body {
    margin: 0;
    padding: 50px;
    background: #000;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    overflow: hidden;
    position: relative;
    user-select: none
}

.login-screen {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, .9);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    color: #fff
}

.login-button {
    background: #1db954;
    color: #fff;
    border: none;
    padding: 15px 30px;
    border-radius: 25px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: .3s;
    margin-top: 20px
}

.login-button:hover {
    background: #1ed760
}

.track-info {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #fff;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    pointer-events: none;
    max-width: 90vw;
    max-height: 85vh;
}

.track-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    grid-template-rows: repeat(3, 1fr);
    gap: 25px;
}

.guide-text {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.7);
    text-align: center;
    animation: blink 2s ease-in-out infinite;
    margin-bottom: 5px;
}

@keyframes blink {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 1; }
}

.track-info>* {
    pointer-events: auto;
}

.track-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    transition: all 0.3s ease;
    opacity: 0;
    animation: slideIn 0.5s ease forwards;
}

/* 첫 번째 줄 - 왼쪽에서 오른쪽으로 */
.track-item:nth-child(1) { animation-delay: 0s; }
.track-item:nth-child(2) { animation-delay: 0.08s; }
.track-item:nth-child(3) { animation-delay: 0.16s; }
.track-item:nth-child(4) { animation-delay: 0.24s; }
.track-item:nth-child(5) { animation-delay: 0.32s; }

/* 두 번째 줄 - 오른쪽에서 왼쪽으로 (역순) */
.track-item:nth-child(6) { animation-delay: 0.32s; }
.track-item:nth-child(7) { animation-delay: 0.24s; }
.track-item:nth-child(8) { animation-delay: 0.16s; }
.track-item:nth-child(9) { animation-delay: 0.08s; }
.track-item:nth-child(10) { animation-delay: 0s; }

/* 세 번째 줄 - 왼쪽에서 오른쪽으로 */
.track-item:nth-child(11) { animation-delay: 0s; }
.track-item:nth-child(12) { animation-delay: 0.08s; }
.track-item:nth-child(13) { animation-delay: 0.16s; }
.track-item:nth-child(14) { animation-delay: 0.24s; }
.track-item:nth-child(15) { animation-delay: 0.32s; }

@keyframes slideIn {
    0% {
        opacity: 0;
        transform: translateX(-100px) scale(0.5) rotate(-10deg);
    }
    60% {
        transform: translateX(10px) scale(1.1) rotate(2deg);
    }
    100% {
        opacity: 1;
        transform: translateX(0) scale(1) rotate(0);
    }
}

/* 두 번째 줄은 오른쪽에서 들어옴 */
.track-item:nth-child(6),
.track-item:nth-child(7),
.track-item:nth-child(8),
.track-item:nth-child(9),
.track-item:nth-child(10) {
    animation-name: slideInFromRight;
}

/* 세 번째 줄은 왼쪽에서 들어옴 */
.track-item:nth-child(n+11) {
    animation-name: slideIn;
}

@keyframes slideInFromRight {
    0% {
        opacity: 0;
        transform: translateX(100px) scale(0.5) rotate(10deg);
    }
    60% {
        transform: translateX(-10px) scale(1.1) rotate(-2deg);
    }
    100% {
        opacity: 1;
        transform: translateX(0) scale(1) rotate(0);
    }
}

.track-item.current {
    border: 3px solid #1db954;
    border-radius: 12px;
    padding: 8px;
    background: rgba(29, 185, 84, 0.15);
    box-shadow: 0 0 20px rgba(29, 185, 84, 0.4);
}

.track-item img {
    width: 140px;
    height: 140px;
    border-radius: 8px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, .6);
    object-fit: cover;
    background: rgba(255, 255, 255, .05);
    border: 1px solid rgba(255, 255, 255, .1);
    cursor: pointer;
    transition: transform .2s ease, box-shadow .2s ease;
    animation: subtleFloat 3s ease-in-out infinite;
}

