:root {
    --accent-color: #38bdf8;
    --accent-hover: #7dd3fc;
    --accent-glow: rgba(56, 189, 248, 0.3);
    --danger: #ef4444;
    --success: #22c55e;
    --transition-speed: 0.2s;
}

:root {
    --bg-color: #f8fafc;
    --bg-dark: #f1f5f9;
    --card-bg: rgba(255, 255, 255, 0.8);
    --text-color: #0f172a;
    --text-muted: #64748b;
    --text-dim: #94a3b8;
    --glass-bg: rgba(241, 245, 249, 0.8);
    --input-bg: #ffffff;
    --input-border: #e2e8f0;
    --hover-bg: rgba(56, 189, 248, 0.1);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #0f172a;
        --bg-dark: #0b1120;
        --card-bg: rgba(30, 41, 59, 0.7);
        --text-color: #f8fafc;
        --text-muted: #94a3b8;
        --text-dim: #64748b;
        --glass-bg: rgba(15, 23, 42, 0.8);
        --input-bg: #1e293b;
        --input-border: rgba(255, 255, 255, 0.08);
        --hover-bg: rgba(56, 189, 248, 0.08);
    }
}

* {
    box-sizing: border-box;
    transition: background-color var(--transition-speed), color var(--transition-speed), transform var(--transition-speed), box-shadow var(--transition-speed);
}

body {
    font-family: 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    background-image: 
        radial-gradient(circle at 0% 0%, var(--hover-bg) 0%, transparent 50%),
        radial-gradient(circle at 100% 100%, rgba(168, 85, 247, 0.05) 0%, transparent 50%);
    color: var(--text-color);
    margin: 0;
    display: flex;
    justify-content: center;
    min-height: 100vh;
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: 1200px;
    padding: 2rem;
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.app-header {
    text-align: center;
    margin-bottom: 4rem;
}

h1 {
    font-size: 3.5rem;
    margin: 0;
    font-weight: 800;
    letter-spacing: -2px;
    background: linear-gradient(to right, var(--text-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

#setup-section {
    display: flex;
    justify-content: center;
}

.setup-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    width: 100%;
    max-width: 900px;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    padding: 2rem;
    border-radius: 1.5rem;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
    position: relative;
    overflow: hidden;
}

.card:hover {
    background: var(--hover-bg);
    transform: translateY(-4px);
}

.card h2 {
    font-size: 1.5rem;
    margin-top: 0;
    margin-bottom: 1.5rem;
    color: var(--text-color);
    font-weight: 600;
}

.transfer-grid {
    display: grid;
    grid-template-columns: 380px 1fr;
    gap: 2rem;
    align-items: start;
}

.transfer-sidebar {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.transfer-main {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.status-card {
    text-align: center;
}

.status-bar {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 12px;
    margin-bottom: 1rem;
}

.status-text {
    font-size: 1rem;
    color: var(--text-muted);
    font-weight: 500;
}

.peers-card h3 {
    font-size: 1rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 1rem;
}

.peers-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.peer-item {
    background: var(--bg-dark);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.peer-item::before {
    content: '';
    width: 8px;
    height: 8px;
    background-color: var(--success);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--success);
}

.chat-card {
    display: flex;
    flex-direction: column;
    height: 550px;
}

.chat-card h3 {
    font-size: 1rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

#chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 10px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 1rem;
}

.chat-msg {
    font-size: 0.9rem;
    padding: 10px 16px;
    border-radius: 1.2rem;
    max-width: 80%;
    line-height: 1.4;
    animation: messageAppear 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
    position: relative;
}

.chat-msg.sent {
    align-self: flex-end;
    background: var(--accent-color);
    color: #0f172a;
    border-bottom-right-radius: 4px;
    animation-name: messageAppearSent;
}

.chat-msg.received {
    align-self: flex-start;
    background: var(--bg-dark);
    color: var(--text-color);
    border-bottom-left-radius: 4px;
    animation-name: messageAppearReceived;
}

.chat-msg code {
    background: rgba(0, 0, 0, 0.2);
    padding: 2px 4px;
    border-radius: 4px;
    font-family: monospace;
    font-size: 0.85rem;
}

.chat-msg.system {
    align-self: center;
    background: transparent;
    color: var(--text-muted);
    font-size: 0.75rem;
    text-align: center;
    max-width: 100%;
    animation: fadeIn 0.5s ease;
    font-style: italic;
}

.chat-msg .sender {
    font-size: 0.7rem;
    font-weight: 700;
    opacity: 0.8;
    display: block;
    margin-bottom: 4px;
    text-transform: uppercase;
}

.chat-msg .timestamp {
    font-size: 0.65rem;
    opacity: 0.6;
    display: block;
    text-align: right;
    margin-top: 4px;
}

@keyframes messageAppearSent {
    from { opacity: 0; transform: translateX(20px) scale(0.8); }
    to { opacity: 1; transform: translateX(0) scale(1); }
}

@keyframes messageAppearReceived {
    from { opacity: 0; transform: translateX(-20px) scale(0.8); }
    to { opacity: 1; transform: translateX(0) scale(1); }
}

