body {
    font-family: "Helvetica Neue", Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: radial-gradient(circle at top left, rgba(0,161,214,0.18), transparent 28%),
                radial-gradient(circle at bottom right, rgba(0,130,188,0.16), transparent 30%),
                #eef5fb;
    color: #222;
}
header {
    background: linear-gradient(135deg, #0078b8, #00a1d6);
    color: white;
    padding: 28px 20px;
    text-align: center;
    box-shadow: 0 12px 30px rgba(0,0,0,0.12);
}
header h1 {
    margin: 0 0 8px;
    font-size: 2rem;
    letter-spacing: 0.02em;
}
.note-text {
    margin: 0;
    font-size: 0.95rem;
    color: #ebf6ff;
    line-height: 1.6;
}
.note-text a {
    color: #ffd05b;
    text-decoration: underline;
    font-weight: 700;
}
.container {
    max-width: 860px;
    margin: 24px auto 40px;
    padding: 30px;
    background-color: rgba(255,255,255,0.96);
    border-radius: 24px;
    border: 1px solid rgba(0,0,0,0.04);
    box-shadow: 0 24px 60px rgba(0,0,0,0.08);
}
.form-container {
    margin: 24px 0 12px;
}
form {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}
input[type="text"] {
    width: min(100%, 560px);
    padding: 14px 18px;
    font-size: 16px;
    border: 1px solid rgba(0,0,0,0.12);
    border-radius: 999px;
    outline: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
input[type="text"]:focus {
    border-color: #00a1d6;
    box-shadow: 0 0 0 4px rgba(0,161,214,0.14);
}
input[type="submit"] {
    background: linear-gradient(135deg, #0078b8, #00a1d6);
    color: white;
    border: none;
    padding: 14px 30px;
    font-size: 16px;
    border-radius: 999px;
    cursor: pointer;
    box-shadow: 0 12px 24px rgba(0,161,214,0.18);
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
input[type="submit"]:hover {
    transform: translateY(-1px);
    box-shadow: 0 18px 30px rgba(0,161,214,0.23);
    background: linear-gradient(135deg, #005f91, #008fcc);
}
.result {
    margin: 32px 0;
    padding: 26px 24px;
    background-color: #f8fbff;
    border-radius: 20px;
    text-align: center;
    border: 1px solid rgba(0,161,214,0.12);
}
.video-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-top: 18px;
}
.video-item {
    display: inline-flex;
    align-items: center;
    justify-content: center;
}
.error {
    color: #c62828;
    margin: 18px 0;
    text-align: center;
    font-weight: 600;
    background: rgba(255,230,230,0.9);
    border: 1px solid rgba(198,40,40,0.2);
    padding: 14px 18px;
    border-radius: 14px;
}
.download-btn {
    background: linear-gradient(135deg, #00a1d6, #0078b8);
    color: white;
    padding: 12px 22px;
    text-decoration: none;
    border-radius: 999px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin: 12px 8px;
    border: none;
    cursor: pointer;
    font-weight: 700;
    transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
    box-shadow: 0 14px 28px rgba(0,161,214,0.18);
}
.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 20px 30px rgba(0,161,214,0.28);
    filter: brightness(1.05);
}
.download-btn:active {
    transform: translateY(0);
}
.progress-card {
    margin-top: 24px;
    padding: 18px;
    background: rgba(255,255,255,0.95);
    border-radius: 18px;
    border: 1px solid rgba(0,0,0,0.05);
}
.progress-bar-track {
    width: 100%;
    height: 18px;
    background: #e8f3ff;
    border-radius: 999px;
    overflow: hidden;
    margin-top: 10px;
}
.progress-bar-fill {
    width: 0%;
    height: 100%;
    background: linear-gradient(90deg, #00a1d6, #0078b8);
    transition: width 0.3s ease;
}
footer {
    text-align: center;
    padding: 18px;
    background: transparent;
    color: #444;
    margin-top: 40px;
    font-size: 0.95rem;
}
@media (max-width: 720px) {
    .container {
        margin: 16px;
        padding: 20px;
    }
    input[type="text"] {
        width: 100%;
    }
    .download-btn {
        width: 100%;
        justify-content: center;
    }
    .video-list {
        flex-direction: column;
    }
}