:root {
    --bg-dark: #0f172a;
    --primary-gradient: linear-gradient(135deg, #3b82f6, #8b5cf6);
    --secondary-gradient: linear-gradient(135deg, #10b981, #059669);
    --glass-bg: rgba(30, 41, 59, 0.6);
    --glass-border: rgba(255, 255, 255, 0.08);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --message-bot-bg: rgba(51, 65, 85, 0.7);
    --message-user-bg: var(--primary-gradient);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-dark);
    background-image: url('hcmut_bg.jpg');
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    color: var(--text-primary);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    position: relative;
}

/* Dark overlay phủ lên ảnh nền để tăng tương phản */
body::before {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(5, 10, 25, 0.72);
    backdrop-filter: blur(2px);
    -webkit-backdrop-filter: blur(2px);
    z-index: 1;
}

/* Không dùng blobs nữa, đã chuyển sang ảnh nền HCMUT */

/* --- Glassmorphism Main Container --- */
.chat-container {
    width: 95%;
    max-width: 1000px;
    height: 90vh;
    background: transparent;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
    border: none;
    border-radius: 28px;
    display: flex;
    flex-direction: column;
    z-index: 10;
    box-shadow: none;
    overflow: hidden;
}

/* --- Header Section --- */
.chat-header {
    padding: 24px 30px;
    background: transparent;
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.header-content {
    display: flex;
    align-items: center;
    gap: 18px;
}

.bot-avatar {
    width: 58px;
    height: 58px;
    border-radius: 16px;
    background: #ffffff;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 8px 24px -4px rgba(0, 80, 200, 0.45);
    padding: 6px;
    flex-shrink: 0;
}

.bot-avatar img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.header-titles h1 {
    font-size: 1.4rem;
    font-weight: 700;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 4px;
}

.header-titles p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 500;
}

.online-dot {
    display: inline-block;
    width: 8px;
    height: 8px;
    background-color: #10b981;
    border-radius: 50%;
    box-shadow: 0 0 10px #10b981, 0 0 20px #10b981;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
    70% { transform: scale(1); box-shadow: 0 0 0 8px rgba(16, 185, 129, 0); }
    100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

/* --- Chat Box Section --- */
.chat-box {
    flex: 1;
    padding: 30px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 24px;
    scroll-behavior: smooth;
}

/* Custom Webkit Scrollbar */
.chat-box::-webkit-scrollbar {
    width: 8px;
}
.chat-box::-webkit-scrollbar-track {
    background: transparent;
}
.chat-box::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.15);
    border-radius: 10px;
}
.chat-box::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.25);
}

.message {
    display: flex;
    max-width: 80%;
    animation: messageSlideIn 0.4s cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
    opacity: 0;
    transform: translateY(20px);
}

@keyframes messageSlideIn {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.bot-message {
    align-self: flex-start;
}

.user-message {
    align-self: flex-end;
}

.message-content {
    padding: 18px 24px;
    border-radius: 24px;
    font-size: 1.05rem;
    line-height: 1.7;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
    word-wrap: break-word;
}

.bot-message .message-content {
    background: rgba(15, 23, 42, 0.55);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-bottom-left-radius: 6px;
    color: #e2e8f0;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.user-message .message-content {
    background: var(--message-user-bg);
    border-bottom-right-radius: 6px;
    color: white;
}

/* Markdown Formats inside Message */
.message-content ul, .message-content ol {
    margin-left: 24px;
    margin-top: 10px;
    margin-bottom: 10px;
}

.message-content li {
    margin-bottom: 4px;
}

.message-content p {
    margin-bottom: 12px;
}
.message-content p:last-child {
    margin-bottom: 0;
}

.message-content strong {
    color: #fff;
    font-weight: 700;
}

/* --- Input Section --- */
.chat-footer {
    padding: 24px 30px;
    background: transparent;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
}

#chat-form {
    display: flex;
    gap: 16px;
    position: relative;
    width: 100%;
}

#user-input {
    flex: 1;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    padding: 18px 24px;
    padding-right: 70px; /* Space for the floating button */
    color: var(--text-primary);
    font-size: 1.05rem;
    font-family: inherit;
    transition: all 0.3s ease;
    outline: none;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.1);
}

#user-input::placeholder {
    color: var(--text-secondary);
}

#user-input:focus {
    background: rgba(255, 255, 255, 0.1);
    border-color: #3b82f6;
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.2);
}

#user-input:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

#send-btn {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    width: 48px;
    height: 48px;
    border-radius: 14px;
    border: none;
    background: var(--primary-gradient);
    color: white;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.2s ease;
}

#send-btn:hover {
    transform: translateY(-50%) scale(1.05);
    box-shadow: 0 8px 16px rgba(59, 130, 246, 0.4);
}

#send-btn:active {
    transform: translateY(-50%) scale(0.95);
}

#send-btn:disabled {
    filter: grayscale(1);
    cursor: not-allowed;
    transform: translateY(-50%) scale(1);
}

#send-btn span {
    font-size: 24px;
    margin-left: 4px; /* Fix offset for the send icon slightly */
}

/* --- Animations & Loading --- */
.typing-indicator {
    display: flex;
    gap: 8px;
    padding: 6px 4px;
}

.dot {
    width: 10px;
    height: 10px;
    background-color: var(--text-secondary);
    border-radius: 50%;
    animation: typing 1.4s infinite ease-in-out both;
}

.dot:nth-child(1) { animation-delay: -0.32s; }
.dot:nth-child(2) { animation-delay: -0.16s; }

@keyframes typing {
    0%, 80%, 100% { transform: scale(0); opacity: 0.5;}
    40% { transform: scale(1); opacity: 1; background-color: #3b82f6;}
}