/* ========================================
   🎨 Air Quality Now - Enhanced Styles
   Modern Design with Glassmorphism & Animations
   ======================================== */

/* ========================================
   CSS Variables (테마 변수)
   ======================================== */
:root {
    /* Primary Colors */
    --primary-color: #3498db;
    --primary-light: #5dade2;
    --primary-dark: #2874a6;
    --secondary-color: #2ecc71;
    --accent-color: #e74c3c;

    /* Air Quality Index Colors */
    --aqi-good: #2ecc71;
    --aqi-good-light: #a8e6cf;
    --aqi-moderate: #f39c12;
    --aqi-moderate-light: #f8cf8d;
    --aqi-sensitive: #e67e22;
    --aqi-sensitive-light: #f0b27a;
    --aqi-unhealthy: #e74c3c;
    --aqi-unhealthy-light: #f5b7b1;
    --aqi-very-unhealthy: #9b59b6;
    --aqi-very-unhealthy-light: #d7bde2;
    --aqi-hazardous: #8b0000;
    --aqi-hazardous-light: #cd5c5c;

    /* Neutral Colors */
    --bg-color: #f8f9fa;
    --bg-secondary: #ffffff;
    --text-primary: #2c3e50;
    --text-secondary: #5f6c6d;
    /* Darkened from #7f8c8d for better contrast */
    --text-muted: #758586;
    /* Darkened from #95a5a6 for better contrast */
    --border-color: #e0e6ed;
    --border-light: #ecf0f1;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
    --shadow-hover: 0 12px 32px rgba(0, 0, 0, 0.18);

    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.3);

    /* Spacing */
    --spacing-xs: 5px;
    --spacing-sm: 10px;
    --spacing-md: 20px;
    --spacing-lg: 30px;
    --spacing-xl: 40px;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;

    /* Typography */
    --font-main: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Z-index layers */
    --z-dropdown: 1000;
    --z-header: 100;
    --z-modal: 2000;
}

/* ========================================
   Dark Mode Variables
   ======================================== */
.dark-mode {
    --bg-color: #1a1a2e;
    --bg-secondary: #16213e;
    --text-primary: #ffffff;
    --text-secondary: #b8b8b8;
    --text-muted: #8e8e8e;
    --border-color: #2d3748;
    --border-light: #252c3a;

    /* Enhanced Dark Mode Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 6px 16px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.6);
    --shadow-hover: 0 12px 32px rgba(0, 0, 0, 0.7);

    /* Glassmorphism for Dark Mode */
    --glass-bg: rgba(22, 33, 62, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
}

/* ========================================
   Base Styles & Reset
   ======================================== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-main);
    background: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition), color var(--transition);
    min-height: 100vh;
    overflow-x: hidden;
}

/* Enhanced background with gradient */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 400px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    opacity: 0.05;
    z-index: -1;
    pointer-events: none;
}

.dark-mode::before {
    opacity: 0.1;
}

/* Accessibility - Skip Link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-dark);
    /* Darkened for accessibility */
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    border-radius: 0 0 var(--radius-md) 0;
    z-index: 3000;
}

.skip-link:focus {
    top: 0;
}

/* ========================================
   Header
   ======================================== */
.header {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    position: sticky;
    top: 0;
    z-index: var(--z-header);
    box-shadow: var(--shadow-sm);
    animation: slideDown 0.5s ease;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }

    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 15px 25px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 15px;
    flex: 1;
}

/* Menu Toggle */
.menu-toggle {
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 24px;
    cursor: pointer;
    padding: 8px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    display: none;
}

.menu-toggle:hover {
    background: var(--border-light);
    transform: scale(1.05);
}

.menu-toggle:active {
    transform: scale(0.95);
}

/* Brand */
.brand {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.app-title {
    font-size: 24px;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 0;
}

.app-title i {
    color: var(--primary-color);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

.app-subtitle {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
    margin: 0;
}

