/**
 * ระบบสอบย้อนกลับผักอุดร - Responsive Design CSS
 * =================================================
 * Mobile-first responsive design optimized for Thai users
 * Tested on: iPhone 12/13/14, Samsung Galaxy, iPad
 */

/* ========================================
   CSS Variables for Consistency
   ======================================== */

:root {
    /* Touch Targets */
    --touch-target-min: 44px;
    --touch-target-comfortable: 48px;
    --touch-target-large: 56px;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    
    /* Font Sizes - Mobile First */
    --font-xs: 0.75rem;
    --font-sm: 0.875rem;
    --font-base: 1rem;
    --font-lg: 1.125rem;
    --font-xl: 1.25rem;
    --font-2xl: 1.5rem;
    --font-3xl: 1.875rem;
    --font-4xl: 2.25rem;
    
    /* Colors */
    --primary: #198754;
    --primary-dark: #157347;
    --primary-light: #20c997;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-light: #ffffff;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15);
    
    /* Border Radius */
    --rounded-sm: 0.25rem;
    --rounded-md: 0.375rem;
    --rounded-lg: 0.5rem;
    --rounded-xl: 0.75rem;
    --rounded-2xl: 1rem;
    --rounded-3xl: 1.5rem;
    --rounded-full: 9999px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* ========================================
   Base Mobile-First Styles
   ======================================== */

/* Reset and base styles */
* {
    -webkit-tap-highlight-color: transparent;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

/* Allow text selection where needed */
input, textarea, [contenteditable="true"], .selectable-text {
    -webkit-user-select: auto;
    -moz-user-select: auto;
    -ms-user-select: auto;
    user-select: auto;
}

html {
    font-size: 16px; /* Prevent zoom on iOS */
    -webkit-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
    scroll-behavior: smooth;
}

body {
    font-family: 'Sarabun', 'Noto Sans Thai', 'Helvetica Neue', Arial, sans-serif;
    font-size: var(--font-base);
    line-height: 1.6;
    color: var(--text-primary);
    overflow-x: hidden;
    background: #ffffff;
}

/* ========================================
   Touch-Friendly Buttons & Interactions
   ======================================== */

/* Base button styles */
.btn {
    min-height: var(--touch-target-min);
    min-width: var(--touch-target-min);
    padding: 0.75rem 1.5rem;
    border-radius: var(--rounded-xl);
    font-weight: 600;
    font-size: var(--font-base);
    transition: all var(--transition-base);
    touch-action: manipulation;
    user-select: none;
    position: relative;
    overflow: hidden;
    border: none;
    cursor: pointer;
}

/* Touch feedback */
.btn:active {
    transform: scale(0.98);
    transition: transform 0.1s ease;
}

/* Large touch targets for mobile */
.btn-touch-large {
    min-height: var(--touch-target-large);
    padding: 1rem 2rem;
    font-size: var(--font-lg);
}

/* Icon buttons */
.btn-icon {
    width: var(--touch-target-min);
    height: var(--touch-target-min);
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--rounded-full);
}

.btn-icon-large {
    width: var(--touch-target-large);
    height: var(--touch-target-large);
}

/* ========================================
   Mobile Hero Carousel Optimizations
   ======================================== */

.hero-section {
    min-height: 100vh;
    min-height: 100dvh; /* Dynamic viewport height for mobile */
    position: relative;
    overflow: hidden;
}

/* Mobile carousel optimization */
.hero-carousel-mobile {
    height: 100vh;
    height: 100dvh;
    touch-action: pan-x pan-y;
}

.hero-slide {
    height: 100vh;
    height: 100dvh;
    background-attachment: scroll; /* Better performance on mobile */
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    padding: var(--space-md);
}

/* Mobile hero content */
.hero-content {
    text-align: center;
    width: 100%;
    padding: var(--space-lg);
}

