/* ===== ROOT VARIABLES ===== */
:root {
    /* Primitive Color Tokens */
    --color-white: rgba(255, 255, 255, 1);
    --color-black: rgba(0, 0, 0, 1);
    --color-cream-50: rgba(252, 252, 249, 1);
    --color-cream-100: rgba(255, 255, 253, 1);
    --color-gray-200: rgba(245, 245, 245, 1);
    --color-gray-300: rgba(167, 169, 169, 1);
    --color-gray-400: rgba(119, 124, 124, 1);
    --color-slate-500: rgba(98, 108, 113, 1);
    --color-brown-600: rgba(94, 82, 64, 1);
    --color-charcoal-700: rgba(31, 33, 33, 1);
    --color-charcoal-800: rgba(38, 40, 40, 1);
    --color-slate-900: rgba(19, 52, 59, 1);
    --color-teal-300: rgba(50, 184, 198, 1);
    --color-teal-400: rgba(45, 166, 178, 1);
    --color-teal-500: rgba(33, 128, 141, 1);
    --color-teal-600: rgba(29, 116, 128, 1);
    --color-teal-700: rgba(26, 104, 115, 1);
    --color-teal-800: rgba(41, 150, 161, 1);
    --color-red-400: rgba(255, 84, 89, 1);
    --color-red-500: rgba(192, 21, 47, 1);
    --color-orange-400: rgba(230, 129, 97, 1);
    --color-orange-500: rgba(168, 75, 47, 1);

    /* Custom nature-inspired colors */
    --color-green-primary: #2d5016;
    --color-green-accent: #7cb342;
    --color-green-light: #aed581;
    --color-forest-dark: #1b3409;
    --color-earth: #8d6e63;

    /* Semantic tokens */
    --color-background: #f1f8e9;
    --color-surface: var(--color-cream-100);
    --color-text: var(--color-slate-900);
    --color-text-secondary: var(--color-slate-500);
    --color-primary: var(--color-green-accent);
    --color-primary-hover: var(--color-green-primary);
    --color-border: rgba(94, 82, 64, 0.2);

    /* Typography */
    --font-family-base: 'FKGroteskNeue', 'Geist', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    --font-family-mono: 'Berkeley Mono', ui-monospace, 'SFMono-Regular', 'Menlo', 'Monaco', 'Consolas', monospace;
    --font-size-xs: 11px;
    --font-size-sm: 12px;
    --font-size-base: 14px;
    --font-size-md: 14px;
    --font-size-lg: 16px;
    --font-size-xl: 18px;
    --font-size-2xl: 20px;
    --font-size-3xl: 24px;
    --font-size-4xl: 30px;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 550;
    --font-weight-bold: 600;

    /* Spacing */
    --space-4: 4px;
    --space-8: 8px;
    --space-12: 12px;
    --space-16: 16px;
    --space-20: 20px;
    --space-24: 24px;
    --space-32: 32px;

    /* Border Radius */
    --radius-sm: 6px;
    --radius-base: 8px;
    --radius-md: 10px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.02);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.04), 0 2px 4px -1px rgba(0, 0, 0, 0.02);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.04);

    /* Animation */
    --duration-fast: 150ms;
    --duration-normal: 250ms;
    --ease-standard: cubic-bezier(0.16, 1, 0.3, 1);
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
    :root {
        --color-background: #1a2e1a;
        --color-surface: #242324;
        --color-text: var(--color-gray-200);
        --color-text-secondary: rgba(167, 169, 169, 0.7);
        --color-green-primary: #7cb342;
        --color-green-accent: #aed581;
        --color-border: rgba(119, 124, 124, 0.3);
    }
}

/* ===== BASE STYLES ===== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: var(--font-size-base);
    font-family: var(--font-family-base);
    line-height: var(--line-height-normal);
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: var(--font-family-base);
    background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 50%, #a5d6a7 100%);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

/* ===== SHOOTING STARS CANVAS ===== */
#starsCanvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

/* ===== SCREEN LAYOUT ===== */
.screen {
    display: none;
    min-height: 100vh;
    position: relative;
    z-index: 1;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--space-20);
}

