:root {
    /* Color System */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --success-gradient: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);

    /* Glassmorphism Colors */
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: rgba(0, 0, 0, 0.1);

    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-tertiary: rgba(255, 255, 255, 0.5);

    /* Background */
    --bg-dark: #0a0a0f;
    --bg-card: rgba(20, 20, 30, 0.6);

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    /* Animations */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
}

.background-gradient {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(circle at 20% 20%, rgba(102, 126, 234, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(245, 87, 108, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(67, 233, 123, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

.container {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
    z-index: 1;
}

/* Header Styles */
.header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    animation: fadeInDown 0.6s ease;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 2rem;
    font-weight: 800;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 400;
}

.mode-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.75rem;
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.mode-badge.api-mode {
    background: rgba(245, 158, 11, 0.1);
    border-color: rgba(245, 158, 11, 0.3);
    color: #fbbf24;
}

.mode-badge.local-mode {
    background: rgba(67, 233, 123, 0.1);
    border-color: rgba(67, 233, 123, 0.3);
    color: #43e97b;
}

.mode-badge svg {
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.5;
    }
}

/* Glass Card */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: 0 8px 32px var(--glass-shadow);
    transition: all var(--transition-normal);
}

.glass-card:hover {
    border-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 12px 48px rgba(0, 0, 0, 0.15);
}

/* Disclaimer */
.disclaimer {
    display: flex;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-radius: var(--radius-md);
    color: #fbbf24;
    font-size: 0.9rem;
    margin-bottom: var(--spacing-lg);
    animation: fadeIn 0.6s ease 0.2s both;
}

.disclaimer svg {
    flex-shrink: 0;
    margin-top: 2px;
}

/* Input Section */
.input-section {
    animation: fadeIn 0.6s ease 0.3s both;
}

.input-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.input-wrapper {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
}

#video-url {
    flex: 1;
    padding: 1rem 1.25rem;
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
    transition: all var(--transition-normal);
}

#video-url:focus {
    outline: none;
    border-color: #667eea;
    background: rgba(255, 255, 255, 0.08);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

#video-url::placeholder {
    color: var(--text-tertiary);
}

.input-hint {
    color: var(--text-tertiary);
    font-size: 0.875rem;
    margin-top: var(--spacing-xs);
}

/* Buttons */
.btn-primary {
    position: relative;
    padding: 1rem 2rem;
    background: var(--primary-gradient);
    border: none;
    border-radius: var(--radius-md);
    color: white;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-normal);
    overflow: hidden;
    white-space: nowrap;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(102, 126, 234, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-primary.loading {
    pointer-events: none;
}

.btn-primary.loading .btn-text {
    opacity: 0;
}

.btn-primary.loading .btn-loader {
    opacity: 1;
}

.btn-loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    opacity: 0;
    animation: spin 0.6s linear infinite;
}

/* Video Info */
.video-info {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    animation: fadeInUp 0.4s ease;
}

.video-thumbnail-wrapper {
    position: relative;
    flex-shrink: 0;
    width: 180px;
    height: 101px;
    border-radius: var(--radius-md);
    overflow: hidden;
}

#video-thumbnail {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.video-duration {
    position: absolute;
    bottom: 6px;
    right: 6px;
    padding: 4px 8px;
    background: rgba(0, 0, 0, 0.8);
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
}

.video-details {
    flex: 1;
    min-width: 0;
}

#video-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-meta {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.separator {
    margin: 0 var(--spacing-xs);
}

/* Formats Section */
.formats-section {
    margin-top: var(--spacing-lg);
    animation: fadeInUp 0.4s ease 0.1s both;
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.formats-list {
    display: grid;
    gap: var(--spacing-sm);
}

.format-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-md);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    animation: fadeInUp 0.3s ease backwards;
}

.format-item:hover {
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateX(4px);
    background: rgba(255, 255, 255, 0.08);
}

.format-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.quality-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 80px;
    padding: 0.5rem 1rem;
    background: var(--accent-gradient);
    border-radius: var(--radius-sm);
    font-weight: 700;
    font-size: 1rem;
}

.format-details {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.format-type {
    font-weight: 600;
    color: var(--text-primary);
}

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

.btn-download {
    padding: 0.75rem 1.5rem;
    background: var(--success-gradient);
    border: none;
    border-radius: var(--radius-sm);
    color: white;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.btn-download:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(67, 233, 123, 0.4);
}

.btn-download:active {
    transform: translateY(0);
}

.btn-download svg {
    width: 18px;
    height: 18px;
}

/* Error Message */
.error-message {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: var(--radius-md);
    color: #f87171;
    margin-top: var(--spacing-lg);
    animation: shake 0.4s ease;
}

.error-message svg {
    flex-shrink: 0;
}

/* Footer */
.footer {
    text-align: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

.heart {
    color: #f87171;
    animation: heartbeat 1.5s ease infinite;
}

.footer-note {
    margin-top: var(--spacing-xs);
    font-size: 0.85rem;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes spin {
    to {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-10px);
    }

    75% {
        transform: translateX(10px);
    }
}

@keyframes heartbeat {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    .logo {
        font-size: 1.5rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .input-wrapper {
        flex-direction: column;
    }

    .btn-primary {
        width: 100%;
    }

    .video-info {
        flex-direction: column;
    }

    .video-thumbnail-wrapper {
        width: 100%;
        height: auto;
        aspect-ratio: 16 / 9;
    }

    .format-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }

    .btn-download {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .format-info {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-xs);
    }
}