:root {
    /* HeyTec Branding Farben */
    --heytec-blue: #00247D;
    --heytec-blue-dark: #001a5c;
    --heytec-blue-light: #003399;
    
    /* Anthrazit Design */
    --anthrazit-dark: #2b2d31;
    --anthrazit-medium: #3a3d42;
    --anthrazit-light: #4a4d52;
    --anthrazit-lighter: #5a5d62;
    
    /* Akzentfarben */
    --accent-blue: #0066cc;
    --accent-green: #00cc66;
    --accent-red: #cc3333;
    --accent-orange: #ff9933;
    
    /* Graustufen */
    --background: #1e1f22;
    --card-background: #2b2d31;
    --card-hover: #313338;
    --text-primary: #f2f3f5;
    --text-secondary: #b5bac1;
    --text-muted: #80848e;
    --border-color: #3a3d42;
    
    /* Schatten */
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-strong: 0 8px 32px rgba(0, 0, 0, 0.5);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* Header mit HeyTec Branding */
header {
    background: linear-gradient(135deg, var(--heytec-blue-dark), var(--heytec-blue));
    color: white;
    border-radius: 16px;
    margin-bottom: 30px;
    box-shadow: var(--shadow-strong);
    overflow: hidden;
    position: relative;
}

.header-content {
    padding: 40px;
    position: relative;
    z-index: 2;
}

.header-branding {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 30px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.heytec-logo {
    height: 80px;
    width: auto;
    filter: brightness(0) invert(1);
}

.header-divider {
    width: 2px;
    height: 60px;
    background: rgba(255, 255, 255, 0.3);
}

.header-title {
    text-align: center;
}

.header-title h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.3);
}

.header-title .subtitle {
    font-size: 1.1rem;
    opacity: 0.95;
    font-weight: 400;
}

.heytec-badge {
    display: inline-block;
    background: rgba(255, 255, 255, 0.15);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    margin-top: 10px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

/* Decorative background pattern */
header::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 100%;
    height: 100%;
    background: 
        linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.03) 30%, rgba(255, 255, 255, 0.03) 70%, transparent 70%),
        linear-gradient(-45deg, transparent 30%, rgba(255, 255, 255, 0.03) 30%, rgba(255, 255, 255, 0.03) 70%, transparent 70%);
    background-size: 60px 60px;
    opacity: 0.5;
    z-index: 1;
}

.main-content {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.card {
    background: var(--card-background);
    border-radius: 16px;
    padding: 30px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.card:hover {
    box-shadow: var(--shadow-hover);
    background: var(--card-hover);
    transform: translateY(-2px);
}

.card h2 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 12px;
    padding-bottom: 15px;
    border-bottom: 2px solid var(--border-color);
}

.card h2 i {
    color: var(--heytec-blue-light);
    font-size: 1.3rem;
}

.info-text {
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-size: 0.95rem;
    padding: 12px;
    background: rgba(0, 102, 204, 0.1);
    border-left: 3px solid var(--heytec-blue-light);
    border-radius: 4px;
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 25px;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.required {
    color: var(--accent-red);
}

.form-group input,
.form-group select {
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background: var(--anthrazit-medium);
    color: var(--text-primary);
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--heytec-blue-light);
    background: var(--anthrazit-light);
    box-shadow: 0 0 0 3px rgba(0, 51, 153, 0.1);
}

.form-group small {
    margin-top: 5px;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.button-group {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
    text-decoration: none;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--heytec-blue-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 36, 125, 0.4);
}

.btn-secondary {
    background: var(--anthrazit-lighter);
    color: white;
}

.btn-secondary:hover:not(:disabled) {
    background: var(--anthrazit-light);
    transform: translateY(-2px);
}

.btn-success {
    background: var(--accent-green);
    color: white;
}

.btn-success:hover:not(:disabled) {
    background: #00b359;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 204, 102, 0.4);
}

.btn-large {
    width: 100%;
    padding: 16px 24px;
    font-size: 1.1rem;
    margin-top: 20px;
}

.btn-icon {
    background: transparent;
    border: none;
    color: var(--accent-red);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: background 0.3s ease;
}

