:root {
    --bg-color: #0f0f0f;
    --text-color: #ffffff;
    --border-color: #2d2d2d;
    --primary-color: #ffffff;
    --grid-line-color: rgba(255, 255, 255, 0.1);
    --grid-border-color: #2d2d2d;
    --modal-bg: #1a1a1a;
    --hover-color: rgba(255, 255, 255, 0.1);
    --button-hover: rgba(255, 255, 255, 0.15);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    line-height: 1.5;
}

.header {
    display: flex;
    align-items: center;
    padding: 1rem 1.5rem;
    background-color: var(--modal-bg);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    gap: 1.5rem;
}

.title {
    font-size: 1.75rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-color);
    margin-right: auto;
}

button {
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    font-size: 1rem;
    transition: background-color 0.2s;
}

button:hover {
    background-color: var(--button-hover);
}

.grid-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-auto-rows: minmax(150px, auto);
    gap: 1rem;
    padding: 1rem;
    min-height: calc(100vh - 60px);
}

.grid-cell {
    position: relative;
    border: 1px solid var(--border-color);
    aspect-ratio: 16/9;
    background-color: var(--modal-bg);
    border-radius: 8px;
    overflow: hidden;
    transition: border-color 0.2s;
}

.grid-cell:hover {
    border-color: var(--primary-color);
}

.add-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 48px;
    height: 48px;
    background-color: var(--hover-color);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--text-color);
    cursor: pointer;
    transition: all 0.2s;
}

.add-button:hover {
    background-color: var(--button-hover);
    border-color: var(--primary-color);
    transform: translate(-50%, -50%) scale(1.1);
}

.video-wrapper {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: var(--modal-bg);
    display: flex;
    flex-direction: column;
}

.video-wrapper::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 40px;
    height: 40px;
    margin: -20px 0 0 -20px;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: loading 0.8s linear infinite;
    z-index: 1;
    pointer-events: none; /* do not block video interactions */
}

.video-wrapper.loaded::before {
    display: none;
}

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

.video-player {
    width: 100%;
    height: auto;
    border: none;
    flex: 1 1 auto;
}

video {
    width: 100%;
    height: auto;
    object-fit: cover;
    flex: 1 1 auto;
}

/* Drag handle bar */
.drag-handle {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 28px;
    background: linear-gradient(180deg, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0.3) 70%, transparent 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
    opacity: 0;
    transition: opacity 0.2s;
    z-index: 15;
    color: rgba(255,255,255,0.7);
    font-size: 1rem;
    letter-spacing: 2px;
    user-select: none;
}

.video-wrapper:hover .drag-handle {
    opacity: 1;
}

.drag-handle:active {
    cursor: grabbing;
}

.video-wrapper.dragging {
    opacity: 0.5;
}

.grid-cell.drag-over {
    outline: 3px dashed #2ecc71;
    outline-offset: -3px;
}

.remove-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    background: rgba(255, 68, 68, 0.8);
    color: white;
    border: none;
    border-radius: 50%;
    width: 28px;
    height: 28px;
    cursor: pointer;
    opacity: 0;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    z-index: 10;
    padding: 0;
}

.video-wrapper:hover .remove-btn {
    opacity: 1;
}

.remove-btn:hover {
    background: rgb(255, 68, 68);
    transform: scale(1.1);
}

/* =========================
   YouTube control buttons
   ========================= */
.yt-controls {
    display: flex;
    gap: 0.75rem;
    padding: 0.75rem;
    background: rgba(0, 0, 0, 0.75);
    justify-content: center;
    align-items: center;
    flex: 0 0 auto;
    flex-wrap: wrap;
    z-index: 5;
}

.yt-btn {
    color: #000;
    font-weight: 700;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    padding: 0.75rem 1rem;
    min-width: 130px;
    font-size: 1.02rem;
    line-height: 1;
    transition: transform 0.15s ease, filter 0.15s ease;
}

.yt-btn:active { transform: scale(0.98); }
.yt-btn:hover { filter: brightness(0.95); }

.yt-play { background: #2ecc71; /* green */ }
.yt-restart { background: #e74c3c; /* red */ }
.yt-mute { background: #f1c40f; /* yellow */ }
.yt-fadeout { background: #3498db; /* blue */ }
.yt-fadein { background: #9b59b6; /* purple */ }

/* Controls toggle button */
.yt-controls-toggle {
    position: absolute;
    bottom: 0.5rem;
    right: 0.5rem;
    background: rgba(0, 0, 0, 0.8);
    color: #fff;
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: 4px;
    padding: 0.3rem 0.6rem;
    font-size: 0.7rem;
    cursor: pointer;
    z-index: 20;
    opacity: 0;
    transition: opacity 0.2s;
}

.video-wrapper:hover .yt-controls-toggle {
    opacity: 1;
}

.yt-controls-toggle:hover {
    background: rgba(0, 0, 0, 0.95);
    border-color: rgba(255,255,255,0.5);
}

/* Collapsed controls */
.yt-controls.collapsed {
    display: none;
}

.video-error {
    display: none;
}

.grid-cell.empty {
    display: flex;
    align-items: center;
    justify-content: center;
}

.grid-cell.empty .video-wrapper {
    display: none;
}

.grid-cell.empty .add-button {
    display: flex;
}

/* Modal Styling */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 2000;
    backdrop-filter: blur(4px);
}

.modal-content {
    background: var(--modal-bg);
    margin: 2rem auto;
    padding: 2rem;
    width: 90%;
    max-width: 500px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    position: relative;
    max-height: calc(100vh - 4rem);
    overflow-y: auto;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.close-modal {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: transparent;
    border: none;
    font-size: 1.5rem;
    color: var(--text-color);
    cursor: pointer;
    padding: 0.5rem;
    line-height: 1;
    opacity: 0.7;
    transition: all 0.2s;
}

.close-modal:hover {
    opacity: 1;
    transform: scale(1.1);
}

.modal h2 {
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    font-weight: 600;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

input[type="text"],
input[type="url"] {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 0.8rem 1rem;
    border-radius: 6px;
    font-size: 1rem;
    width: 100%;
    transition: all 0.2s;
}

input[type="text"]:focus,
input[type="url"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.file-upload {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    border: 2px dashed var(--border-color);
    padding: 2rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    background: var(--bg-color);
}

.file-upload:hover {
    border-color: var(--primary-color);
    background: var(--hover-color);
}

.file-upload input[type="file"] {
    display: none;
}

.file-label {
    color: var(--primary-color);
    font-weight: 500;
    cursor: pointer;
}

#fileName {
    font-size: 0.9rem;
    opacity: 0.7;
}

.primary-btn {
    background: var(--primary-color);
    color: var(--bg-color);
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: all 0.2s;
    width: 100%;
}

.primary-btn:hover {
    opacity: 0.9;
    transform: translateY(-1px);
}