:root {
    --pink-50: #fff7f8;
    --pink-100: #fdecee;
    --pink-200: #f8dfe3;
    --pink-300: #f4c4cd;
    --pink-400: #e4a1b3;
    --pink-500: #c08497;
    --accent: #d46a8a;
    --glass: rgba(255, 255, 255, 0.75);
    --glass-border: rgba(255, 182, 193, 0.3);
}

/* Glassmorphism */
.glass {
    background: var(--glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px rgba(192, 132, 151, 0.15);
}

/* Particles container */
#particles-js {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
    opacity: 0.6;
    transition: opacity 0.6s;
}

/* Mode switch */
.mode-switch {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 12px;
    color: var(--pink-500);
    margin-left: auto;
}

.switch {
    position: relative;
    display: inline-block;
    width: 42px;
    height: 24px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: #ccc;
    transition: .4s;
    border-radius: 24px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked+.slider {
    background: var(--accent);
}

input:checked+.slider:before {
    transform: translateX(18px);
}

/* Rich mode enhancements */
body.rich-mode #messages .msg-bot,
body.rich-mode #messages .msg-user {
    box-shadow: 0 10px 30px rgba(192, 132, 151, 0.25);
    transform: translateY(2px);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

body.rich-mode #messages .msg-bot:hover,
body.rich-mode #messages .msg-user:hover {
    transform: translateY(-4px) scale(1.02);
}

/* 3D tilt nhẹ cho avatar và bubbles */
.msg {
    transition: transform 0.3s ease;
}

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

body {
    font-family: 'Be Vietnam Pro', sans-serif;
    background: var(--pink-50);
    color: var(--text);
    height: 100vh;
    display: flex;
    overflow: hidden;
}

/* ── SIDEBAR ── */
#sidebar {
    width: var(--sidebar-w);
    min-width: var(--sidebar-w);
    background: var(--pink-100);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    transition: transform .25s ease;
}

#sidebar h2 {
    font-size: 13px;
    font-weight: 600;
    color: var(--pink-500);
    padding: 18px 16px 10px;
}

#btn-new-chat {
    margin: 0 10px 10px;
    border-radius: 10px;
    background: var(--pink-300);
    border: none;
    color: var(--text);
    font-family: inherit;
    font-size: 13px;
    padding: 9px;
    cursor: pointer;
    transition: background .2s;
}

#btn-new-chat:hover {
    background: var(--pink-400);
}

#history {
    flex: 1;
    overflow-y: auto;
    padding: 6px 10px;
}

.hist-item {
    padding: 7px 9px;
    border-radius: 7px;
    font-size: 12.5px;
    cursor: pointer;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    transition: background .15s;
}

.hist-item:hover {
    background: var(--pink-200);
}

/* ── CHAT ── */
#chat-wrap {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

#chat-header {
    padding: 14px 18px;
    background: #fff;
    border-bottom: 1px solid var(--border);
    font-weight: 600;
    font-size: 15px;
    line-height: 1.4;
}

#chat-header small {
    display: block;
    font-size: 11.5px;
    font-weight: 400;
    color: var(--pink-500);
}

#messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px 20px 10px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

/* ── WELCOME SCREEN ── */
#welcome {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex: 1;
    padding: 28px 20px;
    text-align: center;
    overflow-y: auto;
}

#welcome .avatar {
    font-size: 52px;
    margin-bottom: 10px;
    line-height: 1;
}

#welcome h3 {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 4px;
}

#welcome p {
    font-size: 13px;
    color: var(--pink-500);
    margin-bottom: 22px;
}

.topic-group {
    width: 100%;
    max-width: 560px;
    margin-bottom: 14px;
    text-align: left;
}

.topic-label {
    font-size: 11px;
    font-weight: 600;
    color: var(--pink-500);
    text-transform: uppercase;
    letter-spacing: .6px;
    margin-bottom: 7px;
    padding-left: 2px;
}

.sample-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 7px;
}

.sample-btn {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 9px 12px;
    font-size: 12.5px;
    font-family: inherit;
    color: var(--text);
    cursor: pointer;
    text-align: left;
    transition: background .15s, border-color .15s;
    line-height: 1.4;
}

.sample-btn:hover {
    background: var(--pink-100);
    border-color: var(--pink-400);
}

/* ── MESSAGES ── */
.msg {
    max-width: 80%;
    padding: 11px 15px;
    border-radius: 14px;
    font-size: 13.5px;
    line-height: 1.6;
    white-space: pre-line;
    animation: fadeUp .2s ease both;
}