/* 각 트랙마다 다른 타이밍으로 흔들림 */
.track-item:nth-child(1) img { animation-delay: 0s; }
.track-item:nth-child(2) img { animation-delay: 0.2s; }
.track-item:nth-child(3) img { animation-delay: 0.4s; }
.track-item:nth-child(4) img { animation-delay: 0.6s; }
.track-item:nth-child(5) img { animation-delay: 0.8s; }
.track-item:nth-child(6) img { animation-delay: 1.0s; }
.track-item:nth-child(7) img { animation-delay: 1.2s; }
.track-item:nth-child(8) img { animation-delay: 1.4s; }
.track-item:nth-child(9) img { animation-delay: 1.6s; }
.track-item:nth-child(10) img { animation-delay: 1.8s; }
.track-item:nth-child(11) img { animation-delay: 2.0s; }
.track-item:nth-child(12) img { animation-delay: 2.2s; }
.track-item:nth-child(13) img { animation-delay: 2.4s; }
.track-item:nth-child(14) img { animation-delay: 2.6s; }
.track-item:nth-child(15) img { animation-delay: 2.8s; }

@keyframes subtleFloat {
    0%, 100% {
        transform: translateY(0px) rotate(0deg);
    }
    25% {
        transform: translateY(-3px) rotate(0.5deg);
    }
    50% {
        transform: translateY(0px) rotate(0deg);
    }
    75% {
        transform: translateY(-2px) rotate(-0.5deg);
    }
}

.track-item img:hover {
    transform: scale(1.08) !important;
    box-shadow: 0 12px 30px rgba(0, 0, 0, .8);
    animation: none;
}

.track-item-info {
    margin-top: 8px;
    text-align: center;
    width: 140px;
}

.track-item-title {
    font-size: 13px;
    font-weight: 600;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    color: #fff;
}

.track-item-artist {
    font-size: 11px;
    opacity: 0.7;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    margin-top: 4px;
}

.album-cover.hidden {
    display: none !important;
}

.album-cover[src=""],
.album-cover:not([src]) {
    display: none
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: scale(.95)
    }

    to {
        opacity: 1;
        transform: scale(1)
    }
}

.track-name {
    font-weight: 600;
    margin-bottom: 5px
}

.artist-name {
    opacity: .8;
    font-size: 12px
}

.space-background {
    position: fixed;
    inset: 0;
    background: radial-gradient(ellipse at bottom, #1B2735 0%, #090A0F 100%);
    z-index: -2
}

.stars {
    position: fixed;
    inset: 0;
    z-index: -1
}

.star {
    position: absolute;
    background: #fff;
    border-radius: 50%;
    animation: twinkle 2s infinite
}

.star.small {
    width: 1px;
    height: 1px
}

.star.medium {
    width: 2px;
    height: 2px
}

.star.large {
    width: 3px;
    height: 3px
}

@keyframes twinkle {

    0%,
    100% {
        opacity: .3
    }

    50% {
        opacity: 1
    }
}

.dust {
    position: absolute;
    background: rgba(255, 255, 255, .1);
    border-radius: 50%;
    animation: float 10s infinite linear
}

@keyframes float {
    0% {
        transform: translateY(100vh) translateX(0)
    }

    100% {
        transform: translateY(-100px) translateX(50px)
    }
}

.hidden {
    display: none !important
}

.error-message {
    color: #ff6b6b;
    text-align: center;
    margin-top: 20px
}

.github-link {
    position: fixed;
    top: 20px;
    right: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    color: #fff;
    text-decoration: none;
    background: rgba(255, 255, 255, .1);
    padding: 10px 15px;
    border-radius: 20px;
    font-size: 14px;
    transition: .3s;
    border: 1px solid rgba(255, 255, 255, .2);
    backdrop-filter: blur(10px)
}

.github-link:hover {
    background: rgba(255, 255, 255, .2);
    transform: translateY(-2px);
    color: #fff
}

