
    margin: 0 0 12px;
    font-weight: 800;
    letter-spacing: -0.03em;
    color: var(--iron-black);
  }

  .pair-card p { 
    color: var(--text-dim); 
    font-size: 14.5px; 
    font-weight: 400;
    margin: 0 auto 36px; 
    max-width: 400px;
    line-height: 1.6; 
  }

  .code-plate {
    display: inline-block;
    font-family: var(--mono);
    font-size: 34px;
    letter-spacing: 0.22em;
    font-weight: 700;
    color: var(--iron-black);
    background: #ffffff;
    border: 1px solid var(--sand-mid);
    border-radius: 20px 28px 20px 32px;
    padding: 16px 36px;
    margin-bottom: 32px;
    box-shadow: inset 0 2px 4px rgba(20, 20, 20, 0.02);
    transition: all 0.4s cubic-bezier(0.19, 1, 0.22, 1);
  }

  .code-plate:hover {
    letter-spacing: 0.26em;
    transform: scale(1.02);
    border-color: var(--stone-grey);
  }

  #qr { 
    background: #ffffff; 
    padding: 16px; 
    border-radius: 24px;
    border: 1px solid var(--sand-mid);
    display: inline-block; 
    margin-bottom: 32px; 
    line-height: 0; 
    box-shadow: 0 14px 32px -10px rgba(20, 20, 20, 0.08);
    transition: transform 0.4s cubic-bezier(0.19, 1, 0.22, 1);
  }

  #qr:hover {
    transform: scale(1.03);
  }

  #qr img {
    display: block;
    border-radius: 12px;
  }

  .pair-actions { 
    display: flex; 
    gap: 12px; 
    justify-content: center; 
    flex-wrap: wrap; 
  }

  .join-row { 
    display: flex; 
    gap: 10px; 
    margin-top: 36px; 
    border-top: 1px solid var(--sand-mid);
    padding-top: 32px;
  }

  .join-row input {
    flex: 1; 
    min-width: 0;
    font-family: var(--mono);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    font-weight: 600;
    background: rgba(255, 255, 255, 0.8);
    border: 1px solid var(--sand-mid);
    color: var(--iron-black);
    border-radius: 40px;
    padding: 14px 20px;
    font-size: 13px;
    transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  }

  .join-row input:focus {
    outline: none;
    border-color: var(--iron-black);
    background: #ffffff;
    box-shadow: 0 0 0 3px rgba(20, 20, 20, 0.05);
  }

  .join-row input::placeholder {
    color: var(--stone-light);
  }

  /* ---------- Fluid Ferrofluid Pill Buttons ---------- */
  button {
    font-family: var(--sans);
    font-size: 13.5px;
    font-weight: 700;
    letter-spacing: 0.02em;
    border-radius: 20px 30px 20px 30px;
    border: 1px solid var(--sand-mid);
    background: #ffffff;
    color: var(--iron-black);
    padding: 13px 26px;
    cursor: pointer;
    transition: all 0.5s cubic-bezier(0.34, 1.75, 0.64, 1); /* Liquid spring kinetic bounce */
    display: inline-flex;
    align-items: center;
    justify-content: center;
    user-select: none;
    box-shadow: 0 4px 12px rgba(20, 20, 20, 0.03);
  }

  button:hover {
    background: var(--sand-light);
    border-color: var(--stone-grey);
    transform: translateY(-3px) scale(1.02);
    border-radius: 30px 20px 30px 20px;
    box-shadow: 0 8px 20px rgba(20, 20, 20, 0.06);
  }

  button:active { 
    transform: translateY(0) scale(0.96); 
  }

  button.primary {
    background: var(--iron-black);
    border-color: var(--iron-black);
    color: #ffffff;
    box-shadow: 0 8px 24px rgba(20, 20, 20, 0.12);
  }

  button.primary:hover {
    background: var(--iron-liquid);
    border-radius: 14px 36px 20px 28px / 28px 16px 32px 18px; /* Organic Ferrofluid Cohesion */
    transform: scale(1.04) translateY(-3px);
    box-shadow: 0 12px 32px rgba(20, 20, 20, 0.2);
  }

  button.primary:active {
    border-radius: 40px;
    transform: scale(0.95);
  }

  button.ghost { 
    background: transparent; 
    border-color: transparent;
    box-shadow: none;
  }
  
  button.ghost:hover {
    background: rgba(255, 255, 255, 0.6);
    border-color: var(--sand-mid);
    border-radius: 14px 36px 20px 28px / 32px 28px 32px 28px;
    transform: scale(1.04) translateY(-3px);
    box-shadow: rgba(255, 255, 255, 0.6);
  }

  button.small { 
    padding: 8px 18px; 
    font-size: 12px; 
    border-radius: 20px 30px;
  }

