/* ===== CSS VARIABLES & RESET ===== */
:root {
    --primary: #494eea;
    --primary-hover: #3a3fc7;
    --success: #2ecc71;
    --success-hover: #27ae60;
    --danger: #e74c3c;
    --bg-dark: #1e3c72;
    --bg-light: #2a5298;
    --text-dark: #2c3e50;
    --text-muted: #7f8c8d;
    --border-radius: clamp(8px, 2vw, 12px);
    --spacing-xs: clamp(4px, 1vw, 8px);
    --spacing-sm: clamp(8px, 2vw, 16px);
    --spacing-md: clamp(16px, 3vw, 24px);
    --spacing-lg: clamp(24px, 4vw, 40px);
    --touch-target: 44px;
}

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

html {
    font-size: clamp(14px, 2vw, 16px);
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--bg-light) 100%);
    min-height: 100vh;
    min-height: 100dvh; /* Dynamic viewport height for mobile */
    padding: var(--spacing-md);
    line-height: 1.6;
    /* Safe area for notched devices */
    padding-top: max(var(--spacing-md), env(safe-area-inset-top));
    padding-bottom: max(var(--spacing-md), env(safe-area-inset-bottom));
    padding-left: max(var(--spacing-md), env(safe-area-inset-left));
    padding-right: max(var(--spacing-md), env(safe-area-inset-right));
}

/* ===== LAYOUT ===== */
.wrapper {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 380px), 1fr));
    gap: var(--spacing-lg);
    max-width: 1200px;
    margin: 0 auto;
    align-items: start;
}

.container {
    background: #fff;
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    width: 100%;
    max-width: 450px;
    margin: 0 auto;
}

/* ===== TYPOGRAPHY ===== */
.container h3 {
    color: var(--text-dark);
    margin-bottom: var(--spacing-md);
    font-size: clamp(1.1rem, 4vw, 1.3rem);
    text-align: center;
    font-weight: 700;
}

.container p {
    font-weight: 600;
    font-size: clamp(0.9rem, 3vw, 1rem);
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

/* ===== FORM ELEMENTS ===== */
.container input[type="text"] {
    width: 100%;
    min-height: var(--touch-target);
    border: 2px solid #3498db;
    outline: 0;
    padding: var(--spacing-sm) var(--spacing-md);
    margin: var(--spacing-sm) 0 var(--spacing-md);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: all 0.3s ease;
    -webkit-appearance: none;
    appearance: none;
}

.container input[type="text"]:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(73, 78, 234, 0.1);
}

/* ===== BUTTONS ===== */
.btn-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

button {
    width: 100%;
    min-height: var(--touch-target);
    border: 0;
    outline: 0;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    font-size: clamp(0.9rem, 3vw, 1rem);
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

button:active {
    transform: scale(0.98);
}

.btn-primary {
    background: var(--primary);
    color: #fff;
    box-shadow: 0 4px 15px rgba(73, 78, 234, 0.3);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(73, 78, 234, 0.4);
}

.btn-success {
    background: var(--success);
    color: #fff;
    box-shadow: 0 4px 15px rgba(46, 204, 113, 0.3);
}

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

/* ===== QR IMAGE BOX ===== */
#imgBox {
    width: min(200px, 60vw);
    border-radius: var(--border-radius);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.5s ease;
    margin: 0 auto;
}

#imgBox img {
    width: 100%;
    height: auto;
    padding: var(--spacing-sm);
    display: block;
}

#imgBox.show-img {
    max-height: 300px;
    margin: var(--spacing-md) auto;
    border: 2px dashed var(--primary);
    background: #f8f9fa;
}

/* ===== TABS ===== */
.tabs {
    display: flex;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.tab-btn {
    flex: 1;
    background: #ecf0f1;
    color: var(--text-dark);
    font-size: clamp(0.85rem, 3vw, 0.95rem);
}

.tab-btn.active {
    background: var(--primary);
    color: #fff;
}

/* ===== TAB CONTENT ===== */
.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ===== SCANNER ===== */
#reader {
    width: 100% !important;
    border-radius: var(--border-radius);
    overflow: hidden;
    min-height: 250px;
}

#reader video {
    border-radius: var(--border-radius);
    width: 100% !important;
    height: auto !important;
}

.small-text {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-top: var(--spacing-sm);
    font-weight: 500;
}

