:root {
    /* Warm Monochromatic Palette */
    --canvas-primary: #FFFFFF;
    --canvas-secondary: #F7F6F3;
    --canvas-tertiary: #F3F1EE;

    /* Text Colors - Off-Black & Warm Grays */
    --text-primary: #2F3437;
    --text-secondary: #787774;
    --text-tertiary: #9B9894;

    /* Structural */
    --border-color: #EAEAEA;
    --border-subtle: rgba(0, 0, 0, 0.06);

    /* Muted Pastel Accents */
    --accent-red-bg: #FDEBEC;
    --accent-red-text: #9F2F2D;
    --accent-blue-bg: #E1F3FE;
    --accent-blue-text: #1F6C9F;
    --accent-green-bg: #EDF3EC;
    --accent-green-text: #346538;
    --accent-yellow-bg: #FBF3DB;
    --accent-yellow-text: #956400;

    /* Action Colors */
    --action-primary: #111111;
    --action-primary-hover: #333333;

    /* Shadows - Ultra-Subtle */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.06);

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border radius - Crisp */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;

    /* Transitions - Subtle */
    --transition-fast: 150ms cubic-bezier(0.16, 1, 0.3, 1);
    --transition-normal: 300ms cubic-bezier(0.16, 1, 0.3, 1);
    --transition-slow: 500ms cubic-bezier(0.16, 1, 0.3, 1);

    /* Z-index */
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-fixed: 300;
    --z-modal: 400;
}

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

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

body {
    font-family: 'Geist Sans', 'SF Pro Display', 'Helvetica Neue', 'Switzer', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--canvas-primary);
    overflow-x: hidden;
    font-feature-settings: 'ss01' 1;
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
    font-weight: 500;
    line-height: 1.2;
    color: var(--text-primary);
    margin: 0;
}

h1 {
    font-family: 'Instrument Serif', 'Lyon Text', 'Playfair Display', serif;
    font-size: 2.5rem;
    font-weight: 400;
    letter-spacing: -0.03em;
    line-height: 1.1;
}

h2 {
    font-family: 'Instrument Serif', 'Lyon Text', 'Playfair Display', serif;
    font-size: 1.875rem;
    font-weight: 400;
    letter-spacing: -0.02em;
    line-height: 1.15;
}

h3 {
    font-size: 1.25rem;
    font-weight: 500;
    letter-spacing: -0.01em;
}

h4 {
    font-size: 1rem;
    font-weight: 500;
}

code, pre, kbd {
    font-family: 'Geist Mono', 'SF Mono', 'JetBrains Mono', monospace;
}

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

a:hover {
    color: var(--primary-dark);
}

/* Navbar */
.navbar {
    position: sticky;
    top: 0;
    background: var(--canvas-primary);
    border-bottom: 1px solid var(--border-color);
    z-index: var(--z-sticky);
}

.navbar-container {
    max-width: 1920px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-xl);
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: var(--spacing-xl);
    align-items: center;
}

.navbar-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    transition: color var(--transition-fast);
    white-space: nowrap;
}

.navbar-logo:hover {
    color: var(--primary);
}

.logo-icon {
    font-size: 1.75rem;
}

.navbar-center {
    display: flex;
    justify-content: center;
}

.search-box {
    position: relative;
    width: 100%;
    max-width: 400px;
}

.search-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md) var(--spacing-sm) 2.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    background: var(--bg-tertiary);
    font-size: 0.875rem;
    color: var(--text-primary);
    transition: all var(--transition-fast);
}

.search-input:focus {
    outline: none;
    background: var(--bg-secondary);
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(91, 77, 255, 0.1);
}

.search-icon {
    position: absolute;
    left: var(--spacing-md);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-tertiary);
    pointer-events: none;
    font-size: 0.9rem;
}

.navbar-end {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    white-space: nowrap;
}

/* App Container */
.app-container {
    display: grid;
    grid-template-columns: 280px 1fr;
    min-height: calc(100vh - 60px);
    gap: 0;
}