.search-interface {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: linear-gradient(135deg, rgba(20, 20, 20, 0.95) 0%, rgba(0, 0, 0, 0.98) 100%);
    padding: 15px 18px;
    border-radius: 12px;
    color: #fff;
    text-align: center;
    max-width: 360px;
    width: 80%;
    box-shadow:
        0 15px 40px rgba(0, 0, 0, 0.6),
        0 5px 15px rgba(0, 0, 0, 0.4),
        inset 0 1px 0 rgba(255, 255, 255, 0.1),
        inset 0 -1px 0 rgba(0, 0, 0, 0.5);
    border: 1px solid rgba(255, 255, 255, .15);
    border-top: 1px solid rgba(255, 255, 255, .2);
    backdrop-filter: blur(15px);
    z-index: 100;
}

.search-interface h2 {
    margin: 0 0 12px 0;
    font-size: 16px;
}

.search-section {
    margin-bottom: 10px;
}

.search-input {
    width: 100%;
    padding: 10px 14px;
    margin: 0 0 8px 0;
    border: 2px solid rgba(255, 255, 255, .3);
    border-radius: 20px;
    background: rgba(255, 255, 255, .1);
    color: #fff;
    font-size: 13px;
    outline: none;
    transition: .3s;
    box-sizing: border-box;
}

.search-input:focus {
    border-color: #1db954;
}

.search-input::placeholder {
    color: rgba(255, 255, 255, .5);
    font-size: 12px;
}

.search-input:focus {
    border-color: #1db954
}

.search-input::placeholder {
    color: rgba(255, 255, 255, .6)
}

.search-button {
    background: linear-gradient(135deg, #1ed760 0%, #1db954 100%);
    color: #fff;
    border: none;
    padding: 9px 20px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all .2s ease;
    margin-bottom: 5px;
    box-shadow:
        0 4px 15px rgba(29, 185, 84, 0.4),
        0 2px 4px rgba(0, 0, 0, 0.3),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
    position: relative;
    transform: translateY(0);
}

.search-button:hover {
    background: linear-gradient(135deg, #1fdf6b 0%, #1ed760 100%);
    box-shadow:
        0 6px 20px rgba(29, 185, 84, 0.5),
        0 3px 6px rgba(0, 0, 0, 0.4),
        inset 0 1px 0 rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.search-button:active {
    transform: translateY(0);
    box-shadow:
        0 2px 8px rgba(29, 185, 84, 0.3),
        0 1px 2px rgba(0, 0, 0, 0.2),
        inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

.search-button:disabled {
    background: linear-gradient(135deg, #888 0%, #666 100%);
    cursor: not-allowed;
    box-shadow:
        0 2px 8px rgba(0, 0, 0, 0.2),
        inset 0 1px 0 rgba(255, 255, 255, 0.1);
    transform: translateY(0);
}

.recommendation-list {
    margin-top: 20px;
    max-height: 300px;
    overflow-y: auto;
    text-align: left
}

.recommendation-item {
    background: rgba(255, 255, 255, .1);
    margin: 10px 0;
    padding: 15px;
    border-radius: 10px;
    cursor: pointer;
    transition: .3s;
    border: 1px solid rgba(255, 255, 255, .1);
    display: flex;
    align-items: center;
    gap: 12px
}

.recommendation-item:hover {
    background: rgba(255, 255, 255, .2)
}

.recommendation-item.selected {
    background: rgba(29, 185, 84, .3);
    border-color: #1db954
}

.rec-album-cover {
    width: 50px;
    height: 50px;
    border-radius: 4px;
    object-fit: cover;
    background: rgba(255, 255, 255, .05);
    flex-shrink: 0;
    display: block
}

.rec-album-cover[src=""],
.rec-album-cover:not([src]) {
    display: none
}

.rec-info {
    flex: 1;
    min-width: 0
}

.rec-title {
    font-weight: 600;
    color: #fff;
    margin-bottom: 5px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis
}

.rec-artist {
    color: rgba(255, 255, 255, .8);
    font-size: 14px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis
}