  /* ---------- Composer ---------- */
  .composer {
    background: var(--iron-alpha);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--line);
    border-radius: 32px 20px 40px 20px;
    padding: 20px;
    margin-bottom: 28px;
    box-shadow: 0 14px 32px -12px rgba(20, 20, 20, 0.04);
    animation: magneticCondense 0.6s cubic-bezier(0.16, 1, 0.3, 1);
  }

  textarea {
    width: 100%;
    resize: vertical;
    min-height: 102px;
    background: rgba(255, 255, 255, 0.7);
    border: 1px solid var(--sand-mid);
    border-radius: 18px;
    color: var(--iron-black);
    font-family: var(--sans);
    font-size: 14.5px;
    font-weight: 400;
    padding: 16px;
    line-height: 1.6;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  }

  textarea:focus { 
    outline: none; 
    border-color: var(--iron-black);
    background: #ffffff;
    box-shadow: 0 0 0 3px rgba(20, 20, 20, 0.05);
  }

  textarea::placeholder {
    color: var(--stone-light);
  }

  .composer-foot {
    display: flex; 
    align-items: center; 
    justify-content: space-between;
    margin-top: 14px;
  }

  .composer-foot .hint { 
    font-size: 11.5px; 
    color: var(--text-dim); 
    font-family: var(--mono);
  }

  .file-btn { 
    display: flex; 
    align-items: center; 
    gap: 8px; 
  }

  /* ---------- History List ---------- */
  .section-label {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 700;
    color: var(--stone-grey);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin: 8px 6px 16px;
    display: flex; 
    justify-content: space-between; 
    align-items: center;
  }

  .item {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--line);
    border-left: 4px solid var(--iron-black);
    border-radius: 24px 36px 24px 36px;
    padding: 20px;
    margin-bottom: 16px;
    box-shadow: 0 6px 20px -6px rgba(20, 20, 20, 0.03);
    animation: liquidGrowth 0.5s cubic-bezier(0.34, 1.75, 0.64, 1);
    transition: all 0.4s cubic-bezier(0.19, 1, 0.22, 1);
  }

  .item:hover {
    border-color: var(--stone-grey);
    transform: translateY(-3px) scale(1.008);
    border-radius: 36px 24px 36px 24px;
    box-shadow: 0 12px 28px -8px rgba(20, 20, 20, 0.06);
  }

  @keyframes liquidGrowth { 
    from { opacity: 0; transform: translateY(20px) scale(0.95); filter: blur(4px); } 
    to { opacity: 1; transform: none; filter: blur(0); } 
  }

  .item-meta {
    display: flex; 
    justify-content: space-between; 
    align-items: center;
    font-family: var(--mono); 
    font-size: 11px; 
    font-weight: 600;
    color: var(--text-dim);
    margin-bottom: 12px;
    border-bottom: 1px solid var(--sand-light);
    padding-bottom: 10px;
  }

  .item-text {
    font-size: 14.5px;
    font-weight: 400;
    line-height: 1.65;
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 240px;
    overflow: auto;
    margin-bottom: 16px;
    color: var(--iron-black);
  }

  .item img { 
    max-width: 100%; 
    border-radius: 14px; 
    margin-bottom: 16px; 
    display: block; 
    border: 1px solid var(--sand-mid);
  }

  .item-actions { 
    display: flex; 
    gap: 8px; 
  }

  .empty {
    text-align: center;
    color: var(--text-dim);
    font-size: 14px;
    font-weight: 400;
    padding: 64px 28px;
    border: 1px dashed var(--stone-light);
    border-radius: 24px;
    line-height: 1.6;
    background: var(--iron-alpha);
    animation: magneticCondense 0.6s cubic-bezier(0.16, 1, 0.3, 1);
  }