.hero-content h1 {
    font-size: var(--font-2xl);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--space-lg);
    text-shadow: 2px 2px 8px rgba(0, 0, 0, 0.5);
}

.hero-content p {
    font-size: var(--font-base);
    line-height: 1.5;
    margin-bottom: var(--space-xl);
    text-shadow: 1px 1px 4px rgba(0, 0, 0, 0.5);
}

/* Mobile action buttons */
.hero-action {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    width: 100%;
    max-width: 320px;
    margin: 0 auto;
}

.hero-action .btn {
    width: 100%;
    min-height: var(--touch-target-large);
    font-size: var(--font-lg);
    font-weight: 600;
    border-radius: var(--rounded-2xl);
    padding: 1rem 2rem;
}

/* Touch-optimized carousel indicators */
.carousel-indicators {
    bottom: 2rem;
    gap: var(--space-sm);
}

.carousel-indicators button {
    width: 12px;
    height: 12px;
    min-width: var(--touch-target-min);
    min-height: var(--touch-target-min);
    border-radius: var(--rounded-full);
    margin: 0 var(--space-xs);
    background-color: rgba(255, 255, 255, 0.5);
    border: none;
    transition: all var(--transition-base);
    position: relative;
}

.carousel-indicators button::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: var(--touch-target-min);
    height: var(--touch-target-min);
    border-radius: var(--rounded-full);
}

.carousel-indicators button.active {
    background-color: rgba(255, 255, 255, 0.9);
    transform: scale(1.2);
}

/* ========================================
   QR Scanner Mobile Optimizations
   ======================================== */

/* Fullscreen scanner */
.qr-scanner-fullscreen {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 9999;
    background: #000;
    display: flex;
    flex-direction: column;
}

.qr-scanner-header {
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: var(--space-md);
    padding-top: calc(var(--space-md) + env(safe-area-inset-top));
    display: flex;
    justify-content: between;
    align-items: center;
    position: relative;
    z-index: 10;
}

.qr-scanner-title {
    font-size: var(--font-lg);
    font-weight: 600;
    flex: 1;
    text-align: center;
}

.qr-scanner-close {
    position: absolute;
    right: var(--space-md);
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    width: var(--touch-target-min);
    height: var(--touch-target-min);
    border-radius: var(--rounded-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-lg);
}

/* Camera view */
.qr-camera-container {
    flex: 1;
    position: relative;
    overflow: hidden;
}

.qr-video {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Scanner overlay */
.qr-scanner-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.3);
}

.qr-scanner-box {
    width: 280px;
    height: 280px;
    border: 3px solid var(--primary-light);
    border-radius: var(--rounded-2xl);
    position: relative;
    background: transparent;
    box-shadow: 
        0 0 0 9999px rgba(0, 0, 0, 0.5),
        inset 0 0 0 3px rgba(255, 255, 255, 0.2);
}

/* Scanner corners */
.qr-scanner-corners {
    position: absolute;
    top: -3px;
    left: -3px;
    right: -3px;
    bottom: -3px;
}

.qr-corner {
    position: absolute;
    width: 30px;
    height: 30px;
    border: 4px solid var(--primary-light);
}

.qr-corner-tl {
    top: 0;
    left: 0;
    border-right: none;
    border-bottom: none;
    border-top-left-radius: var(--rounded-lg);
}

.qr-corner-tr {
    top: 0;
    right: 0;
    border-left: none;
    border-bottom: none;
    border-top-right-radius: var(--rounded-lg);
}

.qr-corner-bl {
    bottom: 0;
    left: 0;
    border-right: none;
    border-top: none;
    border-bottom-left-radius: var(--rounded-lg);
}

.qr-corner-br {
    bottom: 0;
    right: 0;
    border-left: none;
    border-top: none;
    border-bottom-right-radius: var(--rounded-lg);
}

/* Scanner animation */
.qr-scan-line {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--primary-light), transparent);
    animation: qrScanLine 2s ease-in-out infinite;
}

