* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body, html {
    height: 100%;
    font-family: 'Noto Sans KR', sans-serif;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    /* 신뢰감을 주는 어두운 블루/네이비 계열 배경 */
    background: #0a0f1d; 
}

/* 배경 이미지 설정: 신뢰도와 테크놀로지를 상징하는 이미지 */
.bg-overlay {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background-image: url('https://images.unsplash.com/photo-1620712943543-bcc4628c9757?auto=format&fit=crop&q=80&w=1920');
    background-size: cover;
    background-position: center;
    filter: brightness(0.4);
    z-index: -1;
}

.chat-container {
    width: 90%;
    max-width: 600px;
    height: 80vh;
    background: rgba(255, 255, 255, 0.07);
    backdrop-filter: blur(15px); /* 글래스모피즘 효과 */
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 24px;
    display: flex;
    flex-direction: column;
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.5);
}

/* 헤더 디자인 */
.chat-header {
    padding: 20px;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.chat-header h1 {
    color: #fff;
    font-size: 1.2rem;
    letter-spacing: 1px;
}

.chat-header p {
    color: #4facfe;
    font-size: 0.75rem;
    margin-top: 5px;
    text-transform: uppercase;
}

.status-dot {
    width: 8px; height: 8px;
    background: #00ff88;
    border-radius: 50%;
    margin: 0 auto 10px;
    box-shadow: 0 0 10px #00ff88;
}

/* 채팅 영역 */
.chat-box {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

/* 스크롤바 커스텀 */
.chat-box::-webkit-scrollbar {
    width: 5px;
}
.chat-box::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.2);
    border-radius: 10px;
}

.message {
    display: flex;
    width: 100%;
}

.bubble {
    max-width: 80%;
    padding: 12px 18px;
    border-radius: 18px;
    font-size: 0.95rem;
    line-height: 1.5;
}

.ai { justify-content: flex-start; }
.ai .bubble {
    background: rgba(255, 255, 255, 0.15);
    color: #eee;
    border-bottom-left-radius: 4px;
}

.user { justify-content: flex-end; }
.user .bubble {
    background: linear-gradient(135deg, #00f2fe 0%, #4facfe 100%);
    color: #fff;
    border-bottom-right-radius: 4px;
    box-shadow: 0 4px 15px rgba(79, 172, 254, 0.3);
}

/* 입력 영역 */
.input-area {
    padding: 20px;
    display: flex;
    gap: 10px;
}

input {
    flex: 1;
    background: rgba(255, 255, 255, 0.1);
    border: none;
    padding: 15px 20px;
    border-radius: 15px;
    color: #fff;
    outline: none;
    transition: 0.3s;
}

input:focus {
    background: rgba(255, 255, 255, 0.2);
}

button {
    background: #4facfe;
    color: white;
    border: none;
    padding: 0 25px;
    border-radius: 15px;
    cursor: pointer;
    font-weight: bold;
    transition: 0.3s;
}

button:hover {
    background: #00f2fe;
    transform: translateY(-2px);
}

/* 모바일 대응 (반응형) */
@media (max-width: 480px) {
    .chat-container {
        width: 100%;
        height: 100%;
        border-radius: 0;
    }
}