/* Ykhtech Main Stylesheet - Production-Grade Responsive Design */

/* ===== CSS Variables (Theme Base) ===== */
:root {
    /* Primary colors - will be overridden by theme files */
    --primary-color: #1E40AF;
    --primary-dark: #1E3A8A;
    --primary-light: #3B82F6;
    --secondary-color: #F97316;
    --secondary-dark: #EA580C;
    --secondary-light: #FB923C;

    /* Background & Surface */
    --bg-color: #FFFFFF;
    --bg-secondary: #F8FAFC;
    --surface: #FFFFFF;
    --surface-elevated: #FFFFFF;

    /* Text colors */
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --text-tertiary: #9CA3AF;
    --text-inverse: #F9FAFB;

    /* Border & Divider */
    --border-color: #E5E7EB;
    --border-hover: #D1D5DB;
    --divider: #F3F4F6;

    /* Status colors */
    --success: #10B981;
    --warning: #F59E0B;
    --error: #EF4444;
    --info: #3B82F6;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 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);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Spacing scale */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;

    /* Border radius */
    --radius-sm: 0.25rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
    --font-mono: 'IBM Plex Mono', 'SF Mono', Consolas, monospace;

    /* Layout */
    --container-max: 1280px;
    --container-wide: 1440px;
    --header-height: 64px;
}

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

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

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-color);
    transition: background-color var(--transition-base), color var(--transition-base);
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    margin-bottom: var(--space-4);
}

h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 800;
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 1.875rem);
}

h4 {
    font-size: clamp(1.25rem, 2.5vw, 1.5rem);
}

h5 {
    font-size: 1.125rem;
}

h6 {
    font-size: 1rem;
}

p {
    margin-bottom: var(--space-4);
    color: var(--text-secondary);
}

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

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

strong {
    font-weight: 600;
    color: var(--text-primary);
}

/* ===== Layout ===== */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-6);
    width: 100%;
}

.container-wide {
    max-width: var(--container-wide);
    margin: 0 auto;
    padding: 0 var(--space-8);
}

.container-full {
    width: 100%;
    padding: 0 var(--space-4);
}

/* ===== Grid System ===== */
.grid {
    display: grid;
    gap: var(--space-6);
}

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

.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);
}

.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* ===== Flexbox Utilities ===== */
.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 0.9375rem;
    font-weight: 600;
    line-height: 1;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    gap: var(--space-2);
    white-space: nowrap;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

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

.btn-secondary:hover {
    background-color: var(--secondary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background-color: transparent;
    color: var(--text-primary);
    border: 1.5px solid var(--border-color);
}

.btn-outline:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background-color: rgba(30, 64, 175, 0.05);
}

.btn-ghost {
    background-color: transparent;
    color: var(--text-secondary);
}

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

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.0625rem;
}

/* ===== Cards ===== */
.card {
    background-color: var(--surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    overflow: hidden;
    transition: all var(--transition-base);
}

.card:hover {
    border-color: var(--primary-light);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.card-header {
    padding: var(--space-6);
    border-bottom: 1px solid var(--border-color);
}

.card-body {
    padding: var(--space-6);
}

.card-footer {
    padding: var(--space-6);
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
}

.card-image {
    width: 100%;
    height: 220px;
    object-fit: cover;
    display: block;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--space-2);
    color: var(--text-primary);
}

.card-description {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    line-height: 1.6;
}

/* ===== Badges ===== */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 9999px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-primary {
    background-color: rgba(30, 64, 175, 0.1);
    color: var(--primary-color);
}

.badge-success {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--success);
}

.badge-warning {
    background-color: rgba(245, 158, 11, 0.1);
    color: var(--warning);
}

/* ===== Forms ===== */
.form-group {
    margin-bottom: var(--space-6);
}

.form-label {
    display: block;
    font-size: 0.9375rem;
    font-weight: 500;
    margin-bottom: var(--space-2);
    color: var(--text-primary);
}

.form-input,
.form-textarea,
.form-select {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 0.9375rem;
    font-family: inherit;
    color: var(--text-primary);
    background-color: var(--surface);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius);
    transition: all var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.1);
}

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

/* ===== Sections ===== */
.section {
    padding: var(--space-20) 0;
}

.section-sm {
    padding: var(--space-12) 0;
}

.section-lg {
    padding: 6rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-16);
}

.section-title {
    font-size: clamp(2rem, 4vw, 2.5rem);
    margin-bottom: var(--space-4);
    position: relative;
    display: inline-block;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 2px;
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.7;
}

/* ===== Navigation ===== */
.nav-link {
    position: relative;
    padding: 0.5rem 1rem;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-link:hover {
    color: var(--text-primary);
}

.nav-link.active {
    color: var(--primary-color);
}

/* ===== Images ===== */
img {
    max-width: 100%;
    height: auto;
    display: block;
}

.img-responsive {
    width: 100%;
    height: auto;
}

.img-cover {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* ===== Utilities ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--primary-color); }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-tertiary); }

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

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

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

/* ===== Animations ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.fade-in {
    animation: fadeIn var(--transition-slow) ease-out;
}

.slide-up {
    animation: slideUp var(--transition-slow) ease-out;
}

/* ===== Responsive Design ===== */

/* Tablet: 768px - 1024px */
@media (max-width: 1024px) {
    :root {
        --space-20: 4rem;
        --space-16: 3rem;
    }

    .container {
        padding: 0 var(--space-4);
    }

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

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

    .section {
        padding: var(--space-16) 0;
    }

    .section-lg {
        padding: var(--space-20) 0;
    }
}

/* Mobile: < 768px */
@media (max-width: 768px) {
    :root {
        --space-20: 3rem;
        --space-16: 2.5rem;
        --space-12: 2rem;
    }

    .container {
        padding: 0 var(--space-4);
    }

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

    .grid {
        gap: var(--space-4);
    }

    .section {
        padding: var(--space-12) 0;
    }

    .section-header {
        margin-bottom: var(--space-8);
    }

    .card-image {
        height: 200px;
    }

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

    .btn-sm {
        width: auto;
    }

    /* Hide on mobile */
    .hide-mobile {
        display: none !important;
    }

    /* Stack flexbox on mobile */
    .flex-mobile-col {
        flex-direction: column;
    }
}

/* Small mobile: < 480px */
@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    .container {
        padding: 0 var(--space-3);
    }

    .card-body {
        padding: var(--space-4);
    }
}

/* ===== Print Styles ===== */
@media print {
    .no-print {
        display: none !important;
    }

    body {
        background: white;
        color: black;
    }

    .card {
        border: 1px solid #ddd;
        box-shadow: none;
    }
}