/* Clean Glassmorphism Design System */
:root {
    /* Color Palette */
    --bg: #0b1020;
    --surface: rgba(17,24,39,0.6);
    --card: rgba(11,18,32,0.45);
    --muted: #94a3b8;
    --text: #e5e7eb;
    --primary: #6366f1;
    --primary-600: #5458e8;
    --primary-700: #474bdc;
    --accent: #22d3ee;
    --success: #22c55e;
    --danger: #ef4444;
    --warning: #f59e0b;
    --ring: rgba(99,102,241,0.35);
    
    /* Button System */
    --btn-radius: 10px;
    --btn-padding-y: 12px;
    --btn-padding-x: 24px;
    --btn-font: 500 .95rem/1.1 var(--font-sans, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, Arial, Noto Sans, "Apple Color Emoji", "Segoe UI Emoji");
    
    /* Button Colors */
    --primary-600: #2b7cff;
    --primary-500: #4c8eff;
    --primary-400: #6aa0ff;
    --secondary-600: #ff8a3d;
    --secondary-500: #ffa056;
    --secondary-400: #ffb476;
    --neutral-700: #94a3b8;
    --neutral-600: #a8b1c3;
    --neutral-500: #c5ccda;
    --danger-600: #ff5b6e;
    --danger-500: #ff7685;
    --danger-400: #ff919c;
    
    /* Surface & Elevation */
    --surface: #0b1021;
    --elev-1: rgba(255,255,255,0.06);
    --elev-2: rgba(255,255,255,0.1);
    --focus: #7dd3fc;
}

* {
    box-sizing: border-box;
}

html, body {
    height: 100%;
}

body {
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
    margin: 0;
    padding: 0;
    color: var(--text);
    background: var(--bg);
    /* Enhanced smooth scrolling */
    scroll-behavior: smooth;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: smooth;
    /* Optimize for performance */
    will-change: scroll-position;
    transform: translateZ(0);
    backface-visibility: hidden;
}

/* Header */
header {
    position: sticky;
    top: 0;
    z-index: 60;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 14px 18px;
    border-bottom: 1px solid var(--elev-1);
    background: linear-gradient(135deg, rgba(15,23,42,0.45), rgba(2,6,23,0.35));
    backdrop-filter: saturate(130%) blur(10px);
    -webkit-backdrop-filter: saturate(130%) blur(10px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.18);
}

header h1 {
    margin: 0;
    font-weight: 700;
    letter-spacing: .3px;
    text-shadow: 0 2px 14px rgba(99,102,241,0.35);
    font-size: 1.6rem;
    color: var(--text);
}

/* Main container */
main {
    padding: 22px;
    max-width: 1200px;
    margin: 18px auto;
    background: linear-gradient(180deg, rgba(255,255,255,0.03), rgba(255,255,255,0));
    border: 1px solid var(--elev-1);
    border-radius: 16px;
    box-shadow: 0 12px 32px rgba(0,0,0,0.22);
    min-height: calc(100vh - 140px);
    /* Enhanced scroll performance */
    transform: translateZ(0);
    will-change: scroll-position;
    -webkit-overflow-scrolling: touch;
}

/* Section cards */
section {
    margin-bottom: 24px;
    padding: 18px;
    border: 1px solid var(--elev-1);
    border-radius: 16px;
    background: linear-gradient(180deg, rgba(17,24,39,0.55), rgba(2,6,23,0.5));
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    box-shadow: 0 10px 28px rgba(0,0,0,0.22);
}

h2 {
    color: #e2e8f0;
    border-bottom: 1px dashed rgba(148,163,184,0.25);
    padding-bottom: 10px;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.08rem;
}

/* Drag area */
.drag-drop-area {
    border: 2px dashed rgba(148,163,184,0.35);
    padding: 34px;
    text-align: center;
    cursor: pointer;
    margin-bottom: 16px;
    border-radius: 14px;
    transition: all .25s ease;
    background: rgba(2,6,23,0.32);
}

.drag-drop-area:hover {
    background: rgba(99,102,241,0.08);
    border-color: rgba(99,102,241,0.55);
    box-shadow: 0 10px 22px rgba(99,102,241,0.15);
}

input[type="file"] {
    display: none;
}

label {
    font-weight: 600;
    margin-bottom: 6px;
    display: inline-block;
    color: #cbd5e1;
}

select, input[type="number"], input[type="text"], textarea, input[type="password"] {
    width: 100%;
    padding: 11px 12px;
    margin-bottom: 12px;
    border: 1px solid rgba(148,163,184,0.25);
    border-radius: 10px;
    font-size: .98rem;
    background: rgba(15,23,42,0.6);
    color: var(--text);
    outline: none;
    transition: border .2s, box-shadow .2s;
}

select:focus, input[type="number"]:focus, input[type="text"]:focus, textarea:focus, input[type="password"]:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px var(--ring);
}

textarea {
    resize: vertical;
    min-height: 120px;
}

.api-settings {
    margin-bottom: 16px;
}

.api-settings label {
    display: block;
    margin-bottom: 6px;
    font-weight: 700;
}