/* Header Actions */
.header-actions {
    display: flex;
    align-items: center;
    gap: 10px;
}

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

.language-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-primary);
    font-family: var(--font-main);
    font-size: 14px;
    font-weight: var(--font-weight-medium);
}

.language-btn:hover {
    background: var(--border-light);
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.language-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 180px;
    max-height: 350px;
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-fast);
    z-index: var(--z-dropdown);
}

.language-dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.language-option {
    width: 100%;
    padding: 12px 16px;
    border: none;
    background: transparent;
    text-align: left;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-primary);
    font-family: var(--font-main);
    font-size: 14px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.language-option:hover {
    background: var(--border-light);
}

.language-option.active {
    background: linear-gradient(90deg, var(--primary-light), var(--primary-color));
    color: white;
    font-weight: var(--font-weight-semibold);
}

/* Theme Toggle */
.theme-toggle,
.notification-toggle {
    background: transparent;
    border: 1px solid var(--border-color);
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-primary);
    font-size: 18px;
}

.theme-toggle:hover,
.notification-toggle:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: rotate(15deg) scale(1.1);
    box-shadow: var(--shadow-sm);
}

.theme-toggle:active,
.notification-toggle:active {
    transform: rotate(15deg) scale(0.95);
}

.dark-mode .theme-toggle i::before {
    content: '\f185';
    /* fa-sun */
}

/* Quick Search Button */
.quick-search-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 18px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: 14px;
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
    white-space: nowrap;
}

.quick-search-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px) scale(1.05);
    box-shadow: var(--shadow);
}

.quick-search-btn:active {
    transform: translateY(0) scale(0.98);
}

.quick-search-btn i {
    font-size: 16px;
}

.quick-search-text {
    display: none;
}

@media (min-width: 640px) {
    .quick-search-text {
        display: inline;
    }
}

/* ========================================
   Navigation Menu
   ======================================== */
.nav-menu {
    display: flex;
    justify-content: center;
    gap: 8px;
    padding: 12px 25px;
    flex-wrap: wrap;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-light);
    max-width: 1400px;
    margin: 0 auto;
}

.nav-item {
    background: transparent;
    border: none;
    padding: 10px 20px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-secondary);
    font-family: var(--font-main);
    font-size: 14px;
    font-weight: var(--font-weight-medium);
    position: relative;
    overflow: hidden;
}

.nav-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(52, 152, 219, 0.2), transparent);
    transition: left 0.5s ease;
}

.nav-item:hover::before {
    left: 100%;
}

.nav-item:hover {
    color: var(--primary-color);
    background: var(--border-light);
    transform: translateY(-2px);
}

.nav-item.active {
    background: linear-gradient(135deg, var(--primary-light), var(--primary-color));
    color: white;
    box-shadow: var(--shadow-sm);
}

.nav-item i {
    font-size: 16px;
}

/* ========================================
   PWA Install Prompt
   ======================================== */
.install-prompt {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 15px 25px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
    box-shadow: var(--shadow);
    animation: slideDown 0.5s ease;
    position: relative;
    overflow: hidden;
}

.install-prompt::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    animation: shine 3s infinite;
}

@keyframes shine {
    to {
        left: 100%;
    }
}

.install-prompt.hidden {
    display: none;
}

.install-content {
    display: flex;
    align-items: center;
    gap: 12px;
    flex: 1;
}

.install-content i {
    font-size: 24px;
}

.install-actions {
    display: flex;
    gap: 10px;
}

.install-btn {
    background: white;
    color: var(--primary-color);
    border: none;
    padding: 10px 20px;
    border-radius: var(--radius-full);
    font-weight: var(--font-weight-semibold);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-main);
}

.install-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.dismiss-btn {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.dismiss-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: rotate(90deg);
}

/* ========================================
   Search Section - Enhanced
   ======================================== */
.search-section {
    max-width: 1200px;
    margin: 30px auto;
    padding: 0 25px;
}

