/* Root Variables */
:root {
    --rich-black: #04080F;
    --glaucous: #507DBC;
    --powder-blue: #A1C6EA;
    --ghost-white: #F0F7FF;
    --columbia-blue: #BBD1EA;
    --success-green: #10B981;
    --warning-orange: #F59E0B;
    --error-red: #EF4444;
}

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

body {
    font-family: 'Play', sans-serif;
    background: linear-gradient(135deg, var(--rich-black) 0%, #0a1628 100%);
    color: var(--ghost-white);
    min-height: 100vh;
    line-height: 1.6;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 40px;
    padding: 40px 20px;
    background: linear-gradient(135deg, rgba(80, 125, 188, 0.1) 0%, rgba(161, 198, 234, 0.05) 100%);
    border-radius: 20px;
    border: 1px solid rgba(80, 125, 188, 0.2);
}

.header h1 {
    font-size: 2.5rem;
    background: linear-gradient(135deg, var(--powder-blue) 0%, var(--glaucous) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 15px;
    font-weight: 700;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--columbia-blue);
    margin-bottom: 10px;
}

.header-description {
    color: var(--powder-blue);
    opacity: 0.8;
}

/* Tabs */
.converter-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    background: rgba(80, 125, 188, 0.1);
    padding: 5px;
    border-radius: 15px;
}

.tab-btn {
    flex: 1;
    padding: 15px 20px;
    font-size: 1.1rem;
    font-family: 'Play', sans-serif;
    font-weight: 700;
    background: transparent;
    color: var(--columbia-blue);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.tab-btn:hover {
    background: rgba(80, 125, 188, 0.2);
}

.tab-btn.active {
    background: linear-gradient(135deg, var(--glaucous) 0%, var(--powder-blue) 100%);
    color: var(--rich-black);
}

/* Tab Content */
.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Upload Area */
.upload-area {
    background: rgba(80, 125, 188, 0.1);
    border: 3px dashed var(--glaucous);
    border-radius: 20px;
    padding: 60px 40px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 30px;
}

.upload-area:hover {
    background: rgba(80, 125, 188, 0.15);
    border-color: var(--powder-blue);
    transform: translateY(-2px);
}

.upload-area.dragover {
    background: rgba(80, 125, 188, 0.2);
    border-color: var(--powder-blue);
    transform: scale(1.02);
}

.upload-icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.upload-area h3 {
    color: var(--powder-blue);
    font-size: 1.3rem;
    margin-bottom: 10px;
}

.upload-area p {
    color: var(--columbia-blue);
    opacity: 0.8;
    margin-bottom: 20px;
}

.upload-btn {
    padding: 12px 30px;
    font-size: 1rem;
    font-family: 'Play', sans-serif;
    font-weight: 700;
    background: linear-gradient(135deg, var(--glaucous) 0%, var(--powder-blue) 100%);
    color: var(--rich-black);
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(80, 125, 188, 0.4);
}

/* File Info */
.file-info {
    background: rgba(80, 125, 188, 0.1);
    border: 1px solid rgba(80, 125, 188, 0.3);
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 30px;
}

.info-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.file-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--powder-blue);
}

.remove-btn {
    background: rgba(239, 68, 68, 0.2);
    color: var(--error-red);
    border: none;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    font-size: 1.2rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.remove-btn:hover {
    background: var(--error-red);
    color: white;
}

.info-details {
    color: var(--columbia-blue);
    margin-bottom: 20px;
    opacity: 0.8;
}

/* Progress Bar */
.progress-container {
    margin: 20px 0;
}

.progress-bar {
    width: 0%;
    height: 8px;
    background: linear-gradient(90deg, var(--glaucous) 0%, var(--powder-blue) 100%);
    border-radius: 10px;
    transition: width 0.3s ease;
    margin-bottom: 10px;
}

.progress-text {
    color: var(--columbia-blue);
    font-size: 0.9rem;
    text-align: center;
}

/* Convert Button */
.convert-btn {
    width: 100%;
    padding: 15px;
    font-size: 1.1rem;
    font-family: 'Play', sans-serif;
    font-weight: 700;
    background: linear-gradient(135deg, var(--success-green) 0%, #059669 100%);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.convert-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(16, 185, 129, 0.4);
}

.convert-btn:disabled {
    background: rgba(80, 125, 188, 0.3);
    cursor: not-allowed;
    transform: none;
}

/* Features */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 40px 0;
}

.feature-card {
    background: rgba(80, 125, 188, 0.1);
    border: 1px solid rgba(80, 125, 188, 0.2);
    border-radius: 15px;
    padding: 30px;
    text-align: center;
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--powder-blue);
    box-shadow: 0 10px 30px rgba(80, 125, 188, 0.2);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.feature-card h3 {
    color: var(--powder-blue);
    font-size: 1.2rem;
    margin-bottom: 10px;
}

.feature-card p {
    color: var(--columbia-blue);
    opacity: 0.8;
    font-size: 0.95rem;
}

/* Info Box */
.info-box {
    background: rgba(80, 125, 188, 0.1);
    border-left: 4px solid var(--glaucous);
    border-radius: 10px;
    padding: 25px;
    margin: 30px 0;
}

.info-box h3 {
    color: var(--powder-blue);
    margin-bottom: 15px;
}

.info-box ol {
    color: var(--columbia-blue);
    padding-left: 20px;
}

.info-box li {
    margin-bottom: 10px;
}

.info-box strong {
    color: var(--powder-blue);
}

/* Footer */
.footer {
    text-align: center;
    margin-top: 60px;
    padding: 40px 20px;
    border-top: 1px solid rgba(80, 125, 188, 0.2);
    color: var(--columbia-blue);
    font-size: 0.95rem;
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(4, 8, 15, 0.95);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid rgba(80, 125, 188, 0.2);
    border-top: 4px solid var(--powder-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

    100% {
        transform: rotate(360deg);
    }
}

.loading-overlay p {
    color: var(--powder-blue);
    margin-top: 20px;
    font-size: 1.1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .upload-area {
        padding: 40px 20px;
    }

    .upload-icon {
        font-size: 3rem;
    }

    .features {
        grid-template-columns: 1fr;
    }

    .converter-tabs {
        flex-direction: column;
    }
}