@keyframes qrScanLine {
    0%, 100% { transform: translateY(0); opacity: 0; }
    50% { transform: translateY(277px); opacity: 1; }
}

/* Scanner footer */
.qr-scanner-footer {
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: var(--space-lg);
    padding-bottom: calc(var(--space-lg) + env(safe-area-inset-bottom));
    text-align: center;
}

.qr-scanner-instruction {
    font-size: var(--font-base);
    margin-bottom: var(--space-md);
    opacity: 0.9;
}

.qr-scanner-controls {
    display: flex;
    justify-content: center;
    gap: var(--space-md);
}

/* Haptic feedback support */
.haptic-light {
    /* CSS can't trigger haptics, but JS will use this class */
}

.haptic-medium {
    /* Medium haptic feedback */
}

.haptic-heavy {
    /* Heavy haptic feedback */
}

/* ========================================
   Touch-Friendly Form Optimizations
   ======================================== */

/* Form containers */
.form-container {
    padding: var(--space-lg);
    max-width: 100%;
}

/* Input fields */
.form-control {
    min-height: var(--touch-target-large);
    font-size: 16px; /* Prevent zoom on iOS */
    padding: 1rem;
    border: 2px solid #e9ecef;
    border-radius: var(--rounded-xl);
    background: #ffffff;
    transition: all var(--transition-base);
    touch-action: manipulation;
}

.form-control:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 0.2rem rgba(25, 135, 84, 0.15);
    outline: none;
}

/* Floating labels optimization */
.form-floating {
    position: relative;
    margin-bottom: var(--space-lg);
}

.form-floating label {
    position: absolute;
    top: 0;
    left: 0;
    padding: 1rem;
    pointer-events: none;
    transition: all var(--transition-base);
    color: var(--text-secondary);
    font-size: var(--font-base);
    transform-origin: 0 0;
}

.form-floating .form-control:focus ~ label,
.form-floating .form-control:not(:placeholder-shown) ~ label {
    transform: scale(0.85) translateY(-0.5rem) translateX(0.15rem);
    color: var(--primary);
}

/* Select dropdowns */
.form-select {
    min-height: var(--touch-target-large);
    font-size: 16px;
    padding: 1rem;
    border-radius: var(--rounded-xl);
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3e%3cpath fill='none' stroke='%23343a40' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='m1 6 7 7 7-7'/%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    background-size: 16px 12px;
    appearance: none;
}

/* Checkbox and radio optimization */
.form-check {
    margin-bottom: var(--space-md);
    min-height: var(--touch-target-min);
    display: flex;
    align-items: center;
}

.form-check-input {
    width: 1.5rem;
    height: 1.5rem;
    margin-right: var(--space-md);
    cursor: pointer;
}

.form-check-label {
    cursor: pointer;
    font-size: var(--font-base);
    line-height: 1.5;
    padding-top: 0.125rem;
}

/* File upload optimization */
.file-upload-container {
    border: 3px dashed #dee2e6;
    border-radius: var(--rounded-2xl);
    padding: var(--space-2xl);
    text-align: center;
    background: #f8f9fa;
    transition: all var(--transition-base);
    min-height: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.file-upload-container:hover,
.file-upload-container.dragover {
    border-color: var(--primary);
    background: rgba(25, 135, 84, 0.05);
}

.file-upload-icon {
    font-size: var(--font-4xl);
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
}

.file-upload-text {
    font-size: var(--font-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.file-upload-subtext {
    font-size: var(--font-sm);
    color: var(--text-secondary);
}

/* ========================================
   Performance Optimizations
   ======================================== */

/* Lazy loading images */
.lazy-image {
    opacity: 0;
    transition: opacity var(--transition-slow);
}

.lazy-image.loaded {
    opacity: 1;
}

/* Image placeholder */
.image-placeholder {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}