.screen.active {
    display: flex;
}

/* ===== LANGUAGE SELECTION SCREEN ===== */
.language-container {
    background: rgba(255, 255, 255, 0.95);
    padding: var(--space-32);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    text-align: center;
    max-width: 600px;
    width: 100%;
    backdrop-filter: blur(10px);
}

.logo {
    font-size: 64px;
    margin-bottom: var(--space-16);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

.language-container h1 {
    color: var(--color-green-primary);
    margin-bottom: var(--space-12);
    font-size: var(--font-size-4xl);
}

.subtitle {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-32);
    font-size: var(--font-size-sm);
}

.language-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-16);
    margin-bottom: var(--space-24);
}

.language-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-8);
    padding: var(--space-24) var(--space-16);
    background: white;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-standard);
    font-family: var(--font-family-base);
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-medium);
}

.language-btn:hover {
    background: var(--color-green-accent);
    color: white;
    border-color: var(--color-green-accent);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.language-btn .flag {
    font-size: 32px;
}

/* ===== MAIN APPLICATION CONTAINER ===== */
.app-container {
    background: rgba(255, 255, 255, 0.95);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    max-width: 900px;
    width: 100%;
    margin: var(--space-20) auto;
    padding: var(--space-32);
    backdrop-filter: blur(10px);
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-24);
    flex-wrap: wrap;
    gap: var(--space-16);
}

.header h1 {
    color: var(--color-green-primary);
    font-size: var(--font-size-3xl);
}

/* ===== TABS ===== */
.tabs {
    display: flex;
    gap: var(--space-8);
    margin-bottom: var(--space-24);
    border-bottom: 2px solid var(--color-border);
    overflow-x: auto;
    padding-bottom: var(--space-4);
}

.tab-btn {
    padding: var(--space-12) var(--space-20);
    background: transparent;
    border: none;
    border-bottom: 3px solid transparent;
    cursor: pointer;
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    transition: all var(--duration-normal) var(--ease-standard);
    white-space: nowrap;
}

.tab-btn:hover {
    color: var(--color-green-accent);
}

.tab-btn.active {
    color: var(--color-green-primary);
    border-bottom-color: var(--color-green-accent);
}

/* ===== TAB CONTENT ===== */
.tab-content-wrapper {
    min-height: 400px;
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease-in;
}

.tab-content.active {
    display: block;
}

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

/* ===== FORM GROUPS ===== */
.form-group {
    margin-bottom: var(--space-24);
    position: relative;
}

.form-group label {
    display: block;
    margin-bottom: var(--space-8);
    font-weight: var(--font-weight-medium);
    color: var(--color-text);
    font-size: var(--font-size-base);
}

.form-group input[type="number"],
.form-group input[type="text"],
.form-group select {
    width: 100%;
    padding: var(--space-12);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-base);
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    transition: border-color var(--duration-normal) var(--ease-standard);
    background: white;
}

.form-group input[type="number"]:focus,
.form-group input[type="text"]:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--color-green-accent);
}

.form-group input[type="range"] {
    width: 100%;
    height: 6px;
    background: var(--color-border);
    border-radius: var(--radius-sm);
    outline: none;
    -webkit-appearance: none;
}

.form-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--color-green-accent);
    border-radius: 50%;
    cursor: pointer;
    transition: background var(--duration-normal) var(--ease-standard);
}

.form-group input[type="range"]::-webkit-slider-thumb:hover {
    background: var(--color-green-primary);
}

.form-group input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--color-green-accent);
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: var(--space-12);
}

.checkbox-group input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.checkbox-group label {
    margin: 0;
    cursor: pointer;
}

/* ===== TOOLTIP ===== */
.tooltip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    background: var(--color-green-accent);
    color: white;
    border-radius: 50%;
    font-size: 12px;
    cursor: help;
    margin-left: var(--space-8);
    font-weight: bold;
}

/* ===== BUTTONS ===== */
.btn-primary,
.btn-secondary {
    padding: var(--space-12) var(--space-24);
    border: none;
    border-radius: var(--radius-base);
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    cursor: pointer;
    transition: all var(--duration-normal) var(--ease-standard);
}

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

.btn-primary:hover {
    background: var(--color-green-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: white;
    color: var(--color-green-primary);
    border: 2px solid var(--color-green-accent);
}

