/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette - inspired by logo */
    --color-primary: #ff2a2a;
    --color-primary-light: #ff7f2a;
    --color-accent: #ffcc00;
    --color-dark: #800033;
    --color-text: #333333;
    --color-text-light: #666666;
    --color-bg: #ffffff;
    --color-bg-light: #f8f8f8;
    --color-border: #e0e0e0;
    --color-bg-purple: #BC85FF;
    --color-text-bg: #FF9142;
    --color-bg-orange: #ffac71;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-xxl: 1.5rem;
    --font-size-hero: 2rem;
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.2);
}

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-md);
    }
}

/* Header */
.header {
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-sm) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo img {
    height: 40px;
    width: auto;
    max-width: 200px;
}

/* Language Selector */
.language-selector {
    position: relative;
}

.lang-btn {
    background: var(--color-bg);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    min-width: 60px;
    transition: all var(--transition-fast);
}

.lang-btn:hover {
    border-color: var(--color-primary);
    background: var(--color-bg-light);
}

.lang-btn:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.lang-arrow {
    font-size: 0.7rem;
    transition: transform var(--transition-fast);
}

.lang-btn.active .lang-arrow {
    transform: rotate(180deg);
}

.lang-dropdown {
    position: absolute;
    top: calc(100% + 0.5rem);
    right: 0;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
    min-width: 150px;
    max-height: 300px;
    overflow-y: auto;
    display: none;
    z-index: 1001;
}

.lang-dropdown.show {
    display: block;
    animation: fadeIn var(--transition-fast);
}

.lang-option {
    width: 100%;
    padding: var(--spacing-sm);
    text-align: left;
    background: none;
    border: none;
    cursor: pointer;
    font-size: var(--font-size-sm);
    color: var(--color-text);
    transition: background var(--transition-fast);
    display: block;
}

.lang-option:hover {
    background: var(--color-bg-light);
}

.lang-option:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: -2px;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
    color: white;
    padding: var(--spacing-xxl) 0;
    text-align: center;
}

.hero-content {
    max-width: 600px;
    margin: 0 auto;
}

.hero-title {
    font-size: var(--font-size-hero);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xl);
    opacity: 0.95;
}

.download-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    align-items: center;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: white;
    color: var(--color-primary);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: var(--font-size-lg);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-md);
    min-width: 200px;
    justify-content: center;
    min-height: 44px;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    background: var(--color-accent);
    color: var(--color-dark);
}

.download-btn:active {
    transform: translateY(0);
}

.download-icon {
    font-size: 1.5rem;
}

@media (min-width: 768px) {
    .hero {
        padding: var(--spacing-xxl) 0 calc(var(--spacing-xxl) + 1rem);
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .hero-subtitle {
        font-size: var(--font-size-xl);
    }
    
    .download-buttons {
        flex-direction: row;
        justify-content: center;
    }
}

/* Section Styles */
section {
    padding: var(--spacing-lg) 0;
    border-top: 2px solid var(--color-primary);
}

.section-title {
    font-size: var(--font-size-xxl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.section-subtitle {
    text-align: center;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
    font-size: var(--font-size-lg);
}

/* Features Section */
.features {
    background: var(--color-bg-purple);
}

.feature-item {
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    opacity: 0;
    transform: translateY(20px);
    transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.feature-item.visible {
    opacity: 1;
    transform: translateY(0);
}

.feature-images {
    display: grid;
    grid-template-columns: 1fr 1fr;
    margin-bottom: var(--spacing-md);
}

.feature-img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    object-fit: cover;
    border: 1px solid #000;
    filter: drop-shadow(3px 5px 2px rgba(0, 0, 0, 0.35));
}

    .feature-img:nth-child(odd) {
        transform: rotate(-2deg);
    }

    .feature-img:nth-child(even) {
        transform: rotate(4deg);
    }

.feature-text {
    text-align: center;
}

.feature-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    background-color: var(--color-bg-orange);
    color: #000;
    margin-left: -2rem;
    margin-right: -2rem;
    padding: 1rem;
    text-align: center;
    border-top: 2px solid var(--color-primary);
    border-bottom: 2px solid var(--color-primary);
}

.feature-description {
    color: var(--color-text-light);
    font-size: var(--font-size-base);
    line-height: 1.7;
    text-align: center;
}

@media (min-width: 768px) {
    .feature-item {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: var(--spacing-lg);
        align-items: center;
    }
    
    .feature-item:nth-child(even) .feature-images {
        order: 2;
    }
    
    .feature-item:nth-child(even) .feature-text {
        order: 1;
    }
    
    .feature-text {
        text-align: left;
    }
    
    .feature-images {
        margin-bottom: 0;
    }
}

/* Description Section */
.description {
    background: var(--color-bg-orange);
}

.description-content {
    max-width: 800px;
    margin: 0 auto;
    font-weight: 600;
}

.description-text {
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-lg);
    line-height: 1.8;
    color: var(--color-text);
    text-align: justify;
}

/* Math Operations Section */
.math-operations {
    background: var(--color-bg-purple);
}

.accordion {
    max-width: 900px;
    margin: 0 auto;
}

.accordion-item {
    background: var(--color-bg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.accordion-header {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--color-bg);
    border: none;
    text-align: left;
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all var(--transition-fast);
    min-height: 44px;
}

.accordion-header:hover {
    background: var(--color-text-bg);
    color: #fff;
}

.accordion-item.active .accordion-header {
    background: var(--color-text-bg);
    color: #fff;
}

.accordion-header::after {
    content: '+';
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--color-primary);
    transition: transform var(--transition-fast);
}

.accordion-item.active .accordion-header::after {
    transform: rotate(45deg);
}

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal);
}

.accordion-item.active .accordion-content {
    max-height: 1000px;
}

.accordion-content p {
    padding: var(--spacing-md);
    color: var(--color-text-light);
    line-height: 1.7;
    text-align: center;
}

/* Footer */
.footer {
    background: var(--color-text);
    color: white;
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.footer-text {
    font-size: var(--font-size-sm);
    opacity: 0.8;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Utility Classes */
.visible {
    opacity: 1 !important;
    transform: translateY(0) !important;
}

/* RTL Support for Arabic */
[dir="rtl"] {
    direction: rtl;
}

[dir="rtl"] .header-content {
    flex-direction: row-reverse;
}

[dir="rtl"] .lang-dropdown {
    right: auto;
    left: 0;
}

[dir="rtl"] .feature-item {
    direction: rtl;
}

[dir="rtl"] .accordion-header {
    text-align: right;
}

[dir="rtl"] .accordion-header::after {
    order: -1;
}

/* Print Styles */
@media print {
    .header,
    .download-buttons,
    .lang-dropdown {
        display: none;
    }
    
    .hero {
        background: white;
        color: black;
    }
    
    .accordion-content {
        max-height: none !important;
    }
}