/* Optimized animations for mobile */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* GPU acceleration for smooth animations */
.gpu-accelerated {
    transform: translateZ(0);
    will-change: transform, opacity;
}

/* ========================================
   Device-Specific Optimizations
   ======================================== */

/* iPhone specific */
@supports (-webkit-appearance: none) and (stroke-color: transparent) {
    /* iPhone safe area */
    .safe-area-top {
        padding-top: env(safe-area-inset-top);
    }
    
    .safe-area-bottom {
        padding-bottom: env(safe-area-inset-bottom);
    }
    
    .safe-area-left {
        padding-left: env(safe-area-inset-left);
    }
    
    .safe-area-right {
        padding-right: env(safe-area-inset-right);
    }
    
    /* iPhone 14 Pro/Pro Max notch */
    @media screen and (device-width: 393px) and (device-height: 852px) and (-webkit-device-pixel-ratio: 3) {
        .dynamic-island-aware {
            padding-top: calc(env(safe-area-inset-top) + 10px);
        }
    }
}

/* Android specific */
@media screen and (max-width: 768px) {
    /* Android back button area */
    .android-nav-aware {
        padding-bottom: calc(env(safe-area-inset-bottom, 0px) + 10px);
    }
}

/* Samsung Galaxy specific optimizations */
@media screen and (device-width: 360px) and (device-height: 760px) {
    .galaxy-optimized {
        /* Samsung Galaxy S series optimizations */
    }
}

/* iPad specific */
@media screen and (min-device-width: 768px) and (max-device-width: 1024px) {
    .hero-content h1 {
        font-size: var(--font-4xl);
    }
    
    .hero-action {
        flex-direction: row;
        justify-content: center;
        max-width: 600px;
    }
    
    .qr-scanner-box {
        width: 350px;
        height: 350px;
    }
}

/* ========================================
   Responsive Breakpoints
   ======================================== */

/* Small phones (320px - 374px) */
@media (max-width: 374px) {
    :root {
        --font-base: 0.9rem;
        --font-lg: 1rem;
        --font-xl: 1.125rem;
        --font-2xl: 1.25rem;
    }
    
    .hero-content {
        padding: var(--space-md);
    }
    
    .hero-action .btn {
        font-size: var(--font-base);
        padding: 0.875rem 1.5rem;
    }
    
    .qr-scanner-box {
        width: 240px;
        height: 240px;
    }
}

/* Large phones (375px - 767px) */
@media (min-width: 375px) and (max-width: 767px) {
    .hero-content h1 {
        font-size: var(--font-3xl);
    }
    
    .hero-content p {
        font-size: var(--font-lg);
    }
    
    .qr-scanner-box {
        width: 300px;
        height: 300px;
    }
}

/* Tablets (768px - 1023px) */
@media (min-width: 768px) and (max-width: 1023px) {
    :root {
        --font-base: 1.125rem;
        --font-lg: 1.25rem;
        --font-xl: 1.5rem;
        --font-2xl: 1.75rem;
        --font-3xl: 2rem;
        --font-4xl: 2.5rem;
    }
    
    .hero-action {
        flex-direction: row;
        gap: var(--space-lg);
        max-width: 500px;
    }
    
    .hero-action .btn {
        flex: 1;
        max-width: 200px;
    }
    
    .form-container {
        padding: var(--space-2xl);
        max-width: 600px;
        margin: 0 auto;
    }
}

/* Desktop (1024px+) */
@media (min-width: 1024px) {
    .hero-carousel-mobile {
        height: 100vh;
    }
    
    .hero-slide {
        background-attachment: fixed;
    }
    
    .hero-content {
        max-width: 800px;
        margin: 0 auto;
    }
    
    .hero-action {
        flex-direction: row;
        gap: var(--space-xl);
        max-width: 600px;
    }
    
    .qr-scanner-fullscreen {
        /* Desktop QR scanner can be modal instead of fullscreen */
        position: fixed;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        width: 90vw;
        height: 90vh;
        max-width: 800px;
        max-height: 600px;
        border-radius: var(--rounded-2xl);
        overflow: hidden;
    }
}