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

/* ===== EMISSIONS PREVIEW ===== */
.emissions-preview {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-20);
    background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
    border-radius: var(--radius-md);
    margin-top: var(--space-24);
    gap: var(--space-16);
    flex-wrap: wrap;
}

.preview-card {
    display: flex;
    align-items: center;
    gap: var(--space-12);
    font-size: var(--font-size-lg);
}

.emissions-value {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-green-primary);
}

/* ===== RESULTS CONTAINER ===== */
.results-container {
    background: rgba(255, 255, 255, 0.95);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    max-width: 900px;
    width: 100%;
    margin: var(--space-20) auto;
    padding: var(--space-32);
    backdrop-filter: blur(10px);
}

.results-container h1 {
    text-align: center;
    color: var(--color-green-primary);
    margin-bottom: var(--space-32);
    font-size: var(--font-size-4xl);
}

.results-card {
    background: white;
    padding: var(--space-32);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-bottom: var(--space-24);
}

.total-emissions {
    text-align: center;
    margin-bottom: var(--space-32);
}

.total-emissions span:first-child {
    display: block;
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-8);
}

.emissions-number {
    font-size: 64px;
    font-weight: var(--font-weight-bold);
    color: var(--color-green-primary);
    line-height: 1;
    margin: var(--space-16) 0;
}

.unit {
    display: block;
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
}

/* ===== CHART CONTAINER - CENTERED ===== */
.chart-container {
    display: flex;
    align-items: center;
    justify-content: center;
    max-width: 400px;
    margin: 0 auto var(--space-32);
    height: 300px;
    padding: var(--space-20);
}

.chart-container canvas {
    max-width: 100%;
    height: auto;
}

/* ===== MESSAGES ===== */
.trees-message {
    text-align: center;
    font-size: var(--font-size-xl);
    padding: var(--space-20);
    background: var(--color-bg-3);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-16);
    background: rgba(34, 197, 94, 0.1);
}

.comparison-message {
    text-align: center;
    font-size: var(--font-size-base);
    padding: var(--space-16);
    border-radius: var(--radius-md);
    font-weight: var(--font-weight-medium);
}

.comparison-message.good {
    background: rgba(34, 197, 94, 0.1);
    color: #2e7d32;
}

.comparison-message.average {
    background: rgba(245, 158, 11, 0.1);
    color: #f57c00;
}

.comparison-message.high {
    background: rgba(239, 68, 68, 0.1);
    color: #c62828;
}

/* ===== ACTION BUTTONS ===== */
.action-buttons {
    display: flex;
    gap: var(--space-16);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--space-24);
}

/* ===== MODAL ===== */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(5px);
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    padding: var(--space-32);
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 90%;
    position: relative;
    box-shadow: var(--shadow-lg);
}

.close {
    position: absolute;
    right: var(--space-16);
    top: var(--space-16);
    font-size: 28px;
    font-weight: bold;
    color: var(--color-text-secondary);
    cursor: pointer;
    line-height: 1;
}

.close:hover {
    color: var(--color-text);
}

.modal-content p {
    font-size: var(--font-size-lg);
    line-height: 1.6;
    margin-bottom: var(--space-24);
    color: var(--color-text);
}

/* ===== FOOTER ===== */
.footer {
    text-align: center;
    padding: var(--space-20);
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
    .app-container,
    .results-container {
        padding: var(--space-20);
        margin: var(--space-12);
    }

    .header {
        flex-direction: column;
        align-items: flex-start;
    }

    .tabs {
        flex-wrap: nowrap;
        overflow-x: auto;
    }

    .language-buttons {
        grid-template-columns: 1fr;
    }

    .emissions-preview {
        flex-direction: column;
    }

    .action-buttons {
        flex-direction: column;
    }

    .action-buttons button {
        width: 100%;
    }

    .emissions-number {
        font-size: 48px;
    }
}

/* ===== RTL SUPPORT FOR ARABIC ===== */
[dir="rtl"] .tooltip {
    margin-left: 0;
    margin-right: var(--space-8);
}

@font-face {
    font-family: 'FKGroteskNeue';
    src: url('https://sr2cdn.perplexity.ai/fonts/FKGroteskNeue.woff2') format('woff2');
}