:root {
    --bg-color: hsl(222, 47%, 11%); /* Deep navy */
    --panel-bg: rgba(23, 33, 54, 0.6);
    --panel-border: rgba(255, 255, 255, 0.1);
    --text-primary: #ffffff;
    --text-secondary: #94a3b8;
    --accent-gradient: linear-gradient(135deg, #06b6d4, #8b5cf6); /* cyan to violet */
    --accent-hover: linear-gradient(135deg, #0891b2, #7c3aed);
    --accent-color: #06b6d4;
    --danger: #ef4444;
    --success: #10b981;
    --glass-blur: blur(20px);
}

[data-theme="light"] {
    --bg-color: #f8fafc;
    --panel-bg: rgba(255, 255, 255, 0.8);
    --panel-border: rgba(0, 0, 0, 0.1);
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --accent-gradient: linear-gradient(135deg, #0891b2, #6d28d9);
    --accent-color: #0891b2;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.3s ease;
}

/* Glassmorphism */
.glass-card {
    background: var(--panel-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--panel-border);
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.actions {
    display: flex;
    gap: 1rem;
}

.icon-btn {
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.icon-btn:hover:not(:disabled) {
    background-color: rgba(255, 255, 255, 0.1);
}

.icon-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

main {
    flex: 1;
    padding: 0 2rem 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

.lang-switcher {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    box-shadow: 0 4px 6px var(--shadow-color);
    backdrop-filter: blur(10px);
}

.lang-box {
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--text-primary);
    min-width: 150px;
    text-align: center;
}

#swap-lang-btn {
    font-size: 1.5rem;
    padding: 0.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

#swap-lang-btn:hover {
    background-color: var(--border-color);
    transform: scale(1.1);
}

.panels-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    flex: 1;
    min-height: 500px;
}

@media (max-width: 768px) {
    .panels-container {
        grid-template-columns: 1fr;
    }
}

.panel {
    display: flex;
    flex-direction: column;
    animation: slideIn 0.5s ease backwards;
}

.panel:nth-child(2) {
    animation-delay: 0.1s;
}

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

.panel-header {
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--panel-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.tabs {
    display: flex;
    gap: 1rem;
}

.tab-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    padding: 0.5rem 0;
    position: relative;
    font-family: 'Inter', sans-serif;
}

.tab-btn.active {
    color: var(--accent-color);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1rem;
    left: 0;
    width: 100%;
    height: 3px;
    background: var(--accent-gradient);
    border-radius: 3px 3px 0 0;
}

.panel-title {
    font-size: 1rem;
    font-weight: 500;
    padding: 0.5rem 0;
}

.output-actions {
    display: flex;
    gap: 0.5rem;
}

.panel-body {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding: 1.5rem;
    position: relative;
}

.tab-content {
    display: none;
    flex: 1;
    flex-direction: column;
}

.tab-content.active {
    display: flex;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

textarea {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1.1rem;
    line-height: 1.6;
    resize: none;
    outline: none;
}

textarea::placeholder {
    color: var(--text-secondary);
}

#en-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 1rem;
}

.char-count {
    text-align: right;
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-top: 0.5rem;
}

.drop-zone {
    flex: 1;
    border: 2px dashed var(--text-secondary);
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    transition: all 0.3s;
    text-align: center;
}

.drop-zone.dragover {
    border-color: var(--accent-color);
    background: rgba(6, 182, 212, 0.1);
    box-shadow: 0 0 20px rgba(6, 182, 212, 0.2);
}

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

.sub-text, .file-limits {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.file-name {
    color: var(--accent-color);
    font-weight: 500;
    margin-top: 1rem;
    word-break: break-all;
}

.hidden {
    display: none !important;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--panel-border);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.btn {
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}

.btn.primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(6, 182, 212, 0.3);
}

.btn.primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(6, 182, 212, 0.4);
}

.btn.primary:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

.btn.secondary {
    background: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
}

.btn.secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

.translate-action {
    display: flex;
    justify-content: center;
}

.translate-btn {
    padding: 1rem 3rem;
    font-size: 1.1rem;
    border-radius: 30px;
    position: relative;
    overflow: hidden;
}

.translate-btn.loading {
    cursor: wait;
}

.translate-btn.loading::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 200%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    animation: pulse 1.5s infinite linear;
}

@keyframes pulse {
    from { transform: translateX(0); }
    to { transform: translateX(100%); }
}

footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Modal */
dialog {
    margin: auto;
    padding: 2rem;
    width: 90%;
    max-width: 400px;
    color: var(--text-primary);
    border: 1px solid var(--panel-border);
}

dialog::backdrop {
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
}

dialog[open] {
    animation: modalScale 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes modalScale {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

.form-group {
    margin: 1.5rem 0;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-with-icon {
    display: flex;
    align-items: center;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--panel-border);
    border-radius: 8px;
    padding-right: 0.5rem;
}

.input-with-icon input {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    padding: 0.75rem 1rem;
    outline: none;
    font-family: inherit;
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
}

.help-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.help-text a {
    color: var(--accent-color);
    text-decoration: none;
}

.help-text a:hover {
    text-decoration: underline;
}

/* Tooltip */
.tooltip {
    position: relative;
}

.tooltip::before {
    content: attr(data-tooltip);
    position: absolute;
    bottom: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(-5px);
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s;
    pointer-events: none;
    z-index: 100;
}

.tooltip:hover::before {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(-10px);
}

/* Loading Overlay */
.output-container {
    position: relative;
    flex: 1;
    display: flex;
}

.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--panel-bg);
    border-radius: 8px;
    overflow: hidden;
}

.shimmer {
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, 
        transparent 0%, 
        rgba(255, 255, 255, 0.05) 50%, 
        transparent 100%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* Toasts */
#toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    padding: 1rem 1.5rem;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    animation: toastSlide 0.3s ease forwards;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    max-width: 400px;
}

.toast-message {
    flex: 1;
}

.toast-close {
    background: transparent;
    border: none;
    color: white;
    font-size: 1rem;
    cursor: pointer;
    opacity: 0.7;
    transition: opacity 0.2s;
    padding: 0;
    margin-left: 0.5rem;
}

.toast-close:hover {
    opacity: 1;
}

.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }
.toast.info { background: var(--accent-color); }

.toast.fadeOut {
    animation: toastFadeOut 0.3s ease forwards;
}

@keyframes toastSlide {
    from { opacity: 0; transform: translateX(100%); }
    to { opacity: 1; transform: translateX(0); }
}

@keyframes toastFadeOut {
    from { opacity: 1; transform: translateX(0); }
    to { opacity: 0; transform: translateX(100%); }
}