:root {
  --color-bg: #faf7f2;
  --color-surface: #ffffff;
  --color-primary: #16191f;
  --color-primary-light: #f4f0e6;
  --color-accent: #b56565;
  --color-border: #e8dfd1;
  --color-text: #232731;
  --color-text-muted: #626977;
  --color-danger: #bd4b4b;
  --font-sans: 'Plus Jakarta Sans', sans-serif;
  --font-serif: 'Playfair Display', serif;
  --radius: 12px;
  --transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { background-color: var(--color-bg); color: var(--color-text); font-family: var(--font-sans); min-height: 100vh; display: flex; flex-direction: column; }

.global-header { background-color: rgba(250, 247, 242, 0.9); backdrop-filter: blur(12px); border-bottom: 1px solid var(--color-border); position: sticky; top: 0; z-index: 10; }
.header-container { max-width: 1200px; margin: 0 auto; padding: 1rem 2rem; display: flex; justify-content: space-between; align-items: center; }
.brand-block { display: flex; flex-direction: column; }
.logo { font-family: var(--font-serif); font-size: 1.5rem; color: var(--color-accent); text-decoration: none; font-weight: 500; }
.tagline { font-size: 0.65rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--color-text-muted); margin-top: 0.1rem; }

#shell-root { flex: 1; max-width: 1200px; width: 100%; margin: 0 auto; padding: 2rem; display: flex; flex-direction: column; }

/* Desktop-first Grid Configuration */
.messenger-container { display: grid; grid-template-columns: 340px 1fr; gap: 2rem; flex: 1; min-height: 70vh; }

.sidebar-panel { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius); padding: 1.5rem; display: flex; flex-direction: column; gap: 1.5rem; }
.chat-workspace { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius); display: flex; flex-direction: column; overflow: hidden; }

.channel-list { flex: 1; overflow-y: auto; display: flex; flex-direction: column; gap: 0.5rem; }
.channel-card { padding: 1rem; border: 1px solid var(--color-border); border-radius: 8px; cursor: pointer; transition: var(--transition); }
.channel-card:hover, .channel-card.active { background: var(--color-primary-light); border-color: var(--color-accent); }

.chat-stream { flex: 1; padding: 2rem; overflow-y: auto; display: flex; flex-direction: column; gap: 1.5rem; background: #fffcf9; position: relative; }
.message-packet { max-width: 75%; display: flex; flex-direction: column; gap: 0.25rem; position: relative; }
.message-packet.outgoing { align-self: flex-end; }
.message-packet.incoming { align-self: flex-start; }

.packet-bubble { padding: 1rem 1.25rem; border-radius: 14px; font-size: 0.98rem; border: 1px solid var(--color-border); line-height: 1.6; position: relative; }
.outgoing .packet-bubble { background: var(--color-primary); color: white; border: none; }
.incoming .packet-bubble { background: var(--color-surface); color: var(--color-text); }
.packet-meta { font-size: 0.72rem; color: var(--color-text-muted); text-transform: uppercase; letter-spacing: 0.04em; display: flex; gap: 0.5rem; align-items: center; }
.outgoing .packet-meta { justify-content: flex-end; }

.packet-delete-btn { background: none; border: none; color: var(--color-accent); cursor: pointer; font-size: 0.7rem; font-weight: 600; padding: 0 0.25rem; opacity: 0.5; transition: var(--transition); }
.packet-delete-btn:hover { opacity: 1; color: var(--color-danger); }

.crypto-badge { display: inline-flex; align-items: center; gap: 0.35rem; font-size: 0.68rem; background: #e0efe3; color: #2e6639; padding: 0.2rem 0.5rem; border-radius: 4px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 0.5rem; }

.workspace-input-area { padding: 1.5rem; border-top: 1px solid var(--color-border); background: var(--color-surface); }
.input-row { display: flex; gap: 1rem; align-items: flex-end; }

textarea, input[type="text"], input[type="password"] { width: 100%; padding: 0.75rem 1rem; border: 1px solid var(--color-border); border-radius: 8px; font-family: var(--font-sans); font-size: 0.95rem; background-color: var(--color-surface); color: var(--color-primary); transition: var(--transition); }
textarea:focus, input[type="text"]:focus, input[type="password"]:focus { outline: none; border-color: var(--color-accent); box-shadow: 0 0 0 3px rgba(181, 101, 101, 0.1); }

.btn-primary { background: var(--color-accent); color: white; border: none; padding: 0.85rem 1.75rem; border-radius: 20px; font-weight: 500; cursor: pointer; transition: var(--transition); font-size: 0.9rem; white-space: nowrap; }
.btn-primary:hover { background: #a35454; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-danger-sm { background: transparent; border: 1px solid var(--color-border); color: var(--color-danger); padding: 0.4rem 0.8rem; border-radius: 6px; font-size: 0.78rem; font-weight: 500; cursor: pointer; transition: var(--transition); }
.btn-danger-sm:hover { background: var(--color-danger); color: white; border-color: var(--color-danger); }

.timer-container { display: none; margin-top: 1rem; text-align: center; padding: 0.5rem; background: var(--color-primary-light); border-radius: 6px; font-size: 0.85rem; color: var(--color-accent); font-weight: 600; }
.stream-loader-status { text-align: center; font-size: 0.75rem; color: var(--color-text-muted); font-style: italic; padding: 0.5rem 0; width: 100%; }

.empty-state { text-align: center; padding: 4rem 2rem; color: var(--color-text-muted); font-style: italic; font-family: var(--font-serif); font-size: 1.1rem; margin: auto; }
.global-footer { text-align: center; padding: 1.5rem; border-top: 1px solid var(--color-border); font-size: 0.75rem; color: var(--color-text-muted); background: #f4f0e6; margin-top: auto; }

/* --- MOBILE RESPONSIVE ADAPTATION MATRIX --- */
@media (max-width: 768px) {
  .header-container {
    padding: 1rem;
  }
  
  #shell-root {
    padding: 1rem;
  }

  .messenger-container {
    grid-template-columns: 1fr; /* Drop side-by-side grid structure to single column stack */
    gap: 1.5rem;
    min-height: auto;
  }

  .sidebar-panel {
    padding: 1.25rem;
  }

  .chat-workspace {
    min-height: 65vh; /* Lock height so the viewport doesn't collapse on screen keyboard popups */
  }

  .chat-stream {
    padding: 1.25rem 1rem;
  }

  .message-packet {
    max-width: 88%; /* Give chat bubbles more layout freedom on narrow viewport spaces */
  }

  .workspace-input-area {
    padding: 1rem;
  }

  .input-row {
    gap: 0.5rem;
  }

  .btn-primary {
    padding: 0.85rem 1.25rem;
  }
}