:root {
  color-scheme: dark;
  --bg: #020406;
  --bg-soft: #071013;
  --panel: rgba(5, 12, 16, 0.72);
  --panel-strong: rgba(7, 18, 22, 0.88);
  --line: rgba(136, 246, 255, 0.16);
  --line-strong: rgba(155, 255, 211, 0.28);
  --text: #edf7f8;
  --muted: #91a4aa;
  --dim: #5d737a;
  --cyan: #42e7ff;
  --green: #9cff6a;
  --shadow: rgba(0, 0, 0, 0.56);
  --radius: 8px;
  --font-size: 13px;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  font-family: 'Inter', ui-sans-serif, system-ui, -apple-system, sans-serif;
  font-size: var(--font-size);
  color: var(--text);
}

/* Subtle matrix grid overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 64px 64px;
  opacity: 0.35;
  pointer-events: none;
}

/* ========== LAYOUT ========== */
#app {
  display: flex;
  height: 100vh;
  overflow: hidden;
  position: relative;
}

/* ========== SIDEBAR (desktop + mobile slide-out) ========== */
#sidebar {
  position: fixed;
  top: 0;
  left: -280px;
  width: 260px;
  height: 100%;
  background: var(--panel-strong);
  backdrop-filter: blur(18px);
  border-right: 1px solid var(--line);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 24px;
  transition: left 0.2s ease;
  z-index: 100;
  overflow-y: auto;
}

#sidebar.open {
  left: 0;
  box-shadow: 2px 0 20px rgba(0, 0, 0, 0.5);
}

/* desktop: show sidebar always */
@media (min-width: 769px) {
  #sidebar {
    position: static;
    left: 0;
    width: 260px;
    transition: none;
  }
  #hamburger {
    display: none;
  }
}

/* sidebar sections */
.section-title {
  font-size: 11px;
  text-transform: uppercase;
  color: var(--dim);
  margin-bottom: 8px;
  letter-spacing: 0.06em;
}

#chat-list, #skills-list, #objectives-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

#chat-list div,
#skills-list label,
#objectives-list label {
  padding: 6px 8px;
  border-radius: var(--radius);
  background: var(--panel);
  border: 1px solid var(--line);
  cursor: pointer;
  transition: all 0.1s;
}

#chat-list div:hover,
#skills-list label:hover,
#objectives-list label:hover {
  background: rgba(66, 231, 255, 0.08);
  border-color: var(--line-strong);
}

#new-chat {
  margin-top: 8px;
  padding: 6px 8px;
  border-radius: var(--radius);
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--text);
  cursor: pointer;
}

/* ========== MAIN CHAT AREA ========== */
#chat-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
}

/* ========== HEADER ========== */
#chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  background: var(--panel-strong);
  backdrop-filter: blur(18px);
  flex-shrink: 0;
}

#model-select {
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--text);
  padding: 4px 6px;
  border-radius: var(--radius);
  font-size: var(--font-size);
}

#chat-title {
  font-weight: 600;
  color: var(--cyan);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Online indicator */
.online-indicator {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11px;
  color: var(--muted);
}
.pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0 0 rgba(156, 255, 106, 0.4);
  animation: pulse-ring 1.5s infinite;
}
.pulse.off {
  background: #5d737a;
  box-shadow: none;
  animation: none;
}
@keyframes pulse-ring {
  0% { box-shadow: 0 0 0 0 rgba(156, 255, 106, 0.4); }
  70% { box-shadow: 0 0 0 6px rgba(156, 255, 106, 0); }
  100% { box-shadow: 0 0 0 0 rgba(156, 255, 106, 0); }
}

/* ========== MESSAGES ========== */
#messages {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.message {
  max-width: 85%;
  padding: 8px 12px;
  border-radius: 18px;
  background: var(--panel);
  border: 1px solid var(--line);
  white-space: pre-wrap;
  line-height: 1.45;
  position: relative;
  word-wrap: break-word;
}

.message.user {
  align-self: flex-end;
  border-color: var(--cyan);
  background: rgba(66, 231, 255, 0.08);
}

.message.assistant {
  align-self: flex-start;
  border-color: var(--green);
}

.message.deleted {
  opacity: 0.5;
  filter: grayscale(0.2);
  text-decoration: line-through;
}

.message-footer {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 8px;
  margin-top: 4px;
  font-size: 10px;
  color: var(--dim);
}

.timestamp {
  font-size: 10px;
  font-family: monospace;
}

.pin-icon {
  font-size: 10px;
  cursor: default;
}

/* ========== CONTEXT MENU ========== */
.context-menu {
  background: var(--panel-strong);
  backdrop-filter: blur(18px);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 4px 0;
  min-width: 120px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
  z-index: 1000;
}

.context-item {
  padding: 6px 12px;
  cursor: pointer;
  transition: background 0.1s;
  color: var(--text);
  font-size: 12px;
}

.context-item:hover {
  background: rgba(66, 231, 255, 0.12);
}

/* ========== INPUT AREA ========== */
#input-area {
  display: flex;
  gap: 8px;
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  background: var(--panel-strong);
  backdrop-filter: blur(18px);
  flex-shrink: 0;
}

#message-input {
  flex: 1;
  padding: 8px 10px;
  border-radius: var(--radius);
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--text);
  font-size: var(--font-size);
}

#send-btn {
  padding: 8px 12px;
  border-radius: var(--radius);
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--text);
  cursor: pointer;
  transition: all 0.1s;
}

#send-btn:hover {
  background: rgba(66, 231, 255, 0.08);
  border-color: var(--line-strong);
}

/* ========== MOBILE SPECIFIC ========== */
@media (max-width: 768px) {
  #hamburger {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    background: var(--panel);
    border: 1px solid var(--line);
    border-radius: 6px;
    cursor: pointer;
    font-size: 18px;
    margin-right: 8px;
  }
  #chat-header {
    padding: 8px 12px;
  }
  .message {
    max-width: 90%;
  }
  #messages {
    padding: 12px;
  }
  #input-area {
    padding: 8px 12px;
  }
}

/* ========== UTILITIES ========== */
button, .context-item, #chat-list div, #skills-list label, #objectives-list label {
  user-select: none;
}