  .copied-flash { 
    background-color: var(--iron-black) !important; 
    color: #ffffff !important;
    border-color: var(--iron-black) !important;
    transform: scale(1.04) !important;
    border-radius: 14px 30px 16px 24px !important;
  }

  .footer-note {
    text-align: center; 
    color: var(--text-dim); 
    font-size: 12px; 
    font-weight: 400;
    margin-top: auto; 
    padding-top: 36px;
    line-height: 1.6;
    border-top: 1px solid var(--sand-mid);
  }

  .footer-note a { 
    color: var(--iron-black); 
    text-decoration: none; 
    font-weight: 700;
    border-bottom: 1px solid transparent;
    transition: all 0.2s ease;
  }
  
  .footer-note a:hover {
    border-bottom-color: var(--iron-black);
  }

  /* Micro Scrollbars */
  ::-webkit-scrollbar {
    width: 5px;
    height: 5px;
  }
  ::-webkit-scrollbar-track {
    background: transparent;
  }
  ::-webkit-scrollbar-thumb {
    background: var(--sand-mid);
    border-radius: 10px;
  }
  ::-webkit-scrollbar-thumb:hover {
    background: var(--stone-grey);
  }

  @media (max-width: 480px) {
    .wrap { padding: 20px 14px 60px; }
    .pair-card { padding: 36px 20px; border-radius: 24px; }
    .code-plate { font-size: 26px; letter-spacing: 0.16em; padding: 14px 20px; }
    .join-row { flex-direction: column; }
    .join-row button { width: 100%; }
  }

  /* ---------- Icon buttons (theme toggle, notification bell) ---------- */
  .icon-btn {
    padding: 8px 10px;
    font-size: 15px;
    line-height: 1;
    border-radius: 50%;
  }
  .icon-btn:hover {
    border-radius: 50%;
  }

  /* ---------- Dark theme ----------
     Same organic/ferrofluid shapes and motion, inverted palette: the
     "iron" ink becomes light-on-dark instead of dark-on-light. */
  :root[data-theme="dark"] {
    --bg: #121212;
    --sand-light: #1c1c1a;
    --sand-mid: #2a2a27;
    --stone-grey: #96968f;
    --stone-light: #5c5c57;

    --iron-black: #f2f2ee;
    --iron-liquid: #ffffff;
    --iron-alpha: rgba(242, 242, 238, 0.05);
    --iron-raised: rgba(242, 242, 238, 0.09);
    --line: rgba(242, 242, 238, 0.1);
    --line-focus: rgba(242, 242, 238, 0.32);
    --ok: #4ade80;

    --text: #f2f2ee;
    --text-dim: #9c9c96;
    --text-light: #141414;
  }

  :root[data-theme="dark"] body {
    background-image: radial-gradient(rgba(242, 242, 238, 0.05) 1.5px, transparent 0);
  }

  :root[data-theme="dark"] .ferro-blob {
    background: var(--iron-liquid);
    opacity: 0.05;
  }

  :root[data-theme="dark"] header {
    background: rgba(20, 20, 20, 0.5);
  }

  :root[data-theme="dark"] .presence {
    background: rgba(255, 255, 255, 0.05);
  }

  :root[data-theme="dark"] .code-plate,
  :root[data-theme="dark"] #qr,
  :root[data-theme="dark"] button {
    background: #1a1a1a;
  }

  :root[data-theme="dark"] textarea,
  :root[data-theme="dark"] .join-row input {
    background: rgba(255, 255, 255, 0.04);
  }

  :root[data-theme="dark"] textarea:focus,
  :root[data-theme="dark"] .join-row input:focus {
    background: rgba(255, 255, 255, 0.07);
  }

  :root[data-theme="dark"] button.primary {
    background: var(--iron-black);
    color: #141414;
  }

  :root[data-theme="dark"] button.primary:hover {
    background: var(--iron-liquid);
  }

  :root[data-theme="dark"] .copied-flash {
    background-color: var(--iron-black) !important;
    color: #141414 !important;
  }

  :root[data-theme="dark"] .item {
    background: rgba(255, 255, 255, 0.03);
  }

  :root[data-theme="dark"] #roomLabel {
    background: rgba(255, 255, 255, 0.06) !important;
  }