@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(6px);
    }

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

.msg-user {
    background: var(--pink-300);
    align-self: flex-end;
    max-width: 80%;
    /* user message cũng có thể lên tới 80% */
}

.msg-bot {
    background: #fff;
    border: 1px solid var(--border);
    align-self: flex-start;
    max-width: 80%;
    /* bot message cũng vậy */
}

.msg-bot.thinking {
    color: var(--pink-500);
    font-style: italic;
}

.sources-wrap {
    align-self: flex-start;
    max-width: 80%;
    /* tăng từ 68% lên 80% */
    width: 100%;
}

.sources-toggle {
    font-size: 11px;
    color: var(--pink-500);
    cursor: pointer;
    background: none;
    border: none;
    padding: 2px 0 6px;
    font-family: inherit;
}

.sources-body {
    font-size: 11px;
    background: var(--pink-50);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 8px 12px;
    line-height: 1.7;
}

.suggest-wrap {
    align-self: flex-start;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    max-width: 85%;
    /* tăng từ 80% lên 85% */
}

.suggest-btn {
    font-size: 11.5px;
    padding: 5px 11px;
    border-radius: 20px;
    background: var(--pink-200);
    border: 1px solid var(--border);
    color: var(--text);
    cursor: pointer;
    font-family: inherit;
    transition: background .15s;
}

.suggest-btn:hover {
    background: var(--pink-300);
}

/* ── INPUT ── */
#input-area {
    padding: 12px 14px;
    background: #fff;
    border-top: 1px solid var(--border);
    display: flex;
    gap: 8px;
    align-items: center;
}

#user-input {
    flex: 1;
    padding: 10px 14px;
    border-radius: 22px;
    border: 1px solid var(--border);
    font-family: inherit;
    font-size: 13.5px;
    color: var(--text);
    outline: none;
    background: var(--pink-50);
    transition: border-color .2s;
}

#user-input:focus {
    border-color: var(--pink-400);
}

#btn-send {
    padding: 9px 16px;
    border-radius: 22px;
    background: var(--pink-300);
    border: none;
    font-size: 16px;
    cursor: pointer;
    transition: background .2s;
    line-height: 1;
}

#btn-send:hover {
    background: var(--pink-400);
}

#btn-send:disabled {
    opacity: .5;
    cursor: not-allowed;
}

/* ── MOBILE ── */
#btn-toggle-sidebar {
    display: none;
    background: none;
    border: none;
    font-size: 20px;
    cursor: pointer;
    padding: 0 10px 0 0;
}

@media (max-width: 640px) {
    #btn-toggle-sidebar {
        display: inline-block;
    }

    #sidebar {
        position: fixed;
        top: 0;
        left: 0;
        height: 100%;
        z-index: 200;
        transform: translateX(-100%);
    }

    #sidebar.open {
        transform: translateX(0);
    }

    .sample-grid {
        grid-template-columns: 1fr;
    }
}

/* Sidebar: session active */
.hist-item.active {
    background: var(--pink-300);
    font-weight: 600;
}

/* Sidebar: khi chưa có lịch sử */
.hist-empty {
    padding: 12px 10px;
    font-size: 12px;
    color: var(--pink-500);
    text-align: center;
}

/* ── Thêm vào cuối style.css ── */

/* Sidebar: session active */
.hist-item.active {
    background: var(--pink-300);
    font-weight: 600;
}

/* Sidebar: khi chưa có lịch sử */
.hist-empty {
    padding: 12px 10px;
    font-size: 12px;
    color: var(--pink-500);
    text-align: center;
}

/* Sidebar: layout item có nút xóa */
.hist-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.hist-title {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    cursor: pointer;
}

/* Nút ✕ xóa từng session */
.hist-del {
    flex-shrink: 0;
    background: none;
    border: none;
    color: var(--pink-400);
    font-size: 11px;
    padding: 2px 4px;
    border-radius: 4px;
    cursor: pointer;
    opacity: 0;
    transition: opacity .15s, background .15s;
    line-height: 1;
}

.hist-item:hover .hist-del {
    opacity: 1;
}

.hist-del:hover {
    background: var(--pink-300);
    color: var(--accent);
}

/* Nút xóa tất cả ở cuối sidebar */
.hist-clear-all {
    display: block;
    width: calc(100% - 20px);
    margin: 8px 10px 10px;
    padding: 7px;
    background: none;
    border: 1px dashed var(--pink-400);
    border-radius: 8px;
    color: var(--pink-500);
    font-size: 11.5px;
    font-family: inherit;
    cursor: pointer;
    transition: background .15s, color .15s;
}

.hist-clear-all:hover {
    background: var(--pink-200);
    color: var(--accent);
}