/* Sidebar */
.sidebar {
    background: var(--canvas-primary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    position: sticky;
    top: 60px;
    height: calc(100vh - 60px);
}

.sidebar-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.sidebar-header h3 {
    font-size: 1rem;
    margin: 0;
}

#sidebar-toggle {
    display: none;
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    padding: var(--spacing-md) 0;
}

.tool-category {
    margin-bottom: var(--spacing-lg);
}

.category-title {
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
    margin: 0;
}

.tool-nav {
    display: flex;
    flex-direction: column;
}

.tool-btn {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    border-left: 3px solid transparent;
    position: relative;
}

.tool-btn:hover {
    background: var(--canvas-secondary);
    color: var(--text-primary);
}

.tool-btn.active {
    background: var(--canvas-secondary);
    color: var(--text-primary);
    border-left-color: var(--action-primary);
    font-weight: 500;
}

.tool-icon {
    display: none;
}

.tool-name {
    flex: 1;
    text-align: left;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sidebar-footer {
    padding: var(--spacing-md) 0;
    border-top: 1px solid var(--border-color);
}

/* Main Content */
.main-content {
    background: var(--canvas-primary);
    padding: var(--spacing-2xl);
    overflow-y: auto;
}

.tool-container {
    max-width: 1000px;
    margin: 0 auto;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    user-select: none;
    position: relative;
    overflow: hidden;
}

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

.btn:active::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--action-primary);
    color: #FFFFFF;
    border: 1px solid var(--action-primary);
}

.btn-primary:hover {
    background: var(--action-primary-hover);
    border-color: var(--action-primary-hover);
}

.btn-primary:active {
    transform: scale(0.98);
}

.btn-secondary {
    background: var(--canvas-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--canvas-tertiary);
    box-shadow: var(--shadow-sm);
}

.btn-success {
    background: var(--accent-green-bg);
    color: var(--accent-green-text);
    border: 1px solid var(--border-color);
}

.btn-success:hover {
    background: #E7EDE5;
    border-color: var(--border-color);
}

.btn-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    background: transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 1.2rem;
}

.btn-icon:hover {
    background: var(--bg-tertiary);
}

.btn-icon-small {
    width: 32px;
    height: 32px;
    padding: 0;
    border: none;
    background: transparent;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-icon-small:hover {
    background: var(--bg-tertiary);
}

/* Cards */
.card {
    background: var(--canvas-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    transition: all var(--transition-normal);
}

.card:hover {
    box-shadow: var(--shadow-sm);
    border-color: var(--border-subtle);
}

.card-header {
    margin-bottom: var(--spacing-lg);
}

.card-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin: 0;
    font-size: 1.5rem;
}

.card-icon {
    font-size: 2rem;
}

.card-body {
    margin-bottom: var(--spacing-lg);
}

.card-footer {
    display: flex;
    gap: var(--spacing-md);
    justify-content: flex-end;
    border-top: 1px solid var(--border-color);
    padding-top: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.95rem;
    letter-spacing: -0.01em;
}

.form-label-helper {
    display: block;
    margin-top: var(--spacing-xs);
    font-size: 0.8rem;
    color: var(--text-tertiary);
    font-weight: 400;
}

.form-input {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-family: 'Geist Mono', 'SF Mono', monospace;
    color: var(--text-primary);
    background: var(--canvas-secondary);
    transition: all var(--transition-fast);
}

.form-input:focus {
    outline: none;
    border-color: var(--text-primary);
    box-shadow: var(--shadow-sm);
}

.form-textarea {
    min-height: 120px;
    resize: vertical;
}

.form-select {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    color: var(--text-primary);
    background: var(--bg-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.form-select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(91, 77, 255, 0.1);
}

/* Checkboxes & Radios */
.checkbox-group,
.radio-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.checkbox-item,
.radio-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    cursor: pointer;
}