.btn-icon:hover {
    background: rgba(204, 51, 51, 0.15);
}

.upload-area {
    border: 3px dashed var(--border-color);
    border-radius: 12px;
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 20px;
    background: var(--anthrazit-medium);
}

.upload-area:hover {
    border-color: var(--heytec-blue-light);
    background: var(--anthrazit-light);
}

.upload-area.drag-over {
    border-color: var(--heytec-blue);
    background: rgba(0, 36, 125, 0.1);
}

.upload-area i {
    font-size: 3rem;
    color: var(--heytec-blue-light);
    margin-bottom: 15px;
}

.upload-area p {
    font-size: 1.1rem;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.upload-area small {
    color: var(--text-secondary);
}

.file-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: var(--anthrazit-medium);
    border-radius: 8px;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
}

.file-details {
    display: flex;
    align-items: center;
    gap: 15px;
}

.file-details i {
    font-size: 2rem;
    color: var(--heytec-blue-light);
}

.file-details strong {
    display: block;
    color: var(--text-primary);
}

.file-details p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin: 0;
}

.validation-result {
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.validation-result.success {
    background: rgba(0, 204, 102, 0.15);
    border: 1px solid var(--accent-green);
    color: var(--accent-green);
}

.validation-result.error {
    background: rgba(204, 51, 51, 0.15);
    border: 1px solid var(--accent-red);
    color: var(--accent-red);
}

.code-block {
    background: var(--anthrazit-dark);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 20px;
    margin: 20px 0;
    overflow-x: auto;
}

.code-block pre {
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    margin: 0;
    color: var(--text-secondary);
}

.info-box {
    background: rgba(0, 36, 125, 0.1);
    border-left: 4px solid var(--heytec-blue);
    padding: 20px;
    border-radius: 8px;
    margin-top: 20px;
}

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

.info-box ul {
    list-style: none;
    padding: 0;
}

.info-box ul li {
    padding: 8px 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.info-box ul li:last-child {
    border-bottom: none;
}

.info-box ul li strong {
    color: var(--heytec-blue-light);
    min-width: 150px;
    display: inline-block;
}

.toast {
    position: fixed;
    bottom: 30px;
    right: 30px;
    padding: 16px 24px;
    background: var(--anthrazit-medium);
    color: white;
    border-radius: 8px;
    box-shadow: var(--shadow-strong);
    transform: translateX(400px);
    transition: transform 0.3s ease;
    z-index: 1000;
    max-width: 400px;
    border: 1px solid var(--border-color);
}

.toast.show {
    transform: translateX(0);
}

.toast.success {
    background: var(--accent-green);
    border-color: var(--accent-green);
}

.toast.error {
    background: var(--accent-red);
    border-color: var(--accent-red);
}

/* Footer mit HeyTec Branding */
footer {
    text-align: center;
    padding: 40px 20px;
    margin-top: 60px;
    border-top: 2px solid var(--border-color);
    background: var(--card-background);
    border-radius: 16px;
}

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

.footer-logo {
    height: 50px;
    width: auto;
    opacity: 0.7;
    transition: opacity 0.3s ease;
}

.footer-logo:hover {
    opacity: 1;
}

.footer-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.footer-text strong {
    color: var(--heytec-blue-light);
    font-weight: 600;
}

.footer-links {
    display: flex;
    gap: 20px;
    margin-top: 10px;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    transition: color 0.3s ease;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--heytec-blue-light);
}

@media (max-width: 768px) {
    .header-branding {
        flex-direction: column;
        gap: 20px;
    }

    .header-divider {
        width: 60px;
        height: 2px;
    }

    .heytec-logo {
        height: 60px;
    }

    .header-title h1 {
        font-size: 1.8rem;
    }

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

    .button-group {
        flex-direction: column;
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .toast {
        right: 20px;
        left: 20px;
        max-width: none;
    }

    .footer-links {
        flex-direction: column;
        gap: 10px;
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 12px;
}

::-webkit-scrollbar-track {
    background: var(--anthrazit-dark);
}

::-webkit-scrollbar-thumb {
    background: var(--anthrazit-lighter);
    border-radius: 6px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--heytec-blue-light);
}

/* Selection Styling */
::selection {
    background: var(--heytec-blue);
    color: white;
}