.search-hint {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 20px;
    margin-bottom: 15px;
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.1), rgba(41, 128, 185, 0.05));
    border-left: 4px solid var(--primary-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 14px;
    animation: slideDown 0.4s ease-out;
}

.search-hint i {
    color: var(--primary-color);
    font-size: 16px;
}

.dark-mode .search-hint {
    background: linear-gradient(135deg, rgba(52, 152, 219, 0.15), rgba(41, 128, 185, 0.1));
}

.search-container {
    display: flex;
    gap: 12px;
    align-items: stretch;
}

/* Search Box with Glassmorphism */
.search-box {
    flex: 1;
    position: relative;
    display: flex;
    align-items: center;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 0 20px;
    transition: all var(--transition);
    box-shadow: var(--shadow-sm);
}

.search-box:focus-within {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(52, 152, 219, 0.1), var(--shadow);
    transform: translateY(-2px);
}

.search-icon {
    color: var(--text-secondary);
    font-size: 18px;
    margin-right: 12px;
    transition: color var(--transition-fast);
}

.search-box:focus-within .search-icon {
    color: var(--primary-color);
    animation: pulse 1s ease-in-out infinite;
}

.search-input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 16px 0;
    font-size: 16px;
    color: var(--text-primary);
    font-family: var(--font-main);
    outline: none;
}

.search-input::placeholder {
    color: var(--text-muted);
}

.clear-search {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 8px;
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
    opacity: 0;
    visibility: hidden;
}

.clear-search:not(.hidden) {
    opacity: 1;
    visibility: visible;
}

.clear-search:hover {
    background: var(--border-light);
    color: var(--accent-color);
    transform: rotate(90deg);
}

/* Search Button */
.search-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    margin-left: 10px;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: all var(--transition);
    font-family: var(--font-main);
    font-size: 15px;
    font-weight: 600;
    white-space: nowrap;
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.3);
}

.search-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(52, 152, 219, 0.4);
}

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

.search-btn i {
    font-size: 16px;
}

/* Location Button */
.location-btn {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    padding: 0 24px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    transition: all var(--transition);
    font-family: var(--font-main);
    font-size: 15px;
    font-weight: var(--font-weight-semibold);
    white-space: nowrap;
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
}

.location-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.location-btn:hover::before {
    width: 300px;
    height: 300px;
}

.location-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

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

/* 로딩 상태 스타일 */
.location-btn.loading {
    background: linear-gradient(135deg, var(--primary-light), var(--primary-color));
    cursor: wait;
    opacity: 0.8;
}

.location-btn.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: loading-slide 1.5s infinite;
}

@keyframes loading-slide {
    to {
        left: 100%;
    }
}

.location-btn.loading:hover {
    transform: none;
}

.location-btn:disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

/* ========================================
   Search Suggestions - Enhanced
   ======================================== */
.search-suggestions {
    position: relative;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    margin-top: 12px;
    box-shadow: var(--shadow-lg);
    max-height: 500px;
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-fast);
}

.search-suggestions:not(.hidden) {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.suggestion-section {
    padding: 12px 0;
}

.suggestion-section:not(:last-child) {
    border-bottom: 1px solid var(--border-light);
}

.suggestion-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    color: var(--text-secondary);
    font-size: 13px;
    font-weight: var(--font-weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.suggestion-header i {
    font-size: 14px;
}

.clear-recent {
    margin-left: auto;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px 8px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    font-size: 12px;
}

.clear-recent:hover {
    background: var(--border-light);
    color: var(--accent-color);
}

.suggestion-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 20px;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-primary);
    border-left: 3px solid transparent;
}

.suggestion-item:hover {
    background: var(--border-light);
    border-left-color: var(--primary-color);
}

.suggestion-item i {
    color: var(--text-secondary);
    font-size: 16px;
    width: 20px;
    text-align: center;
}

.suggestion-content {
    flex: 1;
}

.suggestion-name {
    font-weight: var(--font-weight-medium);
    margin-bottom: 2px;
}

