:root {
  --bg: #0f0f12;
  --bg-2: #141826;
  --card: #1b2033;
  --accent: #f7b05b;
  --accent-2: #5ad6c4;
  --text: #e7ebf5;
  --muted: #a1acc5;
  --danger: #ff6b6b;
  --success: #6be28f;
  --shadow: 0 20px 60px rgba(0, 0, 0, 0.35);
  --radius: 18px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Trebuchet MS", "Lucida Grande", "Segoe UI", sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 600px at 10% 10%, #232844 0%, transparent 55%),
              radial-gradient(900px 500px at 90% 20%, #1a2b34 0%, transparent 50%),
              linear-gradient(135deg, var(--bg) 0%, #0b0d14 100%);
  min-height: 100vh;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.brand-badge {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent), #f06d5a);
  display: grid;
  place-items: center;
  color: #1a1a1a;
  font-weight: 800;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 12px 24px 40px;
}

.card {
  background: linear-gradient(160deg, rgba(27, 32, 51, 0.95), rgba(20, 24, 38, 0.95));
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  backdrop-filter: blur(12px);
}

.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 20px;
}

h1, h2, h3 {
  margin: 0 0 16px;
}

p {
  color: var(--muted);
}

input, select, textarea, button {
  font: inherit;
}

input, select, textarea {
  width: 100%;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: rgba(10, 12, 20, 0.7);
  color: var(--text);
  outline: none;
}

button {
  border: none;
  padding: 12px 16px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent), #f06d5a);
  color: #1a1a1a;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 20px rgba(247, 176, 91, 0.35);
}

button.secondary {
  background: linear-gradient(135deg, var(--accent-2), #6ba9ff);
  color: #062027;
}

button.ghost {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.12);
  color: var(--text);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
  background: rgba(90, 214, 196, 0.18);
  color: var(--accent-2);
}

.notice {
  padding: 12px 14px;
  border-radius: 12px;
  background: rgba(255, 107, 107, 0.15);
  color: #ffb5b5;
  margin-top: 12px;
}

.success {
  background: rgba(107, 226, 143, 0.15);
  color: #b7f5c8;
}

.layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 18px;
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.list-item {
  padding: 12px 14px;
  border-radius: 12px;
  background: rgba(10, 12, 20, 0.55);
  cursor: pointer;
  transition: background 0.2s ease;
}

.list-item.active {
  background: rgba(90, 214, 196, 0.18);
  border: 1px solid rgba(90, 214, 196, 0.4);
}

.chat-window {
  display: flex;
  flex-direction: column;
  min-height: 70vh;
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding-right: 8px;
}

.message {
  padding: 12px 14px;
  border-radius: 14px;
  max-width: 70%;
  background: rgba(10, 12, 20, 0.7);
  text-align: right;
}

.message.me {
  margin-left: auto;
  background: rgba(90, 214, 196, 0.2);
  border: 1px solid rgba(90, 214, 196, 0.4);
}

.message-meta {
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 6px;
}

.message-file {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.controls {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: 10px;
  margin-top: 14px;
}

input[type="file"] {
  padding: 10px;
}

.badge {
  font-size: 12px;
  color: #1a1a1a;
  background: var(--accent);
  padding: 4px 10px;
  border-radius: 999px;
  font-weight: 700;
}

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    order: 2;
  }

  .chat-window {
    min-height: 55vh;
  }

  .message {
    max-width: 85%;
  }

  header {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .page-login .grid > .card {
    grid-column: span 12;
  }
}

@media (max-width: 520px) {
  .controls {
    grid-template-columns: 1fr;
  }

  .container {
    padding: 12px 16px 30px;
  }
}