* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Arial, sans-serif;
  background: linear-gradient(135deg, #fff5f8, #f0f9ff);
  overflow: hidden; /* ⬅️ NO SCROLL */
}

/* ================= LOGIN PAGE ================= */

.center {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.login-box {
  background: #ffffff;
  padding: 26px 22px;
  border-radius: 14px;
  width: 100%;
  max-width: 360px;
  text-align: center;
  box-shadow: 0 15px 40px rgba(0,0,0,0.1);
}

.login-logo {
  display: block;
  margin: 0 auto 14px auto; /* ⬅️ CENTER */
  max-width: 200px;
  max-height: 100px;
}

.login-box h3 {
  margin: 10px 0;
  color: #444;
}

.login-box input {
  width: 100%;
  padding: 12px;
  margin-top: 10px;
  border-radius: 8px;
  border: 1px solid #ddd;
  font-size: 15px;
}

.login-box button {
  width: 100%;
  margin-top: 14px;
  padding: 12px;
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, #ff5fa2, #ff8dc7);
  color: white;
  font-size: 15px;
  cursor: pointer;
}

.login-box button:hover {
  opacity: 0.9;
}

/* ================= HEADER ================= */

.header {
  height: 110px;
  display: flex;
  justify-content: center;
  align-items: center;
  background: #ffffff;
  border-bottom: 1px solid #eee;
}

.app-logo {
  max-width: 240px;
  max-height: 90px;
}

/* ================= APP LAYOUT ================= */

.app {
  display: flex;
  height: calc(100vh - 110px);
  overflow: hidden;
}

/* Sidebar */
.sidebar {
  width: 260px;
  background: #fff;
  border-right: 1px solid #eee;
  padding: 12px;
  overflow-y: auto;
}

.sidebar button {
  width: 100%;
  padding: 10px;
  margin-bottom: 10px;
  border-radius: 10px;
  border: none;
  background: linear-gradient(135deg, #6aa9ff, #8fd3f4);
  color: #fff;
  font-size: 14px;
  cursor: pointer;
}

.sidebar div {
  padding: 6px 4px;
  cursor: pointer;
}

/* Main */
.main {
  flex: 1;
  padding: 18px;
  display: flex;
  flex-direction: column;
  align-items: center; /* ⬅️ CENTER CHAT BOXES */
  overflow-y: auto;
}

.main input,
.main textarea,
.main button {
  width: 100%;
  max-width: 720px;
  padding: 12px;
  margin-bottom: 10px;
  border-radius: 10px;
  border: 1px solid #ddd;
  font-size: 14px;
}

.main button {
  background: linear-gradient(135deg, #7f7cff, #b09bff);
  color: white;
  border: none;
  cursor: pointer;
}

#answer {
  max-width: 720px;
  width: 100%;
  background: #f7f9ff;
  padding: 12px;
  border-radius: 10px;
  margin-top: 8px;
  white-space: pre-wrap;
}

/* ================= MOBILE ================= */

@media (max-width: 768px) {

  body {
    overflow: auto; /* mobile needs scroll */
  }

  .header {
    height: auto;
    padding: 10px 0;
  }

  .app {
    flex-direction: column;
    height: auto;
  }

  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid #eee;
  }

  .login-logo {
    max-width: 170px;
    max-height: 80px;
  }

  .app-logo {
    max-width: 200px;
    max-height: 80px;
  }
}