.suggestion-country {
    font-size: 12px;
    color: var(--text-secondary);
}

/* ========================================
   Main Content
   ======================================== */
main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 30px 25px;
    min-height: calc(100vh - 400px);
}

/* Loading State */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 60px 20px;
    text-align: center;
}

.loading.hidden {
    display: none;
}

.loading-spinner {
    font-size: 48px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.loading-spinner i {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.loading p {
    color: var(--text-secondary);
    font-size: 16px;
}

/* Error Message */
.error-message {
    background: linear-gradient(135deg, #fee2e2, #fecaca);
    color: #991b1b;
    padding: 20px 24px;
    border-radius: var(--radius-lg);
    border-left: 4px solid #dc2626;
    margin: 20px 0;
    display: flex;
    align-items: center;
    gap: 15px;
    box-shadow: var(--shadow-sm);
    animation: shake 0.5s ease;
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-10px);
    }

    75% {
        transform: translateX(10px);
    }
}

.error-message.hidden {
    display: none;
}

.error-message i {
    font-size: 24px;
    flex-shrink: 0;
}

.dark-mode .error-message {
    background: linear-gradient(135deg, #7f1d1d, #991b1b);
    color: #fecaca;
}

/* ========================================
   AQI Display Section - Enhanced
   ======================================== */
.aqi-display {
    padding: 30px 0;
}

.aqi-display.hidden {
    display: none;
}

/* Location Info */
.location-info {
    text-align: center;
    margin-bottom: 40px;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.location-info h2 {
    font-size: 32px;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.location-info h2 i {
    color: var(--primary-color);
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

#countryName {
    font-size: 16px;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
}

/* ========================================
   AQI Circle - Enhanced with Animation
   ======================================== */
.aqi-circle-container {
    text-align: center;
    margin-bottom: 40px;
    animation: fadeIn 0.8s ease 0.2s both;
}

.aqi-circle {
    width: 220px;
    height: 220px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 25px;
    position: relative;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-slow);
    animation: scaleIn 0.8s ease 0.4s both;
}

@keyframes scaleIn {
    from {
        transform: scale(0);
        opacity: 0;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}

.aqi-circle:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-hover);
}

/* Pulse animation for circle */
.aqi-circle::before {
    content: '';
    position: absolute;
    top: -10px;
    left: -10px;
    right: -10px;
    bottom: -10px;
    border-radius: 50%;
    background: inherit;
    opacity: 0.3;
    animation: pulse-ring 2s ease-in-out infinite;
}

@keyframes pulse-ring {
    0% {
        transform: scale(1);
        opacity: 0.3;
    }

    50% {
        transform: scale(1.1);
        opacity: 0;
    }

    100% {
        transform: scale(1);
        opacity: 0;
    }
}

.aqi-value-container {
    text-align: center;
    z-index: 1;
}

.aqi-value {
    font-size: 64px;
    font-weight: var(--font-weight-bold);
    color: white;
    line-height: 1;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.aqi-label {
    font-size: 16px;
    color: rgba(255, 255, 255, 0.95);
    font-weight: var(--font-weight-medium);
    margin-top: 8px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.aqi-status {
    font-size: 24px;
    font-weight: var(--font-weight-semibold);
    margin-bottom: 10px;
    animation: fadeIn 1s ease 0.6s both;
}

.aqi-description {
    font-size: 15px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 15px auto;
    line-height: 1.8;
    animation: fadeIn 1.2s ease 0.8s both;
}

/* AQI Level Colors */
.aqi-good {
    background: linear-gradient(135deg, #00e400, #00b300);
}

.aqi-moderate {
    background: linear-gradient(135deg, #ffff00, #d4d400);
}

.aqi-unhealthy-sensitive {
    background: linear-gradient(135deg, #ff7e00, #cc6500);
}

.aqi-unhealthy {
    background: linear-gradient(135deg, #ff0000, #cc0000);
}

.aqi-very-unhealthy {
    background: linear-gradient(135deg, #8f3f97, #6e2f72);
}

