:root {
    --bg-primary: #0b0f19;
    --bg-card: rgba(23, 31, 48, 0.75);
    --bg-card-hover: rgba(30, 41, 64, 0.85);
    --border-color: rgba(255, 255, 255, 0.08);
    --border-active: #6366f1;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-glow: rgba(99, 102, 241, 0.35);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --text-dim: #64748b;
    --accent-green: #10b981;
    --accent-red: #ef4444;
    --radius-lg: 20px;
    --radius-md: 12px;
    --radius-sm: 8px;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 24px;
    position: relative;
    overflow-x: hidden;
}

/* Background gradient blobs */
.background-decorations {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.circle {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.25;
}

.circle-1 {
    width: 450px;
    height: 450px;
    background: #6366f1;
    top: -100px;
    left: -100px;
}

.circle-2 {
    width: 500px;
    height: 500px;
    background: #06b6d4;
    bottom: -150px;
    right: -100px;
}

.container {
    width: 100%;
    max-width: 680px;
    position: relative;
    z-index: 1;
}

/* Header */
.app-header {
    text-align: center;
    margin-bottom: 28px;
}

.badge-tag {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(99, 102, 241, 0.12);
    border: 1px solid rgba(99, 102, 241, 0.25);
    color: #a5b4fc;
    font-size: 0.8rem;
    font-weight: 600;
    padding: 5px 14px;
    border-radius: 100px;
    margin-bottom: 14px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.pulse-dot {
    width: 8px;
    height: 8px;
    background: var(--accent-green);
    border-radius: 50%;
    box-shadow: 0 0 10px var(--accent-green);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(0.95); opacity: 0.8; }
    50% { transform: scale(1.2); opacity: 1; }
    100% { transform: scale(0.95); opacity: 0.8; }
}

.app-header h1 {
    font-size: 2.2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
}

.app-header h1 span {
    background: linear-gradient(135deg, #818cf8 0%, #38bdf8 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-muted);
    font-size: 0.95rem;
    max-width: 480px;
    margin: 0 auto;
    line-height: 1.5;
}

/* Main Card */
.card {
    background: var(--bg-card);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 30px;
    box-shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.5);
    display: flex;
    flex-direction: column;
    gap: 24px;
}

/* Dropzone */
.dropzone {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-md);
    padding: 36px 20px;
    text-align: center;
    background: rgba(15, 23, 42, 0.4);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.dropzone:hover, .dropzone.dragover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.06);
    box-shadow: 0 0 25px rgba(99, 102, 241, 0.15);
}

.file-input {
    position: absolute;
    width: 0;
    height: 0;
    opacity: 0;
}

.upload-icon {
    color: var(--primary);
    margin-bottom: 12px;
    display: flex;
    justify-content: center;
}

.dropzone h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.dropzone p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.btn-link {
    background: none;
    border: none;
    color: #818cf8;
    font-weight: 600;
    cursor: pointer;
    text-decoration: underline;
}

.btn-link:hover {
    color: #a5b4fc;
}

.file-hint {
    display: inline-block;
    margin-top: 10px;
    font-size: 0.75rem;
    color: var(--text-dim);
}

/* File List */
.file-list-container {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
}

.file-list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.file-list-header h4 {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.btn-clear {
    background: none;
    border: none;
    color: var(--accent-red);
    font-size: 0.8rem;
    cursor: pointer;
    font-weight: 500;
}

.btn-clear:hover {
    text-decoration: underline;
}

.file-list {
    max-height: 180px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding-right: 4px;
}

.file-list::-webkit-scrollbar {
    width: 6px;
}

.file-list::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(30, 41, 59, 0.5);
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
}

.file-info {
    display: flex;
    align-items: center;
    gap: 10px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-name {
    font-weight: 500;
    color: var(--text-main);
}

.file-size {
    color: var(--text-dim);
    font-size: 0.75rem;
}

.btn-remove-file {
    background: none;
    border: none;
    color: var(--text-dim);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    display: flex;
    align-items: center;
    transition: var(--transition);
}

.btn-remove-file:hover {
    color: var(--accent-red);
    background: rgba(239, 68, 68, 0.1);
}

/* Bitrate Selector */
.section-label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 10px;
}

.bitrate-selector {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

.bitrate-pill {
    cursor: pointer;
}

.bitrate-pill input {
    display: none;
}

.pill-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 10px 8px;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: var(--transition);
    text-align: center;
}

.pill-content strong {
    font-size: 0.9rem;
    color: var(--text-main);
}

.pill-content small {
    font-size: 0.7rem;
    color: var(--text-dim);
    margin-top: 2px;
}

.bitrate-pill input:checked + .pill-content {
    background: rgba(99, 102, 241, 0.15);
    border-color: var(--primary);
    box-shadow: 0 0 15px rgba(99, 102, 241, 0.2);
}

.bitrate-pill input:checked + .pill-content strong {
    color: #818cf8;
}

/* Progress */
.progress-box {
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 14px;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    margin-bottom: 8px;
    font-weight: 500;
}

.progress-bar-track {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 100px;
    overflow: hidden;
}

.progress-bar-fill {
    width: 0%;
    height: 100%;
    background: linear-gradient(90deg, #6366f1, #38bdf8);
    border-radius: 100px;
    transition: width 0.3s ease;
}

/* Convert Button */
.btn-convert {
    width: 100%;
    background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: 14px 20px;
    font-size: 1rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    cursor: pointer;
    box-shadow: 0 10px 25px var(--primary-glow);
    transition: var(--transition);
}

.btn-convert:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 14px 30px rgba(99, 102, 241, 0.5);
}

.btn-convert:active:not(:disabled) {
    transform: translateY(0);
}

.btn-convert:disabled {
    opacity: 0.45;
    cursor: not-allowed;
    box-shadow: none;
}

/* Alerts */
.alert-box {
    border-radius: var(--radius-md);
    padding: 14px 16px;
    font-size: 0.88rem;
    line-height: 1.4;
}

.alert-success {
    background: rgba(16, 185, 129, 0.12);
    border: 1px solid rgba(16, 185, 129, 0.3);
    color: #6ee7b7;
}

.alert-error {
    background: rgba(239, 68, 68, 0.12);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #fca5a5;
}

/* Footer features */
.app-footer {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-top: 24px;
}

.feature-item {
    background: rgba(15, 23, 42, 0.4);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 14px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
}

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

.feature-item strong {
    font-size: 0.85rem;
    color: var(--text-main);
    display: block;
    margin-bottom: 2px;
}

.feature-item p {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.35;
}

/* Responsive */
@media (max-width: 600px) {
    .bitrate-selector {
        grid-template-columns: repeat(2, 1fr);
    }
    .app-footer {
        grid-template-columns: 1fr;
    }
    .card {
        padding: 20px;
    }
}