/* ApsionAtlas — UI style moderne (WhatsApp/Messenger-like) */
:root {
  --bg: #0b1220;
  --bg-gradient-1: #0a1323;
  --bg-gradient-2: #0f1b33;
  --panel: #111b2e;
  --panel-2: #16243d;
  --chat: #0f182b;
  --input: #1a2a44;
  --border: #263a5a;
  --text: #e9f0fb;
  --text-muted: #9bb0d3;
  --accent: #23d3b6;
  --accent-2: #36a2ff;
  --accent-hover: #1cbfa5;
  --danger: #ff6b6b;
  --radius: 14px;
  --shadow: 0 8px 28px rgba(0, 0, 0, 0.35);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: 'Inter', 'Segoe UI', Roboto, Arial, sans-serif;
  color: var(--text);
  background: linear-gradient(135deg, var(--bg-gradient-1) 0%, var(--bg-gradient-2) 52%, var(--bg-gradient-1) 100%);
}

.hidden { display: none !important; }

/* Login */
#login-screen {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 20px;
}

.login-box {
  width: 100%;
  max-width: 420px;
  padding: 28px;
  background: linear-gradient(170deg, rgba(20,34,57,0.95), rgba(15,24,43,0.95));
  border: 1px solid var(--border);
  border-radius: 18px;
  box-shadow: var(--shadow);
}

.login-box h1 {
  margin: 0 0 6px;
  font-size: 2rem;
  letter-spacing: 0.2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.subtitle {
  margin: 0 0 20px;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.login-box input {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(19, 32, 54, 0.88);
  color: var(--text);
  font-size: 1rem;
  padding: 13px 14px;
  margin-bottom: 10px;
}

.login-box input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(35,211,182,0.18);
}

.login-box button {
  width: 100%;
  border: none;
  border-radius: 12px;
  background: linear-gradient(90deg, var(--accent), #2fd8aa);
  color: #0a1729;
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  padding: 12px 14px;
  margin-top: 4px;
}

.login-box button:hover { background: linear-gradient(90deg, var(--accent-hover), #2ec29f); }
.error { color: var(--danger); font-size: 0.92rem; margin-top: 8px; }
.hint { color: var(--text-muted); font-size: 0.82rem; margin-top: 12px; }

/* Chat layout */
#chat-screen {
  height: 100vh;
  display: grid;
  grid-template-columns: 320px 1fr;
}

.sidebar {
  background: linear-gradient(180deg, #121d32, #10192c);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.sidebar-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px;
  border-bottom: 1px solid var(--border);
}

.sidebar-header h2 {
  margin: 0;
  font-size: 1.1rem;
  font-weight: 700;
  color: #dff5ff;
  flex: 1;
}

.user-badge {
  font-size: 0.78rem;
  color: var(--text-muted);
  max-width: 140px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.icon-btn {
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  padding: 6px 8px;
  border-radius: 8px;
}

.icon-btn:hover {
  color: var(--text);
  background: rgba(255,255,255,0.06);
}

.conversations-list {
  flex: 1;
  overflow: auto;
  padding: 10px;
}

.conv-item {
  margin-bottom: 8px;
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 10px 12px;
  cursor: pointer;
  transition: 0.15s ease;
  background: rgba(21, 33, 54, 0.72);
}

.conv-item:hover {
  border-color: #2e466a;
  background: rgba(27, 42, 67, 0.95);
}

.conv-item.active {
  background: linear-gradient(90deg, rgba(35,211,182,0.18), rgba(54,162,255,0.16));
  border-color: rgba(35,211,182,0.45);
}

.conv-item .conv-name { font-weight: 600; font-size: 0.96rem; }
.conv-item .preview { font-size: 0.82rem; color: var(--text-muted); margin-top: 2px; display: block; }

.new-conv-btn {
  border: none;
  margin: 10px;
  padding: 11px 12px;
  border-radius: 12px;
  background: linear-gradient(90deg, var(--accent), #31d0f0);
  color: #082033;
  font-weight: 700;
  cursor: pointer;
}