.aqi-hazardous {
    background: linear-gradient(135deg, #7e0023, #5a0019);
}

/* ========================================
   Pollutants Grid - Enhanced
   ======================================== */
.pollutant-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin: 40px 0;
}

.pollutant-card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    padding: 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 16px;
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
    animation: fadeIn 0.6s ease both;
}

.pollutant-card:nth-child(1) {
    animation-delay: 0.1s;
}

.pollutant-card:nth-child(2) {
    animation-delay: 0.2s;
}

.pollutant-card:nth-child(3) {
    animation-delay: 0.3s;
}

.pollutant-card:nth-child(4) {
    animation-delay: 0.4s;
}

.pollutant-card:nth-child(5) {
    animation-delay: 0.5s;
}

.pollutant-card:nth-child(6) {
    animation-delay: 0.6s;
}

.pollutant-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(52, 152, 219, 0.1), transparent);
    transition: left 0.5s ease;
}

.pollutant-card:hover::before {
    left: 100%;
}

.pollutant-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: var(--primary-color);
}

.pollutant-icon {
    width: 60px;
    height: 60px;
    min-width: 60px;
    background: linear-gradient(135deg, var(--primary-light), var(--primary-color));
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 28px;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition);
}

.pollutant-card:hover .pollutant-icon {
    transform: rotate(10deg) scale(1.1);
}

.pollutant-info {
    flex: 1;
}

.pollutant-name {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: var(--font-weight-semibold);
    margin-bottom: 6px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.pollutant-value {
    font-size: 32px;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    line-height: 1;
    margin-bottom: 4px;
}

.pollutant-unit {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
}

/* ========================================
   Chart Container (NEW!)
   ======================================== */
.chart-container {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    padding: 30px;
    border-radius: var(--radius-lg);
    margin: 40px 0;
    box-shadow: var(--shadow);
    animation: fadeIn 0.8s ease 1s both;
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}

.chart-title {
    font-size: 20px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.chart-title i {
    color: var(--primary-color);
}

.chart-canvas {
    position: relative;
    height: 300px;
}

/* ========================================
   Update Button
   ======================================== */
.update-section {
    text-align: center;
    margin: 40px 0;
}

.update-btn {
    background: linear-gradient(135deg, var(--secondary-color), #27ae60);
    color: white;
    border: none;
    padding: 14px 32px;
    border-radius: var(--radius-full);
    font-size: 16px;
    font-weight: var(--font-weight-semibold);
    cursor: pointer;
    transition: all var(--transition);
    box-shadow: var(--shadow);
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--font-main);
}

.update-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.update-btn:active {
    transform: translateY(-1px);
}

.update-btn i {
    transition: transform var(--transition);
}

.update-btn:hover i {
    transform: rotate(180deg);
}

.last-updated {
    font-size: 13px;
    color: var(--text-secondary);
    margin-top: 12px;
}

/* ========================================
   Content Pages (Guide, Health, etc.)
   ======================================== */
.content-page {
    padding: 40px 0;
    animation: fadeIn 0.5s ease;
}

.content-page.hidden {
    display: none;
}

.content-article {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    padding: 40px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.content-header {
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--border-light);
}

.content-header h2 {
    font-size: 32px;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    margin-bottom: 10px;
}

.content-header p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
}

.content-article h3 {
    font-size: 24px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
    margin: 30px 0 15px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.content-article h3 i {
    color: var(--primary-color);
}

.content-article p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 15px;
}

.content-article ul,
.content-article ol {
    margin: 20px 0;
    padding-left: 30px;
}

.content-article li {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 10px;
}

/* Tip Cards */
.tip-card {
    background: linear-gradient(135deg, var(--aqi-good-light), rgba(46, 204, 113, 0.1));
    padding: 24px;
    border-radius: var(--radius-lg);
    margin: 20px 0;
    display: flex;
    gap: 20px;
    border-left: 4px solid var(--aqi-good);
    transition: all var(--transition);
}

