:root {
    --primary: #667eea;
    --primary-dark: #764ba2;
    --text: #2d3748;
    --border: #e2e8f0;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #f0f4ff, #d9e2ff);
    color: var(--text);
    min-height: 100vh;
    padding: 20px 0;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 20px 60px rgba(0,0,0,0.15);
}

header {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    text-align: center;
    padding: 50px 20px;
}

h1 {
    font-size: 2.8rem;
    font-weight: 800;
    margin-bottom: 12px;
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
}

.badges {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 25px;
    flex-wrap: wrap;
}

.badge {
    background: rgba(255,255,255,0.2);
    padding: 8px 16px;
    border-radius: 50px;
    font-size: 0.9rem;
    backdrop-filter: blur(10px);
}

.main {
    padding: 50px 40px;
}

.input-group {
    position: relative;
    margin-bottom: 30px;
}

#videoUrl {
    width: 100%;
    padding: 18px 20px;
    font-size: 1.1rem;
    border: 2px solid var(--border);
    border-radius: 14px;
    transition: all 0.3s;
}

#videoUrl:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.15);
}

.btn {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    padding: 18px 40px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 14px;
    cursor: pointer;
    width: 100%;
    transition: all 0.3s;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 30px rgba(102, 126, 234, 0.4);
}

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

.loading {
    text-align: center;
    padding: 40px;
    display: none;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid #f0f0f0;
    border-top: 5px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.result {
    margin-top: 40px;
    display: none;
}

.video-info {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    padding: 20px;
    border-radius: 14px;
    margin-bottom: 30px;
    text-align: center;
}

.video-info h2 {
    font-size: 1.6rem;
    margin-bottom: 8px;
}

.card {
    background: #f8f9ff;
    border-radius: 16px;
    padding: 25px;
    margin-bottom: 20px;
    border-left: 5px solid var(--primary);
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.summary-section {
    font-size: 1.6rem;
    font-weight: 800;
    color: #764ba2;
    margin-top: 30px;
    margin-bottom: 15px;
    padding-bottom: 5px;
}

.summary-content {
    font-size: 1.05rem;
    line-height: 1.8;
    margin-bottom: 20px;
}

footer {
    text-align: center;
    padding: 40px;
    background: #1a202c;
    color: #a0aec0;
    font-size: 0.9rem;
}

footer a {
    color: #667eea;
    text-decoration: none;
}
/* Mobile & small screen optimizations */
@media (max-width: 768px) {
    body {
        padding: 15px 0;
    }

    .container {
        margin: 0 10px;
        border-radius: 16px;
        box-shadow: 0 10px 40px rgba(0,0,0,0.1);
    }

    header {
        padding: 40px 15px;
    }

    h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
        padding: 0 5px;
    }

    .badges {
        gap: 10px;
    }

    .badge {
        padding: 6px 12px;
        font-size: 0.8rem;
    }

    .main {
        padding: 30px 20px;
    }

    #videoUrl {
        padding: 14px 16px;
        font-size: 1rem;
    }

    .btn {
        padding: 14px 20px;
        font-size: 1rem;
    }

    .spinner {
        width: 40px;
        height: 40px;
        border-width: 4px;
    }

    .summary-section {
        font-size: 1.3rem;
        margin-top: 20px;
        margin-bottom: 10px;
    }

    .summary-content {
        font-size: 0.95rem;
        line-height: 1.6;
    }

    footer {
        padding: 30px 15px;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.6rem;
    }

    .subtitle {
        font-size: 0.9rem;
    }

    .btn {
        padding: 12px 16px;
        font-size: 0.95rem;
    }

    .summary-section {
        font-size: 1.1rem;
    }

    .summary-content {
        font-size: 0.9rem;
    }
}