:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: rgba(18, 18, 26, 0.8);
    --accent: #00d4aa;
    --accent-dim: rgba(0, 212, 170, 0.1);
    --text-primary: #e0e0e0;
    --text-secondary: #a0a0b0;
    --border: #2a2a3e;
    --success: #2ecc71;
    --warning: #f39c12;
    --error: #e74c3c;
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

/* Navigation */
.nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent);
    text-decoration: none;
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    width: 90px;
}

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-menu a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
    padding: 0.5rem 1rem;
    border-radius: 8px;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--accent);
    background: var(--accent-dim);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 30px;
    height: 21px;
    cursor: pointer;
    z-index: 1001;
}

.menu-toggle span {
    display: block;
    width: 100%;
    height: 3px;
    background: var(--accent);
    border-radius: 3px;
    transition: all 0.3s;
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    .nav-menu {
        position: fixed;
        top: 0;
        left: -100%;
        width: 100%;
        height: 100vh;
        background: var(--bg-primary);
        flex-direction: column;
        justify-content: center;
        transition: left 0.3s;
        z-index: 1000;
    }
    .nav-menu.active {
        left: 0;
    }
    .nav-menu a {
        font-size: 1.5rem;
    }
}

/* Header */
.app-header {
    text-align: center;
    margin-bottom: 2rem;
}

.app-header h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--accent), #00a8ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.security-badges {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.badge {
    background: var(--accent-dim);
    color: var(--accent);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

/* Cards */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.card h2 {
    margin-bottom: 1rem;
    color: var(--accent);
}

/* Upload Zone */
.upload-zone {
    border: 2px dashed var(--border);
    border-radius: 12px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    margin-bottom: 1rem;
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: var(--accent);
    background: var(--accent-dim);
}

.upload-icon {
    width: 48px;
    height: 48px;
    color: var(--accent);
    margin-bottom: 1rem;
}

.upload-text {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.upload-hint {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Options */
.upload-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1rem;
}

.option-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.option-group label {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.option-group select {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 0.5rem;
    border-radius: 6px;
    font-size: 0.95rem;
}

@media (max-width: 480px) {
    .upload-options {
        grid-template-columns: 1fr;
    }
}

/* Progress */
.progress-container {
    margin-top: 1rem;
}

.progress-bar {
    height: 8px;
    background: var(--bg-secondary);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent), #00ff88);
    border-radius: 4px;
    transition: width 0.3s;
    width: 0%;
}

.progress-text {
    text-align: center;
    margin-top: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Result */
.result-container {
    text-align: center;
    padding: 1.5rem;
}

.success-icon {
    width: 60px;
    height: 60px;
    background: var(--success);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin: 0 auto 1rem;
}

.share-link-box {
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: 8px;
    margin: 1rem 0;
}

.share-link-box label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.link-input-group {
    display: flex;
    gap: 0.5rem;
}

.link-input-group input {
    flex: 1;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 6px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
}

.share-details {
    text-align: left;
    margin-top: 1rem;
}

.share-details p {
    margin-bottom: 0.5rem;
}

.warning {
    color: var(--warning);
    font-size: 0.9rem;
    margin-top: 1rem;
}

/* Buttons */
.btn {
    background: var(--accent);
    color: var(--bg-primary);
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.3);
}

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

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

/* Download Section */
.file-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--bg-secondary);
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.file-icon {
    width: 48px;
    height: 48px;
    color: var(--accent);
}

.filename {
    font-weight: 600;
    font-size: 1.1rem;
}

.file-meta {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.download-note {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: 1rem;
}

/* Error */
.error-message {
    background: rgba(231, 76, 60, 0.1);
    border: 1px solid var(--error);
    color: var(--error);
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
}

/* About Section */
.about-section h2 {
    margin-bottom: 1.5rem;
}

.steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-bottom: 2rem;
}

@media (max-width: 600px) {
    .steps {
        grid-template-columns: 1fr;
    }
}

.step {
    text-align: center;
}

.step-number {
    width: 40px;
    height: 40px;
    background: var(--accent);
    color: var(--bg-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    margin: 0 auto 0.75rem;
}

.step h3 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

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

.security-info {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: 8px;
}

.security-info h3 {
    margin-bottom: 1rem;
    color: var(--accent);
}

.security-info ul {
    list-style: none;
}

.security-info li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.security-info li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success);
    font-weight: bold;
}

/* Footer */
.app-footer {
    text-align: center;
    padding: 2rem 0;
}

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

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

/* Utilities */
.hidden {
    display: none !important;
}