:root {
    --color-text: #4682B4;       /* Steel Blue: 文本、深色点缀 */
    --color-primary: #87CEEB;    /* Sky Blue: 按钮、用户气泡 */
    --color-secondary: #B0E0E6;  /* Powder Blue: 机器气泡 */
    --color-bg: #E0FFFF;         /* Light Cyan: 整体背景 */
    --color-white: #ffffff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--color-bg);
    color: var(--color-text);
    height: 100vh;
    overflow: hidden;
}

/* Page Transitions */
.page {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: opacity 0.5s ease;
}

.page.active {
    display: flex;
    opacity: 1;
}

.chat-layout.page {
    flex-direction: row;
    align-items: stretch; /* Stretch sidebar and content */
    justify-content: flex-start;
}

/* Sidebar */
.sidebar {
    width: 260px;
    background-color: rgba(255, 255, 255, 0.6);
    backdrop-filter: blur(15px);
    border-right: 1px solid rgba(70, 130, 180, 0.1);
    display: flex;
    flex-direction: column;
    padding: 20px;
    transition: transform 0.3s ease;
    z-index: 20;
}

.sidebar-title {
    margin-bottom: 20px;
    font-size: 1.2rem;
    color: var(--color-text);
    padding-left: 10px;
    border-left: 4px solid var(--color-primary);
}

.session-list {
    list-style: none;
    overflow-y: auto;
    flex: 1;
}

.session-item {
    padding: 12px 15px;
    margin-bottom: 8px;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.9rem;
    color: #555;
    background-color: rgba(255,255,255,0.5);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.session-item .delete-session-btn {
    opacity: 0;
    font-weight: bold;
    color: inherit;
    padding: 0 5px;
    border-radius: 50%;
    transition: opacity 0.2s, background-color 0.2s;
}

.session-item:hover .delete-session-btn {
    opacity: 1;
}

.session-item .delete-session-btn:hover {
    background-color: rgba(0,0,0,0.1);
    color: red;
}

.session-item:hover {
    background-color: rgba(255,255,255,0.8);
    transform: translateX(5px);
}

.session-item.active-session {
    background-color: var(--color-primary);
    color: var(--color-white);
    font-weight: bold;
    box-shadow: 0 4px 10px rgba(135, 206, 235, 0.4);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center; /* Center children horizontally */
    position: relative;
    height: 100%;
    /* remove inner paddings/margins to let wrapper fill */
}

/* Wrapper to hold chat and TV side by side */
.content-wrapper {
    flex: 1;
    display: flex;
    flex-direction: row;
    align-items: stretch;
    justify-content: center;
    width: 100%;
    max-width: 1200px;
    padding-top: 60px; /* Leave space for absolute header/button */
    box-sizing: border-box;
    min-height: 0; /* CRITICAL: Allows child containers to scroll instead of growing infinitely */
}

/* Landing Page */
.logo {
    font-size: 4rem;
    font-weight: 300;
    margin-bottom: 1rem;
    letter-spacing: 0.5rem;
    color: var(--color-text);
    animation: float 3s ease-in-out infinite;
}

.subtitle {
    font-size: 1.2rem;
    margin-bottom: 3rem;
    opacity: 0.8;
}

.btn {
    padding: 15px 40px;
    background-color: var(--color-primary);
    color: var(--color-white);
    border: none;
    border-radius: 30px;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(70, 130, 180, 0.2);
    transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(70, 130, 180, 0.3);
    background-color: #7EC0EE;
}

/* Chat Page */
.header {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 100; /* Ensure header stays on top if needed, though centered alignment usually avoids overlap */
}

.logo-small {
    font-size: 1.5rem;
    font-weight: bold;
}

/* 3D TV Robot CSS Art */
.tv-container {
    /* Fixed height for TV to prevent squishing or growing */
    flex: 0 0 300px; 
    display: flex;
    align-items: center;
    justify-content: center;
    perspective: 1000px;
    z-index: 10;
    margin-left: 20px;
}

.tv-robot {
    position: relative;
    transform-style: preserve-3d;
    animation: float-robot 6s ease-in-out infinite; /* Slower, smoother float */
}

/* Head / Main Body */
.head {
    width: 220px;
    height: 160px;
    background-color: var(--color-primary); /* Sky Blue */
    border-radius: 40px; /* Very rounded */
    padding: 15px;
    border: 6px solid #fff; /* White cartoon outline */
    box-shadow: 
        0 15px 35px rgba(70, 130, 180, 0.2),
        inset -10px -10px 0 rgba(0,0,0,0.05);
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: relative;
    z-index: 5;
}

