:root {
    --bg-color: #0d1117;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --accent-color: #58a6ff;
    --accent-hover: #3182ce;
    --card-bg: rgba(22, 27, 34, 0.6);
    --card-border: rgba(48, 54, 61, 0.5);
    --glass-blur: blur(12px);
    --success-color: #3fb950;
    --error-color: #f85149;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    overflow-x: hidden;
}

/* Background animated blobs */
.background-elements {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
}

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

.blob-1 {
    top: -10%;
    left: -10%;
    width: 50vw;
    height: 50vw;
    background: radial-gradient(circle, rgba(88,166,255,0.4) 0%, rgba(13,17,23,0) 70%);
}

.blob-2 {
    bottom: -10%;
    right: -10%;
    width: 60vw;
    height: 60vw;
    background: radial-gradient(circle, rgba(163,113,247,0.3) 0%, rgba(13,17,23,0) 70%);
    animation-delay: -10s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(10%, 10%) scale(1.1); }
}

/* Main Container */
.container {
    max-width: 800px;
    width: 90%;
    margin: 4rem auto;
    display: flex;
    flex-direction: column;
    gap: 3rem;
    z-index: 1;
}

/* Header */
.header {
    text-align: center;
}

.gradient-text {
    font-size: 3.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, #58a6ff 0%, #a371f7 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
    letter-spacing: -1px;
}

.header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    max-width: 500px;
    margin: 0 auto;
}

/* Upload Section */
.upload-section {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    padding: 3rem;
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    display: flex;
    flex-direction: column;
    gap: 2rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.upload-section:hover {
    transform: translateY(-5px);
    box-shadow: 0 35px 60px -15px rgba(0, 0, 0, 0.6);
}

.drop-zone {
    border: 2px dashed var(--card-border);
    border-radius: 16px;
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    position: relative;
    overflow: hidden;
}

.drop-zone.dragover {
    border-color: var(--accent-color);
    background: rgba(88, 166, 255, 0.05);
}

.icon-container {
    color: var(--text-secondary);
    transition: color 0.3s ease, transform 0.3s ease;
}

.drop-zone:hover .icon-container, .drop-zone.dragover .icon-container {
    color: var(--accent-color);
    transform: scale(1.1);
}

.drop-zone h3 {
    font-size: 1.25rem;
    font-weight: 600;
}

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

.browse-link {
    color: var(--accent-color);
    font-weight: 600;
    text-decoration: underline;
}

.file-name-display {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--success-color);
    font-weight: 600;
    word-break: break-all;
}

/* Button */
.btn {
    appearance: none;
    background: var(--text-primary);
    color: var(--bg-color);
    border: none;
    border-radius: 12px;
    padding: 1rem 2rem;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
}

.btn:disabled {
    background: var(--card-border);
    color: var(--text-secondary);
    cursor: not-allowed;
    transform: none !important;
}

.btn:not(:disabled):hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px -10px rgba(230, 237, 243, 0.5);
}

.btn:not(:disabled):active {
    transform: translateY(0);
}

/* Spinner */
.spinner {
    display: none;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(13, 17, 23, 0.3);
    border-radius: 50%;
    border-top-color: var(--bg-color);
    animation: spin 1s ease-in-out infinite;
}

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

.btn.loading .btn-text {
    display: none;
}

.btn.loading .spinner {
    display: block;
}

.error-message {
    color: var(--error-color);
    text-align: center;
    font-size: 0.9rem;
    min-height: 1.2rem;
}

/* Features */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 2rem;
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.feature-card h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Responsive */
@media (max-width: 600px) {
    .gradient-text {
        font-size: 2.5rem;
    }
    .upload-section {
        padding: 2rem;
    }
}