:root {
    /* Dark Mode (Energetic Neon) */
    --bg-color: #0a0612;
    --card-bg: #161122;
    --accent-color: #fb2858; /* Electric Pink */
    --accent-gradient: linear-gradient(135deg, #fb2858 0%, #5828fb 100%);
    --text-primary: #ffffff;
    --text-secondary: #a5a1b2;
    --input-bg: #1c162d;
    --input-border: #2d2445;
    --transition-speed: 0.25s;
}

[data-theme="light"] {
    --bg-color: #ffffff;
    --card-bg: #f8fafc;
    --accent-color: #0ea5e9; /* Vibrant Cyan */
    --accent-gradient: linear-gradient(135deg, #0ea5e9 0%, #6366f1 100%);
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --input-bg: #ffffff;
    --input-border: #e2e8f0;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 20px;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

#app {
    width: 100%;
    max-width: 600px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px 0;
}

/* Theme Toggle Switch */
.theme-switch-wrapper {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 10px;
    margin-bottom: 20px;
}

.theme-switch-wrapper span {
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--text-secondary);
}

.switch {
    display: inline-block;
    height: 26px;
    position: relative;
    width: 50px;
}

.switch input {
    display:none;
}

.slider {
    background-color: var(--input-border);
    bottom: 0;
    cursor: pointer;
    left: 0;
    position: absolute;
    right: 0;
    top: 0;
    transition: .4s;
    border-radius: 34px;
}

.slider:before {
    background-color: #fff;
    bottom: 4px;
    content: "";
    height: 18px;
    left: 4px;
    position: absolute;
    transition: .4s;
    width: 18px;
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

input:checked + .slider {
    background: var(--accent-gradient);
}

input:checked + .slider:before {
    transform: translateX(24px);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 12px;
}

.logo-icon {
    color: var(--accent-color);
    filter: drop-shadow(0 0 8px var(--accent-color));
}

header h1 {
    font-size: 3rem;
    font-weight: 900;
    letter-spacing: -0.04em;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 500;
}

.search-container {
    display: flex;
    gap: 12px;
    margin-bottom: 40px;
}

input[type="text"], .filter-select, .numeric-input-wrapper {
    background: var(--input-bg);
    border: 2px solid var(--input-border);
    border-radius: 12px;
    padding: 16px 20px;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 500;
    transition: all var(--transition-speed);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.numeric-input-wrapper {
    display: flex;
    align-items: center;
    padding: 2px;
    height: 60px;
}

.numeric-input-wrapper:focus-within {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(251, 40, 88, 0.15);
}

.numeric-input {
    flex: 1;
    background: transparent;
    border: none;
    text-align: center;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-weight: 700;
    width: 100%;
    -moz-appearance: textfield;
}

.numeric-input::-webkit-outer-spin-button,
.numeric-input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.numeric-input:focus {
    outline: none;
}

.numeric-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1.5rem;
    font-weight: 400;
    cursor: pointer;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    transition: all var(--transition-speed);
    box-shadow: none;
}

.numeric-btn:hover {
    color: var(--accent-color);
    background: rgba(251, 40, 88, 0.1);
    transform: none;
    box-shadow: none;
    filter: none;
}

.numeric-btn:active {
    transform: scale(0.92);
}

input[type="text"] {
    flex: 2;
}

.filter-select {
    flex: 1;
    cursor: pointer;
    -webkit-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='hotpink' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 1.2rem center;
    background-size: 1.1em;
    padding-right: 3rem;
}

[data-theme="light"] .filter-select {
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%230ea5e9' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
}

input[type="text"]:focus, .filter-select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(251, 40, 88, 0.15);
}

button {
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: 12px;
    padding: 0 28px;
    font-weight: 800;
    font-size: 1.05rem;
    cursor: pointer;
    transition: all var(--transition-speed);
    box-shadow: 0 4px 14px 0 rgba(251, 40, 88, 0.39);
}

button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(251, 40, 88, 0.45);
    filter: brightness(1.1);
}

button:active {
    transform: translateY(0);
}

.icon-button {
    background: var(--input-bg);
    color: var(--text-secondary);
    padding: 0 15px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--input-border);
}

.icon-button:hover {
    color: var(--accent-color);
    border-color: var(--accent-color);
    background: var(--bg-color);
}

.results-container {
    animation: fadeIn 0.6s cubic-bezier(0.22, 1, 0.36, 1);
}

.hidden {
    display: none;
}

.results-header {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 25px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--input-border);
}

.results-header h2 {
    font-size: 1.8rem;
    font-weight: 900;
    letter-spacing: -0.03em;
}

.results-actions {
    display: flex;
    gap: 12px;
    width: 100%;
}

.spotify-button {
    background: #1DB954;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 12px 20px;
    font-weight: 700;
    border-radius: 12px;
    box-shadow: 0 4px 14px rgba(29, 185, 84, 0.25);
}

.spotify-button:disabled {
    opacity: 0.8;
    cursor: wait;
    filter: grayscale(0.2);
}

.spinner-inline {
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255,255,255,0.3);
    border-top: 2px solid #ffffff;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    display: inline-block;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.spotify-button.small {
    padding: 8px 16px;
    font-size: 0.85rem;
    border-radius: 30px;
    flex: 0 1 auto;
}

.spotify-color {
    color: #1DB954 !important;
}

.secondary-button {
    background: var(--card-bg);
    border: 2px solid var(--input-border);
    color: var(--text-primary);
    padding: 12px;
    box-shadow: none;
}

.secondary-button:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
    background: transparent;
    box-shadow: none;
}

.status-message {
    text-align: center;
    padding: 12px 20px;
    border-radius: 12px;
    font-size: 0.95rem;
    font-weight: 700;
    width: 100%;
}

.status-message.success {
    background: rgba(16, 185, 129, 0.1);
    color: #10b981;
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.status-message.error {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.artists-grid {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.artist-card {
    background: var(--card-bg);
    padding: 20px 24px;
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    border: 1px solid var(--input-border);
    transition: transform var(--transition-speed);
}

.artist-card:hover {
    transform: scale(1.01);
}

.artist-info {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 15px;
}

.artist-name {
    font-size: 1.25rem;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.tracks-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 5px;
}

.track-link {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    padding: 8px 12px;
    background: rgba(255,255,255,0.03);
    border-radius: 8px;
    transition: all var(--transition-speed);
}

[data-theme="light"] .track-link {
    background: rgba(0,0,0,0.03);
}

.track-link:hover {
    color: var(--text-primary);
    background: rgba(251, 40, 88, 0.1);
}

.track-icon {
    display: flex;
    align-items: center;
}

footer {
    text-align: center;
    margin-top: 80px;
    padding-bottom: 40px;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 600;
}

.footer-nav {
    margin-top: 15px;
    display: flex;
    justify-content: center;
    gap: 20px;
}

.footer-nav a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color var(--transition-speed);
}

.footer-nav a:hover {
    color: var(--accent-color);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 480px) {
    header h1 { font-size: 2.2rem; }
    .search-container { flex-direction: column; }
    .results-actions { flex-direction: column; }
}