.new-conv-btn:hover { filter: brightness(1.05); }

/* Chat area */
.chat-area {
  background: linear-gradient(180deg, rgba(11,21,38,0.9), rgba(10,18,31,0.95));
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.empty-state {
  flex: 1;
  display: grid;
  place-items: center;
  color: var(--text-muted);
  padding: 20px;
  text-align: center;
}

.active-chat {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.chat-header {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  font-weight: 700;
  color: #ebf6ff;
  background: rgba(20, 33, 54, 0.55);
  backdrop-filter: blur(8px);
}

.messages-container {
  flex: 1;
  overflow: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.msg {
  max-width: min(78%, 720px);
  border-radius: 16px;
  padding: 10px 12px 8px;
  word-break: break-word;
  position: relative;
  box-shadow: 0 3px 12px rgba(0,0,0,0.2);
}

.msg.sent {
  align-self: flex-end;
  background: linear-gradient(135deg, #24ceb2, #21b7da);
  color: #032236;
  border-bottom-right-radius: 6px;
}

.msg.received {
  align-self: flex-start;
  background: #192845;
  border: 1px solid #2b436a;
  color: #e9f0fb;
  border-bottom-left-radius: 6px;
}

.msg .msg-sender {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  opacity: 0.82;
  margin-bottom: 4px;
}

.msg .msg-content {
  display: block;
  font-size: 0.95rem;
  line-height: 1.4;
}

.msg .time {
  display: block;
  margin-top: 5px;
  font-size: 0.72rem;
  opacity: 0.8;
  text-align: right;
}

.msg a {
  color: inherit;
  text-decoration: underline;
}

.compose-area {
  border-top: 1px solid var(--border);
  padding: 10px 14px 14px;
  background: rgba(17, 27, 46, 0.95);
}

.compose-actions {
  min-height: 20px;
  margin-bottom: 6px;
}

#file-input { display: none; }

.attach-preview {
  color: var(--text-muted);
  font-size: 0.82rem;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px;
  align-items: end;
}

#message-input {
  width: 100%;
  border: 1px solid var(--border);
  background: var(--input);
  color: var(--text);
  border-radius: 14px;
  padding: 12px 13px;
  font: inherit;
  resize: none;
  min-height: 44px;
  max-height: 124px;
}

#message-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(35,211,182,0.15);
}

.send-btn {
  border: none;
  border-radius: 12px;
  background: linear-gradient(90deg, var(--accent), #2ec9f2);
  color: #07243a;
  font-weight: 700;
  padding: 11px 16px;
  cursor: pointer;
}

.send-btn:hover { filter: brightness(1.06); }

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(5, 9, 16, 0.68);
  backdrop-filter: blur(2px);
  z-index: 1000;
  display: grid;
  place-items: center;
}

.modal.hidden { display: none; }

.modal-content {
  width: min(92vw, 420px);
  max-height: 76vh;
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: linear-gradient(170deg, #132039, #101b31);
  padding: 16px;
  box-shadow: var(--shadow);
}

.modal-content h3 {
  margin: 4px 0 12px;
}

.user-picker-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 12px;
}

.user-picker-item {
  width: 100%;
  text-align: left;
  border: 1px solid var(--border);
  background: rgba(24, 39, 64, 0.9);
  color: var(--text);
  padding: 10px 12px;
  border-radius: 10px;
  cursor: pointer;
}

.user-picker-item:hover {
  border-color: rgba(35,211,182,0.5);
  background: rgba(30, 50, 82, 0.95);
}

.btn-secondary {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  border-radius: 10px;
  padding: 8px 12px;
  cursor: pointer;
}

.btn-secondary:hover { color: var(--text); }

/* Mobile */
@media (max-width: 900px) {
  #chat-screen {
    grid-template-columns: 1fr;
    grid-template-rows: 40vh 60vh;
  }

  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--border);
  }

  .chat-header { padding: 12px 14px; }
  .messages-container { padding: 12px; }
  .msg { max-width: 88%; }
}