.tip-card:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow);
}

.tip-icon {
    width: 60px;
    height: 60px;
    min-width: 60px;
    background: var(--aqi-good);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 28px;
}

.tip-content h4 {
    font-size: 18px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
    margin-bottom: 8px;
}

.tip-content p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Level Cards */
.level-card {
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: var(--radius-lg);
    margin: 20px 0;
    border-left: 4px solid var(--primary-color);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition);
}

.level-card:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow);
}

.level-header {
    display: flex;
    justify-content: flex-start;
    align-items: flex-start;
    gap: 20px;
    margin-bottom: 15px;
}

.level-icon {
    font-size: 40px;
    line-height: 1;
    flex-shrink: 0;
    width: 60px;
    text-align: center;
}

.level-info {
    flex: 1;
}

.level-name {
    font-size: 20px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
}

.level-range {
    font-size: 14px;
    color: var(--text-secondary);
    background: var(--border-light);
    padding: 6px 16px;
    border-radius: var(--radius-full);
    font-weight: var(--font-weight-medium);
}

.level-description {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Pollutant Detail Cards */
.pollutant-detail-card {
    background: var(--bg-secondary);
    padding: 30px;
    border-radius: var(--radius-lg);
    margin: 25px 0;
    box-shadow: var(--shadow);
    transition: all var(--transition);
}

.pollutant-detail-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.pollutant-detail-card h3 {
    font-size: 24px;
    font-weight: var(--font-weight-bold);
    color: var(--primary-color);
    margin-bottom: 15px;
}

.pollutant-detail-header {
    padding: 20px;
    border-radius: var(--radius-md);
    margin-bottom: 20px;
    color: white;
    text-align: center;
    box-shadow: var(--shadow-sm);
}

.pollutant-detail-header h3 {
    color: white !important;
    margin-bottom: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.pollutant-detail-header p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 16px;
    font-weight: var(--font-weight-medium);
}

.pollutant-detail-card h4 {
    font-size: 18px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
    margin: 20px 0 10px;
}

/* FAQ Items */
.faq-item {
    background: var(--bg-secondary);
    padding: 24px;
    border-radius: var(--radius-lg);
    margin: 15px 0;
    border: 1px solid var(--border-light);
    transition: all var(--transition);
}

.faq-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow);
}

.faq-question {
    font-size: 18px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
    margin-bottom: 10px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
}

.faq-question::before {
    content: 'Q:';
    color: var(--primary-color);
    font-weight: var(--font-weight-bold);
    flex-shrink: 0;
}

.faq-answer {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.7;
    padding-left: 28px;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-light);
    padding: 40px 25px;
    margin-top: 60px;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    text-align: center;
}

.footer-brand {
    font-size: 24px;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    margin-bottom: 20px;
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.footer-brand i {
    color: var(--primary-color);
}

.footer-links {
    display: flex;
    gap: 25px;
    justify-content: center;
    flex-wrap: wrap;
    margin: 20px 0;
}

.footer-link {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 14px;
    font-family: var(--font-main);
    padding: 8px 12px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.footer-link:hover {
    color: var(--primary-color);
    background: var(--border-light);
}

.footer-info {
    margin-top: 25px;
    padding-top: 25px;
    border-top: 1px solid var(--border-light);
}

.footer-info p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 10px;
}

.footer-info a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
    transition: color var(--transition-fast);
}

.footer-info a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

.copyright {
    font-size: 13px;
    color: var(--text-secondary);
    /* Darkened for accessibility */
}

/* ========================================
   Modal
   ======================================== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: var(--z-modal);
    padding: 20px;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
}

.modal:not(.hidden) {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    max-width: 500px;
    width: 100%;
    box-shadow: var(--shadow-lg);
    transform: scale(0.9);
    transition: transform var(--transition);
}