.checkbox-input,
.radio-input {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary);
}

.checkbox-label,
.radio-label {
    cursor: pointer;
    user-select: none;
    color: var(--text-primary);
}

/* Sliders */
.slider {
    width: 100%;
    height: 6px;
    border-radius: var(--radius-full);
    background: var(--border-color);
    outline: none;
    accent-color: var(--primary);
    cursor: pointer;
}

.slider::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary);
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(91, 77, 255, 0.3);
    transition: all var(--transition-fast);
}

.slider::-webkit-slider-thumb:hover {
    width: 24px;
    height: 24px;
    box-shadow: 0 4px 12px rgba(91, 77, 255, 0.4);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary);
    border: none;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(91, 77, 255, 0.3);
    transition: all var(--transition-fast);
}

.slider::-moz-range-thumb:hover {
    width: 24px;
    height: 24px;
    box-shadow: 0 4px 12px rgba(91, 77, 255, 0.4);
}

/* Output Area */
.output-area {
    background: var(--canvas-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    min-height: 100px;
    font-family: 'Geist Mono', 'SF Mono', monospace;
    font-size: 0.9rem;
    word-break: break-all;
    word-wrap: break-word;
    color: var(--text-primary);
    position: relative;
    overflow-x: auto;
}

.output-area-empty {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-tertiary);
    min-height: 100px;
}

/* Toast Container */
.toast-container {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    z-index: var(--z-modal);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.toast {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md) var(--spacing-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    min-width: 300px;
    animation: slideInRight 300ms ease-out;
}

.toast-success {
    border-color: var(--accent);
    background: linear-gradient(135deg, var(--bg-secondary) 0%, rgba(0, 200, 150, 0.05) 100%);
}

.toast-error {
    border-color: #EF4444;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, rgba(239, 68, 68, 0.05) 100%);
}

.toast-icon {
    font-size: 1.3rem;
    flex-shrink: 0;
}

.toast-message {
    flex: 1;
    font-size: 0.95rem;
}

/* Helpers */
.mt-xs { margin-top: var(--spacing-xs); }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }
.mt-2xl { margin-top: var(--spacing-2xl); }

.mb-xs { margin-bottom: var(--spacing-xs); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }
.mb-2xl { margin-bottom: var(--spacing-2xl); }

.text-center { text-align: center; }
.text-sm { font-size: 0.875rem; }
.text-xs { font-size: 0.75rem; }
.text-muted { color: var(--text-tertiary); }
.text-danger { color: #EF4444; }
.text-success { color: var(--accent); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-between { justify-content: space-between; }
.flex-center { justify-content: center; }
.items-center { align-items: center; }
.gap-sm { gap: var(--spacing-sm); }
.gap-md { gap: var(--spacing-md); }
.gap-lg { gap: var(--spacing-lg); }

.hidden { display: none; }
.w-full { width: 100%; }

/* Responsive */
@media (max-width: 768px) {
    .navbar-container {
        grid-template-columns: auto 1fr auto;
        gap: var(--spacing-md);
        padding: var(--spacing-md);
    }

    .search-box {
        max-width: 200px;
    }

    .app-container {
        grid-template-columns: 1fr;
        min-height: auto;
    }

    .sidebar {
        position: fixed;
        left: 0;
        top: 60px;
        width: 280px;
        height: calc(100vh - 60px);
        z-index: var(--z-fixed);
        transform: translateX(-100%);
        transition: transform var(--transition-normal);
        box-shadow: var(--shadow-lg);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    #sidebar-toggle {
        display: flex;
    }

    .main-content {
        padding: var(--spacing-lg);
    }

    .navbar-center {
        display: none;
    }

    .toast-container {
        bottom: var(--spacing-md);
        right: var(--spacing-md);
        left: var(--spacing-md);
    }

    .toast {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5rem;
    }

    .card {
        padding: var(--spacing-lg);
    }

    .card-footer {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}