/* Layout helpers */
.btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.split-card {
    border: 1px solid rgba(148,163,184,0.25);
    border-radius: 12px;
    padding: 12px;
    background: rgba(2,6,23,0.32);
    backdrop-filter: blur(6px);
}

.toggle-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.checkbox-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 6px;
}

.helper {
    display: block;
    color: #94a3b8;
    margin: 6px 0 0;
}

.inline-hint .hint {
    color: #94a3b8;
    font-size: .9rem;
}

/* Button System */
button {
    border-radius: var(--btn-radius);
    padding: var(--btn-padding-y) var(--btn-padding-x);
    font: var(--btn-font);
    border: 1px solid transparent;
    background: linear-gradient(180deg, rgba(255,255,255,0.1), rgba(255,255,255,0.02));
    color: #e7eefc;
    letter-spacing: .2px;
    transition: transform .08s ease, box-shadow .15s ease, filter .15s ease, background .2s ease, border-color .2s ease;
    box-shadow: 0 6px 14px rgba(0,0,0,0.25), inset 0 1px 0 rgba(255,255,255,0.06);
}

button:hover:not(:disabled) {
    transform: translateY(-1px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.35), inset 0 1px 0 rgba(255,255,255,0.08);
}

button:active:not(:disabled) {
    transform: translateY(0);
    box-shadow: 0 6px 12px rgba(0,0,0,0.28), inset 0 2px 6px rgba(0,0,0,0.35);
}

button:disabled {
    opacity: .55;
    cursor: not-allowed;
    filter: grayscale(.15);
}

button:focus-visible {
    outline: 2px solid var(--focus);
    outline-offset: 2px;
}

/* Primary: Start & Resume */
button.start, button.resume {
    background: linear-gradient(180deg, #3b82f6, #2563eb);
    border-color: rgba(59,130,246,0.4);
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
    font-weight: 600;
}

button.start:hover:not(:disabled), button.resume:hover:not(:disabled) {
    background: linear-gradient(180deg, #60a5fa, #3b82f6);
    filter: brightness(1.1);
    transform: translateY(-1px);
}

button.start:active:not(:disabled), button.resume:active:not(:disabled) {
    background: linear-gradient(180deg, #3b82f6, #2563eb);
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
}

/* Secondary: Pause */
button.pause {
    background: linear-gradient(180deg, #ff8a3d, #ff6b1a);
    border-color: rgba(255,138,61,0.4);
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
    font-weight: 600;
}

button.pause:hover:not(:disabled) {
    background: linear-gradient(180deg, #ff9d5c, #ff8a3d);
    filter: brightness(1.1);
    transform: translateY(-1px);
}

button.pause:active:not(:disabled) {
    background: linear-gradient(180deg, #ff8a3d, #ff6b1a);
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
}

/* Destructive: Cancel */
button.cancel {
    background: linear-gradient(180deg, #ef4444, #dc2626);
    border-color: rgba(239,68,68,0.4);
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
    font-weight: 600;
}

button.cancel:hover:not(:disabled) {
    background: linear-gradient(180deg, #f87171, #ef4444);
    filter: brightness(1.1);
    transform: translateY(-1px);
}

button.cancel:active:not(:disabled) {
    background: linear-gradient(180deg, #ef4444, #dc2626);
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
}

/* Neutral: Clear All */
button.clear-all {
    background: linear-gradient(180deg, #64748b, #475569);
    border-color: rgba(100,116,139,0.4);
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
    font-weight: 600;
}

button.clear-all:hover:not(:disabled) {
    background: linear-gradient(180deg, #94a3b8, #64748b);
    filter: brightness(1.1);
    transform: translateY(-1px);
}

button.clear-all:active:not(:disabled) {
    background: linear-gradient(180deg, #64748b, #475569);
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
}

/* Download: consistent */
button.download-txt, button.download-zip {
    background: linear-gradient(180deg, rgba(255,255,255,0.12), rgba(255,255,255,0.04));
    border-color: rgba(255,255,255,0.16);
    color: #e7eefc;
}

button.download-txt:hover:not(:disabled), button.download-zip:hover:not(:disabled) {
    filter: brightness(1.05);
}

button.download-txt:active:not(:disabled), button.download-zip:active:not(:disabled) {
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
}

/* Copy to Clipboard */
button.copy-clipboard {
    background: linear-gradient(180deg, rgba(255,255,255,0.12), rgba(255,255,255,0.04));
    border-color: rgba(255,255,255,0.16);
    color: #e7eefc;
}

button.copy-clipboard:hover:not(:disabled) {
    filter: brightness(1.05);
}

button.copy-clipboard:active:not(:disabled) {
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
}