.modal:not(.hidden) .modal-content {
    transform: scale(1);
    animation: modalIn 0.3s ease;
}

@keyframes modalIn {
    from {
        transform: scale(0.9) translateY(50px);
        opacity: 0;
    }

    to {
        transform: scale(1) translateY(0);
        opacity: 1;
    }
}

.modal-header {
    padding: 30px 30px 20px;
    border-bottom: 1px solid var(--border-light);
}

.modal-header h2 {
    font-size: 24px;
    font-weight: var(--font-weight-bold);
    color: var(--text-primary);
    margin: 0;
}

.modal-body {
    padding: 30px;
}

.modal-body p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 20px;
}

.api-steps {
    background: var(--border-light);
    padding: 20px;
    border-radius: var(--radius-md);
    margin: 20px 0;
}

.api-steps h3 {
    font-size: 16px;
    font-weight: var(--font-weight-semibold);
    color: var(--text-primary);
    margin-bottom: 15px;
}

.api-steps ol {
    padding-left: 20px;
}

.api-steps li {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 10px;
}

.api-steps a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
}

.api-steps a:hover {
    text-decoration: underline;
}

.api-key-input {
    width: 100%;
    padding: 14px 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 15px;
    font-family: var(--font-main);
    color: var(--text-primary);
    background: var(--bg-color);
    transition: all var(--transition-fast);
}

.api-key-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(52, 152, 219, 0.1);
}

.save-api-btn {
    width: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: var(--font-weight-semibold);
    cursor: pointer;
    transition: all var(--transition);
    margin-top: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    font-family: var(--font-main);
    box-shadow: var(--shadow);
}

.save-api-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.api-note {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 15px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.api-note i {
    color: var(--secondary-color);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 900px) {
    .header-content {
        padding: 12px 20px;
    }

    .app-title {
        font-size: 20px;
    }

    .pollutant-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
    }

    .content-article {
        padding: 30px 25px;
    }
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-secondary);
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow-lg);
        max-height: calc(100vh - 70px);
        overflow-y: auto;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-item {
        width: 100%;
        justify-content: flex-start;
        padding: 12px 16px;
    }

    .search-container {
        flex-direction: column;
    }

    .location-btn span {
        display: none;
    }

    .location-btn {
        width: 100%;
        justify-content: center;
    }

    .location-btn span {
        display: inline;
    }

    .search-btn span {
        display: none;
    }

    .search-btn {
        padding: 12px 16px;
        min-width: auto;
    }
}

@media (max-width: 600px) {
    main {
        padding: 20px 15px;
    }

    .aqi-circle {
        width: 180px;
        height: 180px;
    }

    .aqi-value {
        font-size: 56px;
    }

    .pollutant-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .pollutant-card {
        flex-direction: column;
        align-items: center;
        text-align: center;
        padding: 20px 16px;
    }

    .tip-card {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }

    .content-article {
        padding: 25px 20px;
    }

    .content-header h2 {
        font-size: 26px;
    }

    .chart-container {
        padding: 20px 15px;
    }

    .chart-canvas {
        height: 250px;
    }
}

@media (max-width: 360px) {
    .app-title {
        font-size: 18px;
    }

    .aqi-circle {
        width: 160px;
        height: 160px;
    }

    .aqi-value {
        font-size: 48px;
    }

    .pollutant-value {
        font-size: 24px;
    }
}

/* ========================================
   Print Styles
   ======================================== */
@media print {

    .header-actions,
    .nav-menu,
    .search-section,
    .install-prompt,
    .update-btn,
    .footer-links {
        display: none !important;
    }

    body {
        background: white;
    }

    .content-article {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

/* ========================================
   Utilities
   ======================================== */
.hidden {
    display: none !important;
}

/* Smooth scrollbar */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--border-light);
}

::-webkit-scrollbar-thumb {
    background: var(--text-muted);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Selection */
::selection {
    background: var(--primary-light);
    color: white;
}

/* Focus visible */
*:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}