@keyframes messageAppear {
    from { opacity: 0; transform: scale(0.8); }
    to { opacity: 1; transform: scale(1); }
}

/* Typing Indicator */
.typing-indicator {
    align-self: flex-start;
    background: var(--bg-dark);
    padding: 8px 16px;
    border-radius: 1.2rem;
    border-bottom-left-radius: 4px;
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1rem;
    font-size: 0.8rem;
    color: var(--text-muted);
}

.typing-text {
    font-style: italic;
}

.typing-dots {
    display: flex;
    gap: 4px;
}

.typing-dot {
    width: 4px;
    height: 4px;
    background: var(--text-muted);
    border-radius: 50%;
    animation: typingBounce 1.4s infinite ease-in-out;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
    0%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-4px); }
}


.chat-msg.sent {
    align-self: flex-end;
    background: linear-gradient(135deg, var(--accent-color), #6366f1);
    color: #0f172a;
    border-bottom-right-radius: 4px;
}

.chat-msg.received {
    align-self: flex-start;
    background: var(--bg-dark);
    color: var(--text-color);
    border-bottom-left-radius: 4px;
}

.chat-msg .sender {
    font-size: 0.7rem;
    font-weight: 700;
    opacity: 0.8;
    display: block;
    margin-bottom: 4px;
    text-transform: uppercase;
}

.chat-controls {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: auto;
}

.toolbar-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 0 8px;
    overflow-x: auto;
}

.markup-toolbar {
    display: flex;
    gap: 6px;
    flex-shrink: 0;
}

.markup-btn {
    background: var(--bg-dark);
    color: var(--text-color);
    border: 1px solid var(--card-border);
    padding: 6px 10px;
    font-size: 0.8rem;
    border-radius: 8px;
    cursor: pointer;
    box-shadow: none;
    width: auto;
    transition: all 0.2s;
}

.markup-btn:hover {
    background: var(--hover-bg);
    transform: none;
    box-shadow: none;
}

.suggestions-toolbar {
    display: flex;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 4px;
    scrollbar-width: none; /* Firefox */
}

.suggestions-toolbar::-webkit-scrollbar {
    display: none; /* Chrome/Safari */
}

.suggestion-btn {
    background: var(--bg-dark);
    color: var(--text-muted);
    border: 1px solid var(--card-border);
    padding: 4px 12px;
    font-size: 0.75rem;
    white-space: nowrap;
    border-radius: 20px;
    cursor: pointer;
    box-shadow: none;
    transition: all 0.2s;
}

.suggestion-btn:hover {
    background: var(--hover-bg);
    color: var(--text-color);
    transform: none;
    box-shadow: none;
}

.chat-input-group {
    display: flex;
    gap: 10px;
    background: var(--bg-dark);
    padding: 8px;
    border-radius: 1rem;
}

.upload-card {
    padding: 0;
}

.drop-zone {
    border-radius: 1.5rem;
    padding: 6rem 2rem;
    cursor: pointer;
    background: var(--bg-dark);
    text-align: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.drop-zone:hover, .drop-zone.drag-over {
    background: var(--hover-bg);
    transform: scale(1.01);
    box-shadow: 0 0 30px var(--accent-glow);
}

.upload-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

#drop-zone-text {
    font-size: 1.2rem;
    color: var(--text-muted);
}

#drop-zone-text span {
    color: var(--accent-color);
    font-weight: 600;
}

.progress-card {
    padding: 2rem;
}

.file-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

#file-name {
    font-weight: 600;
    color: var(--text-color);
}

.progress-bar {
    background: var(--bg-dark);
    border-radius: 1rem;
    height: 14px;
    width: 100%;
    overflow: hidden;
}

#progress-fill {
    background: linear-gradient(90deg, var(--accent-color), #818cf8);
    height: 100%;
    box-shadow: 0 0 15px var(--accent-color);
}

#progress-text {
    margin-top: 0.75rem;
    font-weight: 700;
    color: var(--accent-color);
    text-align: right;
}

button {
    background-color: var(--accent-color);
    color: #0f172a;
    border: none;
    padding: 0.8rem 1.8rem;
    font-size: 1rem;
    font-weight: 700;
    border-radius: 0.8rem;
    cursor: pointer;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

button:hover {
    filter: brightness(1.1);
    transform: translateY(-1px);
    box-shadow: 0 10px 15px -3px var(--accent-glow);
}

input, select {
    background: var(--input-bg);
    color: var(--text-color);
    border: 1px solid var(--input-border);
    padding: 0.8rem;
    border-radius: 0.8rem;
    font-size: 1rem;
    outline: none;
}

input:focus, select:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

.setup-inputs {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    margin-bottom: 2rem;
}

.input-group {
    display: flex;
    flex-direction: column;
    text-align: left;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-weight: 500;
}

#settings-btn {
    position: fixed;
    top: 30px;
    right: 30px;
    font-size: 1.8rem;
    cursor: pointer;
    z-index: 1100;
    background: var(--card-bg);
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    backdrop-filter: blur(10px);
}