/* Screen area */
.screen {
    flex: 1;
    height: 100%;
    background-color: #F0F8FF; /* Very light blue */
    border-radius: 25px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    box-shadow: inset 3px 3px 10px rgba(0,0,0,0.1);
    position: relative;
    border: 3px solid #E0F0F5;
    overflow: hidden;
}

/* Glare on screen */
.screen::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(135deg, rgba(255,255,255,0.4) 0%, transparent 60%);
    pointer-events: none;
}

.face {
    color: var(--color-text);
    font-size: 3rem; /* Bigger face */
    font-weight: 900;
    font-family: 'Segoe UI', sans-serif; /* Cleaner font */
    z-index: 2;
    text-shadow: 2px 2px 0px rgba(255,255,255,0.5);
    margin-bottom: 5px;
}

/* Cheeks */
.cheeks {
    position: absolute;
    width: 60%;
    top: 55%;
    display: flex;
    justify-content: space-between;
    z-index: 1;
    padding: 0 10px;
}

.cheek {
    width: 12px;
    height: 8px;
    background-color: #FFB7B2; /* Cute pink */
    border-radius: 50%;
    opacity: 0.6;
    animation: blush 3s infinite alternate;
}

@keyframes blush { from { opacity: 0.4; } to { opacity: 0.8; transform: scale(1.1); } }

/* Controls Side Panel */
.controls {
    width: 45px;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 15px;
    padding-left: 10px;
    border-left: 2px dashed rgba(255,255,255,0.5); /* Stitching detail */
}

.knob {
    width: 28px;
    height: 28px;
    background-color: #fff;
    border-radius: 50%;
    box-shadow: 0 3px 0 rgba(70, 130, 180, 0.2);
    position: relative;
    cursor: pointer;
    transition: transform 0.2s;
}

.knob::after {
    content: '';
    position: absolute;
    top: 4px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 8px;
    background-color: var(--color-text);
    border-radius: 2px;
}

.knob:hover { transform: rotate(45deg); }

.speaker-grill {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-top: 5px;
}

.speaker-grill span {
    width: 24px;
    height: 3px;
    background-color: rgba(255,255,255,0.6);
    border-radius: 2px;
}

/* Antennas (Rabbit Ears) */
.antennas {
    position: absolute;
    top: -35px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 50px;
    z-index: 1;
}

.antenna {
    position: absolute;
    bottom: 0;
    width: 6px;
    height: 50px;
    background-color: var(--color-text);
    border-radius: 5px;
}

.antenna::after {
    content: '';
    position: absolute;
    top: -8px;
    left: 50%;
    transform: translateX(-50%);
    width: 14px;
    height: 14px;
    background-color: var(--color-secondary); /* Match body accent */
    border: 2px solid var(--color-text);
    border-radius: 50%;
}

.antenna.left {
    left: 20px;
    transform: rotate(-25deg);
    animation: wiggle-left 4s ease-in-out infinite;
    height: 45px;
}

.antenna.right {
    right: 20px;
    transform: rotate(25deg);
    animation: wiggle-right 5s ease-in-out infinite 0.5s;
}

@keyframes wiggle-left { 0%,100%{transform:rotate(-25deg);} 50%{transform:rotate(-35deg);} }
@keyframes wiggle-right { 0%,100%{transform:rotate(25deg);} 50%{transform:rotate(35deg);} }

/* Neck & Body */
.body-neck {
    width: 60px;
    height: 15px;
    background-color: #ddd;
    margin: -5px auto 0;
    position: relative;
    z-index: 4;
    border-radius: 5px;
    box-shadow: inset 0 0 5px rgba(0,0,0,0.1);
}

.base-foot {
    width: 120px;
    height: 20px;
    background-color: #fff;
    border-radius: 15px;
    margin: -2px auto 0;
    box-shadow: 0 5px 15px rgba(70, 130, 180, 0.15);
    position: relative;
    z-index: 4;
    border: 2px solid #eee;
}

/* Animations */
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

@keyframes float-robot {
    0%, 100% { transform: translateY(0) rotateX(5deg); }
    50% { transform: translateY(-15px) rotateX(-5deg); }
}

/* Chat Area */
.chat-container {
    flex: 1; /* Take remaining space */
    min-height: 0; /* CRITICAL: Enables scrolling for flex children */
    width: 100%;
    max-width: 600px; /* Keep the requested width */
    background-color: rgba(255, 255, 255, 0.4);
    border-radius: 30px; /* Full radius since it's floating */
    display: flex;
    flex-direction: column;
    padding: 20px;
    backdrop-filter: blur(10px);
    box-shadow: 0 -5px 20px rgba(70, 130, 180, 0.05);
    margin-bottom: 20px; /* Give some breathing room at the bottom */
}