/* ===== UPLOAD AREA ===== */
.upload-area {
    border: 3px dashed #3498db;
    border-radius: var(--border-radius);
    padding: clamp(30px, 8vw, 50px) var(--spacing-md);
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: #f8f9fa;
    min-height: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.upload-area:hover {
    border-color: var(--primary);
    background: #e8f4f8;
}

.upload-area:active {
    transform: scale(0.98);
}

.upload-icon {
    font-size: clamp(2rem, 8vw, 3rem);
    display: block;
}

.upload-area p {
    margin: 0;
    font-size: clamp(1rem, 4vw, 1.2rem);
    color: var(--text-dark);
}

.file-types {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

/* ===== RESULT BOX ===== */
.result-box {
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: #f8f9fa;
    border-radius: var(--border-radius);
    border-left: 4px solid var(--success);
    animation: slideIn 0.3s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-label {
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: var(--spacing-sm);
    font-size: 0.9rem;
}

.result-box textarea {
    width: 100%;
    min-height: 80px;
    padding: var(--spacing-sm);
    border: 1px solid #ddd;
    border-radius: 8px;
    resize: vertical;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
    -webkit-appearance: none;
}

.action-btns {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-sm);
}

.btn-copy {
    background: var(--success);
    color: #fff;
}

.btn-copy:hover {
    background: var(--success-hover);
}

.btn-link {
    background: var(--danger);
    color: #fff;
}

.btn-link:hover {
    background: #c0392b;
}

/* ===== ERROR ANIMATION ===== */
.error {
    animation: shake 0.1s linear 10;
    border-color: var(--danger) !important;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

/* ===== UTILITY ===== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* ===== MEDIA QUERIES ===== */

/* Small phones (up to 360px) */
@media (max-width: 360px) {
    :root {
        --spacing-md: 12px;
        --spacing-lg: 16px;
    }
    
    .container {
        padding: var(--spacing-md);
    }
    
    .upload-area {
        padding: 20px 12px;
    }
    
    #reader {
        min-height: 200px;
    }
}

/* Large phones and small tablets (361px - 768px) */
@media (min-width: 361px) and (max-width: 768px) {
    .wrapper {
        gap: var(--spacing-md);
    }
    
    .action-btns {
        grid-template-columns: 1fr;
    }
}

/* Tablets (769px - 1024px) */
@media (min-width: 769px) and (max-width: 1024px) {
    .wrapper {
        grid-template-columns: repeat(2, 1fr);
        max-width: 900px;
    }
    
    .container {
        max-width: none;
    }
}

/* Desktop (1025px and up) */
@media (min-width: 1025px) {
    .wrapper {
        grid-template-columns: repeat(2, 1fr);
        max-width: 1000px;
    }
    
    .btn-group {
        flex-direction: row;
    }
    
    .btn-group button {
        flex: 1;
    }
}

/* Landscape mode on mobile */
@media (max-height: 500px) and (orientation: landscape) {
    body {
        padding: 10px;
    }
    
    .wrapper {
        grid-template-columns: 1fr 1fr;
        gap: 15px;
    }
    
    .container {
        padding: 15px;
    }
    
    #reader {
        min-height: 150px;
    }
    
    .upload-area {
        min-height: 150px;
        padding: 20px;
    }
}

/* High DPI / Retina displays */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .container {
        box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
    }
}

/* Dark mode support (optional enhancement) */
@media (prefers-color-scheme: dark) {
    body {
        background: linear-gradient(135deg, #0f2027 0%, #203a43 50%, #2c5364 100%);
    }
    
    .container {
        background: #1a1a2e;
        color: #eee;
    }
    
    .container h3, .container p {
        color: #fff;
    }
    
    .upload-area {
        background: #16213e;
        border-color: #0f3460;
    }
    
    .upload-area p {
        color: #eee;
    }
    
    .tab-btn {
        background: #16213e;
        color: #eee;
    }
    
    .result-box {
        background: #16213e;
    }
    
    .result-box textarea {
        background: #0f3460;
        color: #fff;
        border-color: #1a1a2e;
    }
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Print styles */
@media print {
    body {
        background: white;
    }
    
    .wrapper {
        display: block;
    }
    
    .container {
        box-shadow: none;
        page-break-inside: avoid;
    }
    
    button, .tabs, #reader, .upload-area {
        display: none !important;
    }
    
    #imgBox {
        max-height: none !important;
        border: 1px solid #000 !important;
    }
}