/* -------------------------------------------------------------
   CalculatorNan - Web Realtime Chat Stylesheet
   Theme: Minimalist Monochromatic (Đen Trắng Tối Giản)
   Design: Clean High-Contrast Black & White with Sharp Typography
------------------------------------------------------------- */
:root {
    --bg-main: #000000;
    --bg-sidebar: #09090B;
    --bg-card: #121216;
    --bg-card-border: rgba(255, 255, 255, 0.14);
    --bg-card-hover: #1A1A22;
    --mono-white: #FFFFFF;
    --mono-offwhite: #F4F4F5;
    --mono-gray-light: #E4E4E7;
    --mono-gray-mid: #A1A1AA;
    --mono-gray-dark: #27272A;
    --mono-border: #27272A;
    --radius-lg: 14px;
    --radius-md: 10px;
    --radius-sm: 6px;
    --font-family: 'Outfit', -apple-system, BlinkMacSystemFont, 'SF Pro Display', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: var(--font-family);
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg-main);
    color: var(--mono-white);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

/* App Container */
.app-container {
    width: 100vw;
    height: 100vh;
    display: flex;
    background: var(--bg-main);
}

/* Sidebar Navigation */
.sidebar {
    width: 360px;
    height: 100%;
    background: var(--bg-sidebar);
    border-right: 1px solid var(--bg-card-border);
    display: flex;
    flex-direction: column;
    z-index: 10;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.sidebar-header {
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--bg-card-border);
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-icon {
    width: 38px;
    height: 38px;
    background: var(--mono-white);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #000;
}

.brand-info h2 {
    font-size: 17px;
    font-weight: 700;
    color: var(--mono-white);
    letter-spacing: 0.5px;
}

.badge-web {
    font-size: 9px;
    font-weight: 700;
    color: #000;
    background: var(--mono-white);
    padding: 2px 6px;
    border-radius: 4px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* My ID Card */
.my-id-card {
    margin: 16px 20px;
    padding: 16px;
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.id-meta {
    display: flex;
    flex-direction: column;
}

.id-label {
    font-size: 9px;
    font-weight: 700;
    color: var(--mono-gray-mid);
    letter-spacing: 1px;
}

.id-value {
    font-size: 22px;
    font-weight: 800;
    color: var(--mono-white);
    letter-spacing: 2px;
    margin-top: 2px;
}

.btn-copy {
    background: var(--mono-white);
    color: #000;
    border: none;
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 11px;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: all 0.15s ease;
}

.btn-copy:hover {
    background: var(--mono-gray-light);
    transform: translateY(-1px);
}

/* Chat List Header */
.chat-list-header {
    padding: 12px 20px 8px;
    font-size: 10px;
    font-weight: 700;
    color: var(--mono-gray-mid);
    letter-spacing: 1.2px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.count-badge {
    background: var(--mono-darkgray);
    color: var(--mono-white);
    padding: 2px 8px;
    border-radius: 10px;
    font-size: 10px;
}

/* Chat List */
.chat-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.chat-item {
    padding: 12px 14px;
    border-radius: var(--radius-md);
    background: transparent;
    border: 1px solid transparent;
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    transition: all 0.15s ease;
}

.chat-item:hover {
    background: var(--bg-card-hover);
    border-color: var(--bg-card-border);
}

.chat-item.active {
    background: var(--mono-white);
    color: #000;
}

.chat-item.active .peer-details h4,
.chat-item.active .peer-details p {
    color: #000;
}

.chat-item.active .peer-avatar {
    background: #000;
    color: #fff;
    border-color: #000;
}

.chat-item-main {
    display: flex;
    align-items: center;
    gap: 12px;
    overflow: hidden;
}

.peer-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--mono-white);
    flex-shrink: 0;
}

.peer-details {
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.peer-details h4 {
    font-size: 14px;
    font-weight: 700;
    color: var(--mono-white);
    letter-spacing: 0.5px;
}

.peer-details p {
    font-size: 12px;
    color: var(--mono-gray-mid);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-top: 2px;
}

.btn-delete-chat {
    background: transparent;
    border: none;
    color: var(--mono-gray-mid);
    padding: 6px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    opacity: 0;
    transition: all 0.15s ease;
}

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

.btn-delete-chat:hover {
    color: #FF4D4D;
    background: rgba(255, 77, 77, 0.1);
}

.empty-chats {
    padding: 40px 20px;
    text-align: center;
    color: var(--mono-gray-mid);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

.empty-chats svg {
    opacity: 0.4;
}

.empty-chats p {
    font-size: 13px;
    font-weight: 600;
    color: var(--mono-white);
}

.empty-chats span {
    font-size: 11px;
}

/* Sidebar Footer Branding */
.sidebar-footer {
    padding: 14px 20px;
    border-top: 1px solid var(--bg-card-border);
    font-size: 11px;
    color: var(--mono-gray-mid);
    text-align: center;
}

.sidebar-footer strong {
    color: var(--mono-white);
    letter-spacing: 0.5px;
}

/* Chat Area Main */
.chat-area {
    flex: 1;
    height: 100%;
    display: flex;
    flex-direction: column;
    background: var(--bg-main);
    position: relative;
}

/* No Chat Selected Screen */
.no-chat-selected {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    padding: 40px 20px 20px;
}

.placeholder-content {
    text-align: center;
    max-width: 400px;
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: auto 0;
}

.placeholder-icon {
    width: 80px;
    height: 80px;
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--mono-white);
    margin-bottom: 20px;
}