.chat-history {
    flex: 1;
    overflow-y: auto;
    min-height: 0; /* Critical for flex child scrolling */
    padding: 10px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

/* Custom Scrollbar */
.chat-history::-webkit-scrollbar {
    width: 8px;
}
.chat-history::-webkit-scrollbar-track {
    background: rgba(0,0,0,0.05);
    border-radius: 10px;
}
.chat-history::-webkit-scrollbar-thumb {
    background-color: var(--color-text); /* Steel Blue for visibility */
    border-radius: 10px;
    border: 2px solid transparent; /* Creates padding around thumb */
    background-clip: content-box;
}
.chat-history::-webkit-scrollbar-thumb:hover {
    background-color: #36648B;
}

.message {
    max-width: 80%;
    padding: 12px 18px;
    border-radius: 18px;
    line-height: 1.6;
    font-size: 0.95rem;
    animation: popIn 0.3s ease-out;
    word-wrap: break-word;
}

@keyframes popIn {
    from { opacity: 0; transform: scale(0.9); }
    to { opacity: 1; transform: scale(1); }
}

.bot-msg {
    align-self: flex-start;
    background-color: var(--color-secondary);
    color: #2F4F4F;
    border-bottom-left-radius: 4px;
}

.user-msg {
    align-self: flex-end;
    background-color: var(--color-primary);
    color: var(--color-white);
    border-bottom-right-radius: 4px;
}

.input-area {
    display: flex;
    gap: 10px;
    padding-top: 15px;
    border-top: 1px solid rgba(70, 130, 180, 0.1);
    flex-shrink: 0; /* Prevent input area from squishing */
}

#user-input {
    flex: 1;
    padding: 12px 20px;
    border-radius: 25px;
    border: 1px solid var(--color-secondary);
    background-color: var(--color-white);
    outline: none;
    color: var(--color-text);
    transition: box-shadow 0.2s;
}

#user-input:focus {
    box-shadow: 0 0 0 3px rgba(135, 206, 235, 0.3);
}

.btn-send {
    padding: 0 25px;
    background-color: var(--color-text);
    color: var(--color-white);
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-weight: bold;
    transition: background 0.2s;
}

.btn-send:hover {
    background-color: #36648B;
}

.btn-icon {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    border: none;
    background-color: var(--color-secondary);
    color: #2F4F4F;
    font-size: 1.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
}

.btn-icon:hover {
    background-color: var(--color-primary);
    color: var(--color-white);
    transform: rotate(90deg);
}

/* Emoticons States */
.face.thinking { animation: blink 1s infinite; }
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0.5; } }

/* Stats Button */
.stats-btn {
    position: absolute;
    top: 20px;
    right: 20px; /* Right for better balance on desktop, or left if strictly requested */
    padding: 10px 20px;
    background-color: var(--color-white);
    color: var(--color-text);
    border: none;
    border-radius: 20px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.05);
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s;
    z-index: 100;
}

.stats-btn:hover {
    background-color: var(--color-primary);
    color: var(--color-white);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 200;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.4);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: var(--color-white);
    margin: 2% auto; /* 占据较大空间 */
    padding: 30px;
    border-radius: 20px;
    width: 95%; /* 接近整个页面宽度 */
    max-width: none;
    height: 90vh; /* 接近整个页面高度 */
    display: flex;
    flex-direction: column;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    animation: slideUp 0.4s ease;
}

@keyframes slideUp {
    from { transform: translateY(50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.close-btn {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}

.close-btn:hover { color: var(--color-text); }

/* Table */
.table-container {
    margin-top: 20px;
    overflow: auto;
    flex: 1; /* 让表格容器占满剩余高度 */
}

table {
    width: 100%;
    border-collapse: collapse;
    table-layout: fixed; /* 固定列宽 */
    font-size: 0.9rem;
}

th, td {
    border: 1px solid #ddd;
    padding: 12px;
    text-align: left;
    vertical-align: top;
    word-wrap: break-word; /* 允许单词换行，适配固定宽度 */
}

/* 可以稍微指定第一列的宽度 */
th:nth-child(1) {
    width: 80px; 
}

th {
    background-color: var(--color-secondary);
    color: #2F4F4F;
    font-weight: bold;
    position: sticky;
    top: 0;
}

tr:nth-child(even) { background-color: #f9f9f9; }
tr:hover { background-color: #f1f1f1; }