/**
 * Sakarya Klima Servisi - Modern Pure CSS Design System
 * Fast, lightweight, zero-dependency, ultra-clean design tokens.
 */

:root {
    /* Color Palette - Cool HVAC & High Contrast Theme */
    --color-primary: #0284c7;        /* Sky Cyan Blue */
    --color-primary-dark: #0369a1;   /* Deep Blue */
    --color-primary-light: #e0f2fe;  /* Ice Blue */
    --color-secondary: #0f172a;      /* Midnight Slate */
    --color-secondary-light: #1e293b;/* Slate Navy */
    
    --color-accent: #f97316;         /* Energetic Heat / CTA Orange */
    --color-accent-hover: #ea580c;   /* Deep Orange */
    --color-accent-light: #fff7ed;   /* Warm Tint */

    --color-whatsapp: #25D366;       /* WhatsApp Green */
    --color-whatsapp-dark: #128C7E;

    --color-bg-main: #f8fafc;        /* Crisp Ice White */
    --color-bg-card: #ffffff;        /* Pure White */
    --color-bg-alt: #f1f5f9;         /* Cool Light Gray */
    --color-border: #e2e8f0;         /* Soft Border */
    --color-border-hover: #cbd5e1;

    --color-text-main: #0f172a;      /* Slate 900 */
    --color-text-muted: #475569;     /* Slate 600 - High Contrast 5.9:1 */
    --color-text-light: #64748b;     /* Slate 500 */
    --color-text-inverse: #ffffff;   /* White */

    --color-success: #15803d;
    --color-danger: #dc2626;
    --color-warning: #d97706;

    /* Typography */
    --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    --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-4xl: 2.25rem;
    --font-size-5xl: 3rem;

    /* Spacing & Layout */
    --container-max-width: 1280px;
    --spacing-1: 0.25rem;
    --spacing-2: 0.5rem;
    --spacing-3: 0.75rem;
    --spacing-4: 1rem;
    --spacing-5: 1.25rem;
    --spacing-6: 1.5rem;
    --spacing-8: 2rem;
    --spacing-10: 2.5rem;
    --spacing-12: 3rem;
    --spacing-16: 4rem;
    --spacing-20: 5rem;

    /* Shadows & Radii */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
    --shadow-glow: 0 0 25px rgba(2, 132, 199, 0.25);

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: 350ms cubic-bezier(0.16, 1, 0.3, 1);
}

/* Reset & Box Sizing */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text-main);
    background-color: var(--color-bg-main);
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
    padding-bottom: 70px; /* Space for mobile sticky action bar */
}

@media (min-width: 992px) {
    body {
        padding-bottom: 0;
    }
}

img, svg, picture {
    display: block;
    max-width: 100%;
    height: auto;
}

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

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

button, input, select, textarea {
    font: inherit;
    color: inherit;
}

button {
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
    color: var(--color-secondary);
    font-weight: 700;
    line-height: 1.25;
    margin-bottom: var(--spacing-3);
    letter-spacing: -0.02em;
}

h1 { font-size: clamp(1.85rem, 4vw, 2.75rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.15rem); }
h3 { font-size: clamp(1.25rem, 2.5vw, 1.6rem); }
h4 { font-size: 1.2rem; }
h5 { font-size: 1rem; }
h6 { font-size: 0.875rem; }

p {
    margin-bottom: var(--spacing-4);
    color: var(--color-text-main);
}

p:last-child {
    margin-bottom: 0;
}

/* Layout Utilities */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--spacing-4);
    padding-right: var(--spacing-4);
}

.section {
    padding-top: var(--spacing-16);
    padding-bottom: var(--spacing-16);
}

.section-sm {
    padding-top: var(--spacing-10);
    padding-bottom: var(--spacing-10);
}

.section-alt {
    background-color: var(--color-bg-alt);
}

.section-dark {
    background-color: var(--color-secondary);
    color: var(--color-text-inverse);
}

.section-dark h1,
.section-dark h2,
.section-dark h3,
.section-dark h4 {
    color: var(--color-text-inverse);
}

.section-dark p {
    color: #cbd5e1;
}

.section-header {
    text-align: center;
    max-width: 750px;
    margin: 0 auto var(--spacing-12);
}

.section-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-2);
    padding: 0.35rem 0.85rem;
    font-size: var(--font-size-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    border-radius: var(--radius-full);
    background-color: var(--color-primary-light);
    color: var(--color-primary-dark);
    margin-bottom: var(--spacing-3);
}

.section-title {
    margin-bottom: var(--spacing-3);
}

.section-desc {
    font-size: var(--font-size-lg);
    color: #334155;
}

/* Flex & Grid Utilities */
.d-flex { display: flex; }
.flex-column { flex-direction: column; }
.align-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.gap-2 { gap: var(--spacing-2); }
.gap-4 { gap: var(--spacing-4); }
.gap-6 { gap: var(--spacing-6); }

.grid {
    display: grid;
    gap: var(--spacing-6);
}

.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

@media (max-width: 991px) {
    .grid-cols-3, .grid-cols-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
    .grid-cols-2, .grid-cols-3, .grid-cols-4 { grid-template-columns: 1fr; }
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-2 { margin-top: var(--spacing-2); }
.mt-4 { margin-top: var(--spacing-4); }
.mt-6 { margin-top: var(--spacing-6); }
.mt-8 { margin-top: var(--spacing-8); }
.mb-4 { margin-bottom: var(--spacing-4); }
.mb-6 { margin-bottom: var(--spacing-6); }

/* Accessibility (Screen Reader & Skip Link) */
.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;
}

.skip-link {
    position: absolute;
    top: -100px;
    left: 1rem;
    background: var(--color-primary);
    color: #ffffff;
    padding: 0.75rem 1.25rem;
    z-index: 9999;
    border-radius: var(--radius-md);
    font-weight: 700;
    text-decoration: none;
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: 1rem;
    color: #ffffff;
}