#settings-btn:hover {
    transform: rotate(45deg);
    background: var(--hover-bg);
}

#settings-modal {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1200;
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background: var(--bg-dark);
    width: 450px;
    max-height: 90vh;
    border-radius: 2rem;
    display: flex;
    flex-direction: column;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    overflow: hidden;
}

.modal-header {
    padding: 1.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    margin: 0;
    font-size: 1.5rem;
}

.close-x {
    background: none;
    color: var(--text-muted);
    font-size: 1.8rem;
    padding: 0;
    width: auto;
    height: auto;
    box-shadow: none;
}

.close-x:hover {
    color: var(--text-color);
    transform: none;
}

.settings-body {
    padding: 2rem;
    overflow-y: auto;
}

.settings-group {
    margin-bottom: 2.5rem;
}

.group-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 1.2rem;
}

.group-icon {
    font-size: 1.2rem;
}

.group-header h3 {
    font-size: 0.9rem;
    color: var(--accent-color);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin: 0;
}

.setting-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.setting-info {
    display: flex;
    flex-direction: column;
    text-align: left;
}

.setting-label {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-color);
}

.setting-desc {
    font-size: 0.8rem;
    color: var(--text-dim);
}

.settings-input {
    width: 150px;
}

.settings-select {
    width: 140px;
}

.modal-footer {
    padding: 1.5rem 2rem;
    text-align: right;
}

.btn-secondary {
    background: var(--bg-dark);
    color: var(--text-color);
}

.btn-secondary:hover {
    background: var(--hover-bg);
}

.btn-danger {
    background-color: var(--danger);
    color: white;
    width: 100%;
}

.color-picker {
    display: flex;
    gap: 12px;
}

.color-option {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 0 0 2px var(--bg-dark);
}

.color-option.active {
    transform: scale(1.2);
    box-shadow: 0 0 0 2px var(--text-color);
}

.switch {
    position: relative;
    display: inline-block;
    width: 48px;
    height: 24px;
}

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

.slider {
    position: absolute;
    cursor: pointer;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: var(--bg-dark);
    transition: .3s;
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: var(--text-color);
    transition: .3s;
    border-radius: 50%;
}

input:checked + .slider { background-color: var(--accent-color); }
input:checked + .slider:before { transform: translateX(24px); }

.hidden { display: none !important; }

#snackbar-container {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.snackbar {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    color: var(--text-color);
    padding: 14px 24px;
    border-radius: 1rem;
    border-left: 4px solid var(--accent-color);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    font-size: 0.9rem;
    animation: slideUp 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275), fadeOut 0.5s ease-in 4.5s forwards;
}

@keyframes slideUp { from { transform: translateY(100%); opacity: 0; } to { transform: translateY(0); opacity: 1; } }
@keyframes fadeOut { from { opacity: 1; } to { opacity: 0; } }

#loader {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.spinner {
    width: 60px;
    height: 60px;
    border: 4px solid rgba(56, 189, 248, 0.1);
    border-top: 4px solid var(--accent-color);
    border-radius: 50%;
    animation: spin 1s cubic-bezier(0.5, 0, 0.5, 1) infinite;
    margin-bottom: 1.5rem;
}

@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }

@media (max-width: 900px) {
    .transfer-grid { 
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .transfer-sidebar { 
        order: 2;
        width: 100%;
    }
    
    .transfer-main { 
        order: 1;
        width: 100%;
    }
}

@media (max-width: 600px) {
    .container {
        padding: 1rem 0.75rem;
    }
    
    .app-header {
        margin-bottom: 2.5rem;
    }

    h1 { 
        font-size: 2.2rem; 
        letter-spacing: -1px;
    }
    
    .setup-grid { 
        grid-template-columns: 1fr; 
        gap: 1rem;
    }
    
    .card { 
        padding: 1.25rem; 
        border-radius: 1.25rem;
    }

    .drop-zone {
        padding: 3rem 1rem;
    }

    .upload-icon {
        font-size: 3rem;
    }

    .chat-card {
        height: 400px;
    }

    .toolbar-row {
        flex-direction: column;
        align-items: stretch;
        gap: 12px;
    }

    .markup-toolbar {
        justify-content: center;
    }

    .suggestions-toolbar {
        justify-content: center;
    }

    .modal-content { 
        width: 95vw; 
        border-radius: 1.5rem;
        padding: 1rem;
    }
    
    .modal-header, .modal-footer {
        padding: 1rem;
    }

    .settings-body {
        padding: 1rem;
    }
}

/* Custom Scrollbars */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: transparent;
    border-radius: 10px;
    transition: background var(--transition-speed);
}

body:hover ::-webkit-scrollbar-thumb,
.modal-content:hover ::-webkit-scrollbar-thumb,
#chat-messages:hover ::-webkit-scrollbar-thumb {
    background: var(--text-dim);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-color) !important;
}

/* Firefox scrollbar */
* {
    scrollbar-width: thin;
    scrollbar-color: transparent transparent;
}

body:hover, .modal-content:hover, #chat-messages:hover {
    scrollbar-color: var(--text-dim) transparent;
}