/* ========================================
   Landscape Orientation Optimizations
   ======================================== */

@media screen and (orientation: landscape) and (max-height: 500px) {
    .hero-section {
        min-height: 100vh;
    }
    
    .hero-content {
        padding: var(--space-sm) var(--space-md);
    }
    
    .hero-content h1 {
        font-size: var(--font-xl);
        margin-bottom: var(--space-md);
    }
    
    .hero-content p {
        font-size: var(--font-sm);
        margin-bottom: var(--space-md);
    }
    
    .hero-action {
        flex-direction: row;
        gap: var(--space-sm);
    }
    
    .hero-action .btn {
        padding: 0.5rem 1rem;
        font-size: var(--font-sm);
        min-height: 40px;
    }
    
    .carousel-indicators {
        bottom: var(--space-sm);
    }
    
    /* QR scanner in landscape */
    .qr-scanner-header,
    .qr-scanner-footer {
        padding: var(--space-sm) var(--space-md);
    }
    
    .qr-scanner-box {
        width: 200px;
        height: 200px;
    }
}

/* ========================================
   Print Optimizations
   ======================================== */

@media print {
    .hero-section,
    .qr-scanner-fullscreen,
    .btn,
    .carousel-indicators {
        display: none !important;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
        color: #000;
        background: #fff;
    }
    
    .container {
        max-width: 100%;
        padding: 0;
    }
}

/* ========================================
   High DPI Display Optimizations
   ======================================== */

@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    /* Sharper borders and shadows for retina displays */
    .btn,
    .form-control,
    .qr-scanner-box {
        border-width: 0.5px;
    }
    
    .hero-content h1 {
        text-shadow: 1px 1px 4px rgba(0, 0, 0, 0.5);
    }
}

/* ========================================
   Accessibility Enhancements
   ======================================== */

/* Focus indicators for keyboard navigation */
.btn:focus-visible,
.form-control:focus-visible,
.carousel-indicators button:focus-visible {
    outline: 3px solid var(--primary);
    outline-offset: 2px;
    box-shadow: 0 0 0 0.2rem rgba(25, 135, 84, 0.25);
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    .btn {
        border: 2px solid currentColor;
    }
    
    .form-control {
        border: 2px solid currentColor;
    }
    
    .qr-scanner-box {
        border-color: #ffffff;
        box-shadow: none;
    }
}

/* Large text support */
@media (prefers-font-size: large) {
    :root {
        --font-base: 1.25rem;
        --font-lg: 1.5rem;
        --font-xl: 1.75rem;
        --font-2xl: 2rem;
        --font-3xl: 2.5rem;
        --font-4xl: 3rem;
    }
    
    .btn {
        min-height: calc(var(--touch-target-min) * 1.25);
        padding: 1rem 2rem;
    }
    
    .form-control {
        min-height: calc(var(--touch-target-large) * 1.25);
        padding: 1.25rem;
    }
}

/* ========================================
   Dark Mode Optimizations
   ======================================== */

@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #ffffff;
        --text-secondary: #b3b3b3;
        --text-light: #000000;
    }
    
    body {
        background: #1a1a1a;
        color: var(--text-primary);
    }
    
    .form-control {
        background: #2a2a2a;
        border-color: #404040;
        color: var(--text-primary);
    }
    
    .form-control:focus {
        border-color: var(--primary-light);
        background: #333333;
    }
    
    .file-upload-container {
        background: #2a2a2a;
        border-color: #404040;
    }
    
    .file-upload-container:hover,
    .file-upload-container.dragover {
        background: rgba(32, 201, 151, 0.1);
    }
    
    .image-placeholder {
        background: linear-gradient(90deg, #2a2a2a 25%, #3a3a3a 50%, #2a2a2a 75%);
    }
}