.placeholder-content h3 {
    font-size: 20px;
    font-weight: 700;
    color: var(--mono-white);
    margin-bottom: 8px;
}

.placeholder-content p {
    font-size: 13px;
    color: var(--mono-gray-mid);
    line-height: 1.5;
    margin-bottom: 24px;
}

.main-footer {
    font-size: 12px;
    color: var(--mono-gray-mid);
    text-align: center;
    letter-spacing: 0.5px;
}

.main-footer strong {
    color: var(--mono-white);
}

/* Buttons */
.btn-primary {
    background: var(--mono-white);
    color: #000;
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.15s ease;
}

.btn-primary:hover {
    background: var(--mono-gray-light);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--mono-darkgray);
    color: var(--mono-white);
    border: none;
    padding: 12px 20px;
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s ease;
}

.btn-secondary:hover {
    background: #3F3F46;
}

.btn-icon {
    background: transparent;
    border: none;
    color: var(--mono-gray-mid);
    padding: 8px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s ease;
}

.btn-icon:hover {
    color: var(--mono-white);
    background: var(--bg-card-hover);
}

/* Active Chat Screen */
.active-chat-wrapper {
    flex: 1;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.chat-header {
    height: 66px;
    padding: 0 24px;
    background: var(--bg-sidebar);
    border-bottom: 1px solid var(--bg-card-border);
    display: flex;
    align-items: center;
    gap: 14px;
}

.btn-back-mobile {
    display: none;
    background: transparent;
    border: none;
    color: var(--mono-white);
    cursor: pointer;
}

.chat-peer-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--mono-white);
}

.chat-peer-info {
    flex: 1;
}

.chat-peer-info h4 {
    font-size: 15px;
    font-weight: 700;
    color: var(--mono-white);
    letter-spacing: 1px;
}

.status-indicator {
    font-size: 11px;
    color: var(--mono-gray-mid);
    font-weight: 500;
}

/* Messages Container */
.messages-container {
    flex: 1;
    padding: 24px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
    background: var(--bg-main);
}

.message-bubble {
    max-width: 65%;
    display: flex;
    flex-direction: column;
}

.message-bubble.me {
    align-self: flex-end;
}

.message-bubble.peer {
    align-self: flex-start;
}

.message-content {
    padding: 12px 18px;
    border-radius: 16px;
    font-size: 14px;
    line-height: 1.45;
    word-break: break-word;
}

.message-bubble.me .message-content {
    background: var(--mono-white);
    color: #000;
    font-weight: 500;
    border-bottom-right-radius: 2px;
}

.message-bubble.peer .message-content {
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    color: var(--mono-white);
    border-bottom-left-radius: 2px;
}

.message-time {
    font-size: 10px;
    color: var(--mono-gray-mid);
    margin-top: 4px;
    padding: 0 2px;
}

.message-bubble.me .message-time {
    text-align: right;
}

/* Message Input Form */
.message-input-area {
    padding: 16px 24px;
    background: var(--bg-sidebar);
    border-top: 1px solid var(--bg-card-border);
    display: flex;
    align-items: center;
    gap: 12px;
}

.message-input-area input {
    flex: 1;
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    padding: 12px 18px;
    border-radius: 24px;
    color: var(--mono-white);
    font-size: 14px;
    outline: none;
    transition: all 0.15s ease;
}

.message-input-area input:focus {
    border-color: var(--mono-white);
}

.btn-send {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--mono-white);
    border: none;
    color: #000;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.15s ease;
}

.btn-send:hover {
    background: var(--mono-gray-light);
    transform: scale(1.05);
}

/* Modal Overlay */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 1;
    transition: opacity 0.15s ease;
}

.modal-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.modal-card {
    width: 400px;
    background: var(--bg-sidebar);
    border: 1px solid var(--bg-card-border);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.8);
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.modal-header h3 {
    font-size: 17px;
    font-weight: 700;
    color: var(--mono-white);
}

.btn-close {
    background: transparent;
    border: none;
    color: var(--mono-gray-mid);
    font-size: 24px;
    cursor: pointer;
}

.modal-desc {
    font-size: 13px;
    color: var(--mono-gray-mid);
    line-height: 1.4;
    margin-bottom: 16px;
}

.input-group input {
    width: 100%;
    background: var(--bg-card);
    border: 1px solid var(--bg-card-border);
    padding: 12px 16px;
    border-radius: var(--radius-md);
    color: var(--mono-white);
    font-size: 15px;
    letter-spacing: 1px;
    outline: none;
}

.input-group input:focus {
    border-color: var(--mono-white);
}

.error-text {
    font-size: 12px;
    color: #FF4D4D;
    margin-top: 8px;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 24px;
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 1000;
}

.toast {
    background: var(--mono-white);
    color: #000;
    padding: 12px 20px;
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 700;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    animation: slideUp 0.25s ease forwards;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hidden {
    display: none !important;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-donate-head {
    background: var(--mono-white);
    color: #000;
    border: none;
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 11px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.15s ease;
}

.btn-donate-head:hover {
    background: var(--mono-gray-light);
    transform: translateY(-1px);
}

.qr-box {
    margin: 16px 0;
    padding: 12px;
    background: #FFFFFF;
    border-radius: var(--radius-md);
    display: inline-block;
}

.qr-img {
    width: 200px;
    height: 200px;
    object-fit: contain;
    display: block;
}

.bank-details {
    font-size: 13px;
    color: var(--mono-white);
    background: var(--bg-card);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--bg-card-border);
    margin-top: 10px;
}

.text-center { text-align: center; }
.justify-center { justify-content: center !important; }