:root {
    /* Color Palette */
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --pro-color: #f59e0b;
    
    /* Light Theme (Default) */
    --bg-color: #f8fafc;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.5);
    --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.07);
    --zone-border: #cbd5e1;
    --zone-bg-hover: #f1f5f9;
    --table-border: #e2e8f0;
    --table-header-bg: #f8fafc;
}

[data-theme="dark"] {
    /* Dark Theme */
    --bg-color: #0f172a;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    --zone-border: #475569;
    --zone-bg-hover: #1e293b;
    --table-border: #334155;
    --table-header-bg: #0f172a;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
    position: relative;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Background Blobs for Visual Interest */
.background-blobs {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

.blob {
    position: absolute;
    filter: blur(80px);
    opacity: 0.5;
    border-radius: 50%;
    animation: float 20s infinite ease-in-out;
}

.blob-1 {
    top: -10%;
    left: -10%;
    width: 50vw;
    height: 50vw;
    background: radial-gradient(circle, rgba(99,102,241,0.3) 0%, rgba(99,102,241,0) 70%);
}

.blob-2 {
    bottom: -10%;
    right: -10%;
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, rgba(236,72,153,0.2) 0%, rgba(236,72,153,0) 70%);
    animation-delay: -10s;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(5%, 10%) scale(1.1); }
    66% { transform: translate(-5%, 5%) scale(0.9); }
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.2rem;
}

.logo h1 {
    font-weight: 700;
}

.logo .highlight {
    color: var(--primary);
}

.actions {
    display: flex;
    gap: 1rem;
}

/* Buttons */
.btn {
    font-family: inherit;
    font-weight: 600;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-secondary {
    background-color: var(--glass-bg);
    color: var(--text-main);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(4px);
}

.btn-secondary:hover {
    background-color: var(--zone-bg-hover);
}

.btn-pro {
    background-color: transparent;
    color: var(--pro-color);
    border: 1px solid var(--pro-color);
}

.btn-pro:hover {
    background-color: var(--pro-color);
    color: #fff;
}

.btn-icon {
    background: transparent;
    font-size: 1.2rem;
    padding: 0.5rem;
    color: var(--text-main);
}

/* Main Container */
.container {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem 5%;
    max-width: 1000px;
    margin: 0 auto;
    width: 100%;
    gap: 2rem;
}

/* Glassmorphism Card */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    border-radius: 1rem;
    width: 100%;
    overflow: hidden;
}

.main-converter {
    display: flex;
    flex-direction: column;
}

/* Tabs */
.tabs {
    display: flex;
    border-bottom: 1px solid var(--glass-border);
}

.tab {
    flex: 1;
    padding: 1rem;
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    border-bottom: 2px solid transparent;
}

.tab:hover {
    color: var(--text-main);
    background-color: rgba(0,0,0,0.02);
}

.tab.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
    background-color: rgba(99,102,241,0.05);
}

/* Converter Body */
.converter-body {
    padding: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    position: relative;
}

/* Options */
.options-bar {
    display: flex;
    gap: 1.5rem;
}

.option-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.glass-select {
    padding: 0.4rem 0.8rem;
    border-radius: 0.5rem;
    border: 1px solid var(--glass-border);
    background-color: var(--glass-bg);
    color: var(--text-main);
    font-family: inherit;
    cursor: pointer;
    outline: none;
}

/* Drop Zone */
.drop-zone {
    border: 2px dashed var(--zone-border);
    border-radius: 1rem;
    padding: 4rem 2rem;
    text-align: center;
    transition: all 0.2s ease;
    cursor: pointer;
    background-color: rgba(0,0,0,0.02);
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--primary);
    background-color: var(--zone-bg-hover);
}

.drop-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.drop-icon {
    font-size: 3rem;
    opacity: 0.8;
}

.file-limits {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
}

/* Loading Overlay */
.loading-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: var(--glass-bg);
    backdrop-filter: blur(4px);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    z-index: 10;
    border-radius: 0 0 1rem 1rem;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--zone-border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Result Section */
.result-section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    animation: fadeIn 0.3s ease;
}

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

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.result-actions {
    display: flex;
    gap: 0.5rem;
}

/* Table Preview */
.table-container {
    width: 100%;
    overflow-x: auto;
    border: 1px solid var(--table-border);
    border-radius: 0.5rem;
    max-height: 300px;
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
    font-size: 0.9rem;
}

th, td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--table-border);
    white-space: nowrap;
}

th {
    background-color: var(--table-header-bg);
    font-weight: 600;
    position: sticky;
    top: 0;
}

/* JSON Preview */
.textarea-container textarea {
    width: 100%;
    height: 300px;
    padding: 1rem;
    border-radius: 0.5rem;
    border: 1px solid var(--table-border);
    background-color: var(--glass-bg);
    color: var(--text-main);
    font-family: monospace;
    resize: vertical;
    outline: none;
}

/* Ad Container Placeholder */
.ad-container {
    width: 100%;
    max-width: 728px;
    height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Footer */
.app-footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Utility Classes */
[hidden] {
    display: none !important;
}

/* Responsive */
@media (max-width: 600px) {
    .app-header {
        flex-direction: column;
        gap: 1rem;
        padding: 1rem;
    }
    .drop-zone {
        padding: 2rem 1rem;
    }
    .result-header {
        flex-direction: column;
        align-items: flex-start;
    }
    .options-bar {
        flex-direction: column;
        gap: 1rem;
    }
    .modal {
        margin: 1rem;
        padding: 1.5rem;
        max-height: 90vh;
        overflow-y: auto;
    }
    .modal h2 {
        font-size: 1.3rem;
    }
    .modal-pricing {
        flex-direction: column;
        gap: 1rem;
    }
    .price {
        font-size: 2rem;
    }
}

/* Pro Modal */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(6px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    animation: fadeIn 0.2s ease;
}

.modal {
    max-width: 520px;
    width: 100%;
    padding: 2.5rem;
    position: relative;
    text-align: center;
    max-height: 95vh;
    overflow-y: auto;
}

.modal h2 {
    font-size: 1.6rem;
    margin-bottom: 0.5rem;
}

.modal-subtitle {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

.modal-close {
    position: absolute;
    top: 1rem;
    right: 1.2rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: color 0.2s;
}

.modal-close:hover {
    color: var(--text-main);
}

.modal-features {
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
    margin-bottom: 2rem;
}

.feature-item {
    font-size: 0.95rem;
    padding: 0.4rem 0;
}

.modal-pricing {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.price-option {
    text-align: center;
}

.price {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary);
}

.price-period {
    font-size: 1rem;
    color: var(--text-muted);
}

.price-option p {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.price-divider {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.btn-lg {
    padding: 0.8rem 2rem;
    font-size: 1.1rem;
    width: 100%;
    text-decoration: none;
    margin-bottom: 0.75rem;
}

.modal-note {
    font-size: 0.8rem;
    color: var(--text-muted);
}