:root {
    /* Brand Colors - Standardized */
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --secondary-hover: #2980b9;
    --accent-color: #e74c3c;
    --success-color: #2ecc71;
    --warning-color: #f1c40f;
    
    /* UI Colors */
    --background-color: #f8f9fa;
    --bg-card: #ffffff;
    --text-color: #333;
    --text-light: #666;
    --border-color: #e9ecef;
    
    /* Shadows - Modern & Soft */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.05), 0 1px 2px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.05), 0 4px 6px -2px rgba(0,0,0,0.025);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2.5rem;
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    
    /* Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: var(--secondary-color);
    text-decoration: none;
    transition: var(--transition-fast);
}

a:hover {
    color: var(--secondary-hover);
    text-decoration: underline;
}

/* Layout */
.container {
    width: 100%;
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.main-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    padding-bottom: var(--spacing-lg);
}

/* Header */
.site-header {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-sm) 0;
    margin-bottom: var(--spacing-lg);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(8px);
    background-color: rgba(255, 255, 255, 0.95);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

@media (max-width: 600px) {
    .header-content {
        flex-wrap: wrap;
    }
    
    .main-nav {
        order: 2;
        width: 100%;
        justify-content: center;
        margin-top: 0.5rem;
    }
}

.site-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.site-title a {
    color: inherit;
    text-decoration: none;
}

/* Footer */
.site-footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-lg) 0;
    margin-top: auto;
    text-align: center;
    color: var(--text-light);
    font-size: 0.875rem;
}

/* Components */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
    margin-bottom: var(--spacing-md);
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.6rem 1.25rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: 1px solid transparent;
    cursor: pointer;
    font-size: 0.95rem;
    transition: var(--transition-fast);
    gap: 0.5rem;
    line-height: 1.2;
    user-select: none;
}

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

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

.btn-primary:hover {
    background-color: var(--secondary-hover);
    box-shadow: 0 4px 6px rgba(52, 152, 219, 0.25);
    transform: translateY(-1px);
    text-decoration: none;
}

.btn-secondary {
    background-color: white;
    border-color: var(--border-color);
    color: var(--text-color);
}

.btn-secondary:hover {
    background-color: #f8f9fa;
    border-color: #cbd5e0;
    color: var(--primary-color);
}

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

.btn-danger:hover {
    background-color: var(--accent-color);
    color: white;
    text-decoration: none;
}

.btn-text {
    background: transparent;
    color: var(--text-light);
    padding: 0.4rem 0.8rem;
}

.btn-text:hover {
    color: var(--text-color);
    background: rgba(0,0,0,0.03);
}

.btn-block {
    display: flex;
    width: 100%;
}

/* Forms */
.form-control {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition-fast);
    background-color: #fff;
}

.form-control:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

/* Lang Switcher */
.lang-switcher {
    position: relative;
}

.lang-select {
    appearance: none;
    background-color: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.4rem 2rem 0.4rem 0.8rem;
    font-size: 0.875rem;
    color: var(--text-color);
    cursor: pointer;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%237f8c8d' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.5rem center;
}

.lang-select:hover {
    border-color: var(--secondary-color);
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 10px;
    pointer-events: none;
}

.toast {
    background: white;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-lg);
    padding: 1rem;
    min-width: 300px;
    max-width: 400px;
    border-left: 4px solid var(--secondary-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    animation: slideIn 0.3s ease-out forwards;
    opacity: 0;
    transform: translateX(100%);
    pointer-events: auto;
}

.toast-success { border-left-color: var(--success-color); }
.toast-error { border-left-color: var(--accent-color); }
.toast-info { border-left-color: var(--secondary-color); }

.toast.hide {
    animation: slideOut 0.3s ease-in forwards;
}

@keyframes slideIn {
    to { opacity: 1; transform: translateX(0); }
}

@keyframes slideOut {
    to { opacity: 0; transform: translateX(100%); }
}

/* Loading Spinner */
.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

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

/* Tool Grid (Homepage) */
.tool-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-md);
}

.tool-card {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.tool-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
}

.tool-title {
    font-size: 1.25rem;
    margin: 0 0 0.5rem 0;
    font-weight: 700;
}

.tool-desc {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    flex: 1;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s;
    backdrop-filter: blur(2px);
}

.modal-overlay.show {
    opacity: 1;
    visibility: visible;
}

.modal-box {
    background: var(--bg-card);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    max-width: 400px;
    width: 90%;
    transform: scale(0.95);
    transition: transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.modal-overlay.show .modal-box {
    transform: scale(1);
}