:root {
    --primary: #1a56db;
    --primary-dark: #1e40af;
    --secondary: #4b5563;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;
    --bg: #f8fafc;
    --card: #ffffff;
    --text: #1e293b;
    --border: #e2e8f0;
    --header-bg: #7496df;
    --footer-bg: #1e40af;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', system-ui, sans-serif;
}

body {
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: var(--header-bg);
    color: white;
    padding: 20px 0;
}

.header-content {
    display: flex;
    align-items: center;
    gap: 20px;
}

.logo {
    height: 100px;
    width: auto;
}

.main-nav {
    background: var(--primary-dark);
    padding: 10px 0;
}

.main-nav ul {
    display: flex;
    list-style: none;
    gap: 30px;
}

.main-nav a {
    color: white;
    text-decoration: none;
    font-weight: 500;
}

.main-nav a:hover {
    text-decoration: underline;
}

main {
    flex: 1;
    padding: 40px 0;
}

h1, h2, h3 {
    margin-bottom: 20px;
    color: var(--primary);
}

.intro {
    margin-bottom: 30px;
    text-align: center;
}

.form-section {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    margin-bottom: 25px;
}

.form-section h3 {
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border);
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

.required {
    color: var(--error);
    font-weight: bold;
}

input, textarea, select {
    width: 100%;
    padding: 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 16px;
    transition: border 0.3s;
}

input:focus, textarea:focus, select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(26, 86, 219, 0.1);
}

textarea {
    min-height: 120px;
    resize: vertical;
}

.file-upload-label {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.3s;
    text-align: center;
}

.file-upload-label:hover {
    background: var(--primary-dark);
}

.file-upload-label input {
    display: none;
}

.file-feedback {
    margin-top: 10px;
    padding: 10px;
    border-radius: 6px;
    background: #f1f5f9;
}

.file-uploaded {
    background: #dcfce7;
    color: var(--success);
}

.btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: background 0.3s;
}

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

.btn.secondary {
    background: var(--secondary);
    margin-top: 15px;
}

.btn.secondary:hover {
    background: #374151;
}

#qrResult {
    text-align: center;
    margin-top: 30px;
}

#qrcode {
    display: inline-block;
    padding: 20px;
    background: white;
    border-radius: 12px;
    margin: 20px auto;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    position: relative;
}

.hidden {
    display: none !important;
}

#deviceInfo {
    background: #f1f5f9;
    padding: 25px;
    border-radius: 12px;
    margin-bottom: 30px;
}

#deviceInfo p {
    margin: 12px 0;
    font-size: 17px;
}

#message {
    padding: 20px;
    margin-top: 25px;
    border-radius: 10px;
    text-align: center;
    font-weight: 500;
}

.success {
    background-color: #dcfce7;
    color: var(--success);
    border: 1px solid #bbf7d0;
}

.error {
    background-color: #fee2e2;
    color: var(--error);
    border: 1px solid #fecaca;
}

footer {
    background: var(--footer-bg);
    color: white;
    text-align: center;
    padding: 25px 0;
    margin-top: auto;
}

footer a {
    color: white;
    text-decoration: none;
}

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

/* Responsive Design */
@media (max-width: 900px) {
    .container {
        padding: 15px;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
        gap: 10px;
    }
    
    .main-nav ul {
        flex-direction: column;
        gap: 10px;
    }
}

@media (max-width: 600px) {
    .form-section {
        padding: 15px;
    }
    
    input, textarea, select {
        padding: 12px;
    }
    
    .btn {
        padding: 12px 20px;
    }
    
    #deviceInfo {
        padding: 15px;
    }
    
    #deviceInfo p {
        font-size: 16px;
    }
}

@media (max-width: 320px) {
    body {
        padding: 5px;
    }
    
    .container {
        padding: 10px;
    }
    
    h1 {
        font-size: 22px;
    }
    
    h2 {
        font-size: 20px;
    }
    
    h3 {
        font-size: 18px;
    }
    
    .logo {
        height: 40px;
    }
}