:root {
    --bg-gradient-start: #FFFFFF;
    --bg-gradient-end: #F0F2F5;
    --panel-bg: #FFFFFF;
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --accent-color: #4FD1C5;
    --accent-hover: #38B2AC;
    --danger-color: #f56565;
    --danger-hover: #e53e3e;
    --border-color: #e2e8f0;
    --shadow-color: rgba(0, 0, 0, 0.05);
    --font-family: 'Poppins', sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: linear-gradient(135deg, var(--bg-gradient-start), var(--bg-gradient-end));
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.app-container {
    max-width: 1600px;
    margin: 0 auto;
    padding: 2rem;
}

/* Hero Section */
.hero-section {
    text-align: center;
    padding: 3rem 1rem;
    margin-bottom: 2rem;
    position: relative;
}

.header-nav {
    position: absolute;
    top: 1.5rem;
    right: 2rem;
}

#how-it-works-link {
    font-weight: 600;
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}

#how-it-works-link:hover {
    color: var(--accent-color);
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.cta-button {
    font-family: var(--font-family);
    font-size: 1.1rem;
    font-weight: 600;
    color: white;
    background-color: var(--accent-color);
    border: none;
    border-radius: 50px;
    padding: 0.8rem 2.5rem;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
    box-shadow: 0 4px 15px rgba(79, 209, 197, 0.4);
}

.cta-button:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(79, 209, 197, 0.5);
}

/* Editor Grid Layout */
.editor-grid {
    display: grid;
    grid-template-columns: 300px 1fr 300px;
    gap: 1.5rem;
    align-items: start;
}

.panel {
    background: var(--panel-bg);
    border-radius: 12px;
    box-shadow: 0 8px 32px var(--shadow-color);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
}

.panel-section {
    margin-bottom: 2rem;
}
.panel-section:last-child {
    margin-bottom: 0;
}

.panel-title {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

/* Controls */
.button-group {
    display: flex;
    gap: 0.5rem;
}
.aspect-btn {
    flex: 1;
    font-family: var(--font-family);
    font-size: 0.9rem;
    padding: 0.6rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background-color: #fff;
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 600;
    color: var(--text-secondary);
}
.aspect-btn.active {
    background-color: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}


.control-buttons {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.75rem;
}

.control-btn {
    font-family: var(--font-family);
    font-size: 0.95rem;
    padding: 0.75rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background-color: #fff;
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 600;
    color: var(--text-secondary);
}

.control-btn:hover {
    background-color: #f7fafc;
    border-color: #cbd5e0;
    color: var(--text-primary);
}

.control-btn.record-btn {
    background-color: #fefcbf;
    color: #92400e;
}

.control-btn.download-btn {
    background-color: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}
.control-btn.download-btn:disabled {
    background-color: #a0aec0;
    cursor: not-allowed;
}

.control-btn.danger {
    background-color: #fed7d7;
    color: #9b2c2c;
}
.control-btn.danger:hover {
    background-color: var(--danger-color);
    color: white;
}

/* Media Library */
.media-library {
    min-height: 100px;
}
.placeholder-text {
    color: var(--text-secondary);
    text-align: center;
    padding: 1rem;
}
.media-item {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
    padding: 8px;
    border-radius: 6px;
    background-color: #f7fafc;
}
.media-item img {
    width: 60px;
    height: 40px;
    object-fit: cover;
    border-radius: 4px;
}
.media-item .duration-control {
    display: flex;
    align-items: center;
    gap: 5px;
}
.media-item input[type="number"] {
    width: 60px;
    padding: 5px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

/* Center Stage */
.canvas-container {
    position: relative;
    width: 100%;
    padding-top: 56.25%; /* 16:9 Aspect Ratio */
    background: #1a202c;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    transition: padding-top 0.3s ease;
}
.canvas-container.portrait {
    padding-top: 177.78%; /* 9:16 Aspect Ratio */
}
#preview-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}
.timeline-controls {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--panel-bg);
    border-radius: 12px;
    box-shadow: 0 8px 32px var(--shadow-color);
}
.timeline-slider {
    -webkit-appearance: none;
    width: 100%;
    height: 8px;
    background: #e2e8f0;
    outline: none;
    border-radius: 4px;
    transition: opacity .2s;
}
.timeline-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-color);
    cursor: pointer;
    border-radius: 50%;
}
.timeline-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

/* Properties Panel */
.property-group {
    margin-bottom: 1rem;
}
.property-group label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}
.property-group input, .property-group select {
    width: 100%;
    padding: 0.5rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    font-family: var(--font-family);
}
.property-group input[type="color"] {
    height: 40px;
    padding: 5px;
}

.hidden {
    display: none !important;
}

/* Footer */
.app-footer {
    text-align: center;
    margin-top: 3rem;
    padding: 2rem;
    border-top: 1px solid var(--border-color);
}
.instructions-panel {
    text-align: left;
    max-width: 800px;
    margin: 0 auto 3rem auto;
    padding: 1.5rem 2rem;
    background: var(--panel-bg);
    border-radius: 12px;
    box-shadow: 0 8px 32px var(--shadow-color);
    border: 1px solid var(--border-color);
}
.instructions-panel ol {
    padding-left: 20px;
}
.instructions-panel li {
    margin-bottom: 0.75rem;
}
.share-section p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}
.social-links a {
    color: var(--accent-color);
    text-decoration: none;
    margin: 0 0.5rem;
    font-weight: 600;
    transition: color 0.2s;
}
.social-links a:hover {
    color: var(--accent-hover);
}
.convert-banner {
    margin-top: 2rem;
    padding: 1.5rem;
    background-color: #ebf8ff;
    border-radius: 12px;
    display: inline-block;
}

/* Responsiveness */
@media (max-width: 1200px) {
    .editor-grid {
        grid-template-columns: 250px 1fr 250px;
    }
}

@media (max-width: 992px) {
    .editor-grid {
        grid-template-columns: 1fr;
    }
    .left-panel {
        order: 2;
    }
    .center-stage {
        order: 1;
    }
    .right-panel {
        order: 3;
        width: 100%;
    }
    .properties-panel:not(.hidden) {
        display: block !important;
    }
    .canvas-container.portrait {
       max-width: 350px; /* Limit portrait canvas size on tablets */
       margin: 0 auto;
    }
}

@media (max-width: 576px) {
    .app-container {
        padding: 1rem;
    }
    .hero-title {
        font-size: 2.5rem;
    }
    .header-nav {
        top: 1rem;
        right: 1rem;
    }
}