:root {
    --bg-main: #0f172a;
    --bg-card: #1e293b;
    --bg-card-hover: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #0ea5e9;
    --accent-hover: #0284c7;
    --success-color: #10b981;
    --border-color: #334155;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header & Nav */
header {
    background-color: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: 20px 0;
}

.header-container {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    gap: 30px;
}

.logo h1 {
    font-size: 4.5rem;
    font-weight: 700;
}

.logo span {
    color: var(--accent-color);
}

.tab-nav {
    display: flex;
    gap: 10px;
}

.tab-btn {
    border: none;
    padding: 15px 30px;
    font-size: 1.1rem;
    font-weight: 700;
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.2s ease, opacity 0.2s ease;
}

.tab-btn:hover {
    transform: translateY(-2px);
    opacity: 0.9;
}

.tab-btn.active {
    box-shadow: 0 0 0 4px rgba(255,255,255,0.2);
}

.tab-btn:nth-child(1) {
    background-color: #facc15; /* Yellow */
    color: #000;
}

.tab-btn:nth-child(2) {
    background-color: #ef4444; /* Red */
    color: #fff;
}

.tab-btn:nth-child(3) {
    background-color: #3b82f6; /* Blue */
    color: #fff;
}

/* Main Layout */
.main-layout {
    display: flex;
    gap: 40px;
    padding: 40px 20px;
    flex-grow: 1;
}

.content-area {
    flex-grow: 1;
    max-width: 800px;
}

/* Ads */
.ad-zone {
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px dashed var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.top-ad {
    width: 100%;
    height: 90px;
    margin-bottom: 0;
    border-top: none;
    border-left: none;
    border-right: none;
}

.vertical-ad {
    width: 300px;
    height: 600px;
    position: sticky;
    top: 40px;
}

.action-ad {
    width: 100%;
    height: 90px;
    margin-top: 30px;
}

@media (max-width: 900px) {
    .main-layout {
        flex-direction: column-reverse;
    }
    .vertical-ad {
        width: 100%;
        height: 100px;
        position: static;
    }
}

/* Tab Content */
.tab-content {
    display: none;
    background-color: var(--bg-card);
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.tab-content h2 {
    font-size: 1.8rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.tab-content p {
    color: var(--text-secondary);
    margin-bottom: 30px;
}

/* Upload Zone */
.upload-zone {
    border: 2px dashed var(--border-color);
    border-radius: 12px;
    padding: 50px 20px;
    text-align: center;
    background-color: rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
    margin-bottom: 20px;
}

.upload-zone.dragover {
    border-color: var(--accent-color);
    background-color: rgba(14, 165, 233, 0.1);
}

.upload-zone p {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.upload-zone span {
    display: block;
    margin-bottom: 15px;
    color: var(--text-secondary);
}

.btn-primary {
    display: inline-block;
    background-color: var(--accent-color);
    color: white;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
}

/* Controls */
.controls {
    margin-bottom: 30px;
}

.split-controls {
    display: flex;
    gap: 20px;
}

.split-controls > div {
    flex: 1;
}

label {
    display: block;
    margin-bottom: 8px;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

select, input[type="number"] {
    width: 100%;
    padding: 12px;
    background-color: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: 8px;
    font-size: 1rem;
    outline: none;
}

select:focus, input[type="number"]:focus {
    border-color: var(--accent-color);
}

/* Buttons */
.btn-action {
    width: 100%;
    background-color: var(--success-color);
    color: white;
    padding: 15px;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: opacity 0.3s ease;
}

.btn-action:hover {
    opacity: 0.9;
}

.btn-action:disabled {
    background-color: var(--border-color);
    color: var(--text-secondary);
    cursor: not-allowed;
}

/* Status & File Lists */
.status-msg {
    margin-top: 10px;
    font-size: 0.9rem;
    color: var(--accent-color);
    font-weight: 600;
    min-height: 20px;
    text-align: center;
}

.file-list {
    margin-bottom: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.file-item {
    background-color: var(--bg-main);
    padding: 10px 15px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid var(--border-color);
}

.file-item button {
    background: transparent;
    border: none;
    color: #ef4444;
    cursor: pointer;
    font-weight: bold;
}

/* Footer */
footer {
    background-color: var(--bg-card);
    border-top: 1px solid var(--border-color);
    padding: 30px 0;
    margin-top: auto;
}

.footer-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    text-align: center;
}

.footer-links {
    display: flex;
    gap: 20px;
}

.footer-links a {
    color: var(--accent-color);
    text-decoration: none;
}

.footer-links a:hover {
    text-decoration: underline;
}

.footer-container p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Instructions */
.instructions {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.instructions h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    font-size: 1.2rem;
}

.instructions ol {
    padding-left: 20px;
    color: var(--text-secondary);
}

.instructions li {
    margin-bottom: 8px;
}