/* Progress & Logs */
.progress-bar-container {
    background: rgba(2,6,23,0.5);
    border: 1px solid rgba(148,163,184,0.25);
    border-radius: 10px;
    margin-top: 14px;
    height: 22px;
    overflow: hidden;
    position: relative;
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: repeating-linear-gradient(45deg, var(--success), var(--success) 10px, #28a745 10px, #28a745 20px);
    border-radius: 10px;
    text-align: center;
    color: white;
    line-height: 22px;
    transition: width .45s ease;
}

#progress-text {
    position: absolute;
    width: 100%;
    text-align: center;
    line-height: 22px;
    top: 0;
    left: 0;
    color: #cbd5e1;
    font-size: .88rem;
}

#log-panel {
    background: rgba(15,23,42,0.5);
    border: 1px solid rgba(148,163,184,0.25);
    border-radius: 12px;
    padding: 12px;
    margin-top: 14px;
    backdrop-filter: blur(6px);
}

#log-panel h3 {
    margin-top: 0;
    color: #e2e8f0;
}

#log-content {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 220px;
    overflow-y: auto;
    background: rgba(2,6,23,0.5);
    padding: 12px;
    border-radius: 10px;
    color: #cbd5e1;
    /* Enhanced scroll performance */
    transform: translateZ(0);
    will-change: scroll-position;
    -webkit-overflow-scrolling: touch;
}

/* Split views */
.split-view {
    display: flex;
    gap: 18px;
    margin-top: 16px;
    flex-wrap: wrap;
}

.original-view, .translated-view {
    flex: 1;
    min-width: 300px;
    border: 1px solid rgba(148,163,184,0.25);
    border-radius: 14px;
    padding: 14px;
    background: linear-gradient(180deg, rgba(15,23,42,0.55), rgba(2,6,23,0.5));
    box-shadow: 0 10px 22px rgba(0,0,0,0.2);
    backdrop-filter: blur(6px);
}

.split-view h3 {
    color: #e2e8f0;
    margin-top: 0;
    border-bottom: 1px dashed rgba(148,163,184,0.25);
    padding-bottom: 8px;
    margin-bottom: 10px;
}

.split-view pre {
    white-space: pre-wrap;
    word-break: break-word;
    max-height: 220px;
    overflow-y: auto;
    background: rgba(2,6,23,0.5);
    padding: 12px;
    border-radius: 10px;
    color: #e5e7eb;
    /* Enhanced scroll performance */
    transform: translateZ(0);
    will-change: scroll-position;
    -webkit-overflow-scrolling: touch;
}

.download-options, .statistics {
    margin-top: 16px;
    padding-top: 12px;
    border-top: 1px dashed rgba(148,163,184,0.25);
}

.statistics p {
    margin: 6px 0;
    color: #cbd5e1;
}

/* Footer */
footer {
    position: sticky;
    bottom: 0;
    z-index: 40;
    padding: 14px 18px;
    margin-top: 22px;
    color: #94a3b8;
    font-size: .92rem;
    border-top: 1px solid var(--elev-1);
    border-top-left-radius: 16px;
    border-top-right-radius: 16px;
    background: linear-gradient(135deg, rgba(15,23,42,0.45), rgba(2,6,23,0.35));
    backdrop-filter: saturate(130%) blur(10px);
    -webkit-backdrop-filter: saturate(130%) blur(10px);
    box-shadow: 0 -8px 24px rgba(0,0,0,0.18);
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
}

.github-link {
    display: flex;
    align-items: center;
    justify-content: center;
    color: #94a3b8;
    text-decoration: none;
    padding: 6px;
    border-radius: 6px;
    transition: all 0.2s ease;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
}

.github-link:hover {
    color: #e5e7eb;
    background: rgba(255,255,255,0.1);
    border-color: rgba(255,255,255,0.2);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.github-link svg {
    transition: transform 0.2s ease;
}

.github-link:hover svg {
    transform: scale(1.1);
}

/* Error message */
.error-message {
    background: linear-gradient(135deg, rgba(239,68,68,0.15), rgba(239,68,68,0.08));
    border: 1px solid rgba(239,68,68,0.35);
    color: #fecaca;
    padding: 12px 14px;
    border-radius: 10px;
    margin-top: 12px;
}

/* Mobile responsive */
@media (max-width: 768px) {
    main {
        padding: 14px;
    }
    
    button {
        width: 100%;
        margin-right: 0;
        margin-bottom: 10px;
        padding: 10px 18px;
        font-size: .92rem;
    }
    
    .split-view {
        flex-direction: column;
    }
    
    .grid-2 {
        grid-template-columns: 1fr;
    }
    
    header h1 {
        font-size: 1.2rem;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 8px;
    }
    
    .github-link {
        padding: 8px;
    }
}

/* Progress animation */
@keyframes progressPulse {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}