/* ==========================================
   BASE STYLES & VARIABLES
   ========================================== */

:root {
    /* Colors */
    --color-primary: #0066cc;
    --color-primary-dark: #0052a3;
    --color-primary-light: #e6f2ff;
    --color-success: #22c55e;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-info: #3b82f6;
    --color-neutral-50: #f9fafb;
    --color-neutral-100: #f3f4f6;
    --color-neutral-200: #e5e7eb;
    --color-neutral-300: #d1d5db;
    --color-neutral-400: #9ca3af;
    --color-neutral-500: #6b7280;
    --color-neutral-600: #4b5563;
    --color-neutral-700: #374151;
    --color-neutral-800: #1f2937;
    --color-neutral-900: #111827;

    /* Revenue Status Colors */
    --color-planned: #3b82f6;
    --color-invoiced: #f59e0b;
    --color-paid: #22c55e;
    --color-cancelled: #ef4444;
    --color-at-risk: #ec4899;

    /* 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;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'Monaco', 'Courier New', monospace;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size: 4rem;

    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    /* Shadows */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;

    /* Z-Index */
    --z-modal: 1000;
    --z-dropdown: 500;
    --z-sticky: 100;
}

/* ==========================================
   RESET & GLOBAL STYLES
   ========================================== */

*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    line-height: 1.5;
    color: var(--color-neutral-700);
    background-color: var(--color-neutral-50);
}

/* Typography */

h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: var(--font-weight-semibold);
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: var(--font-size-3xl);
}

h2 {
    font-size: var(--font-size-2xl);
}

h3 {
    font-size: var(--font-size-lg);
}

h4 {
    font-size: var(--font-size-base);
}

p {
    margin-bottom: var(--spacing-md);
}

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

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

/* ==========================================
   FORM ELEMENTS
   ========================================== */

input,
select,
textarea {
    font-family: inherit;
    font-size: inherit;
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="number"],
input[type="date"],
input[type="time"],
input[type="datetime-local"],
select,
textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--color-neutral-300);
    border-radius: var(--radius-md);
    background-color: white;
    color: var(--color-neutral-700);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
input[type="number"]:focus,
input[type="date"]:focus,
input[type="time"]:focus,
input[type="datetime-local"]:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

input[type="checkbox"],
input[type="radio"] {
    cursor: pointer;
}

textarea {
    resize: vertical;
    min-height: 100px;
}

/* ==========================================
   BUTTONS
   ========================================== */

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    transition: all var(--transition-fast);
}

.btn {
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--color-neutral-200);
    color: var(--color-neutral-700);
}

.btn-secondary:hover:not(:disabled) {
    background-color: var(--color-neutral-300);
}

.btn-small {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: var(--font-size-sm);
}

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

.btn-danger:hover:not(:disabled) {
    background-color: #dc2626;
}

/* ==========================================
   UTILITY CLASSES
   ========================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}