/* IELTAI - Professional Design System */

:root {
    /* Professional Color Palette */
    /* Primary: Deep Royal Blue */
    --color-primary: #2563EB;
    --color-primary-dark: #1E40AF;
    --color-primary-light: #60A5FA;
    --color-primary-subtle: #EFF6FF;

    /* Secondary: Slate/Neutral */
    --color-secondary: #475569;
    --color-secondary-dark: #1E293B;
    --color-secondary-light: #94A3B8;

    /* Accents */
    --color-accent: #0EA5E9; /* Sky Blue */
    --color-success: #059669; /* Emerald */
    --color-warning: #D97706; /* Amber */
    --color-danger: #DC2626; /* Red */
    --color-info: #3B82F6; /* Blue */

    /* Backgrounds */
    --color-bg-body: #F8FAFC;
    --color-bg-surface: #FFFFFF;
    --color-bg-subtle: #F1F5F9;
    
    /* Text */
    --color-text-main: #0F172A;
    --color-text-muted: #64748B;
    --color-text-light: #94A3B8;
    --color-text-white: #FFFFFF;

    /* Typography */
    --font-primary: 'Inter', system-ui, -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    /* 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 */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --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 ease;
    --transition-base: 300ms ease;
}

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

body {
    font-family: var(--font-primary);
    color: var(--color-text-main);
    background-color: var(--color-bg-body);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--color-text-main);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.025em;
}

h1 { font-size: clamp(2rem, 5vw, 3rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.25rem); }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

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

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

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

/* Layout */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Navbar */
.navbar {
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--color-gray-200);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: var(--spacing-sm) 0;
}

.navbar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 4rem;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--color-text-main);
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
    list-style: none;
}

.nav-link {
    color: var(--color-text-muted);
    font-weight: 500;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-link:hover, .nav-link.active {
    color: var(--color-primary);
    background-color: var(--color-primary-subtle);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.625rem 1.25rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.9375rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: 1px solid transparent;
    gap: 0.5rem;
}

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

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

.btn-secondary {
    background-color: white;
    border-color: var(--color-gray-300);
    color: var(--color-text-main);
}

.btn-secondary:hover {
    background-color: var(--color-bg-subtle);
    border-color: var(--color-gray-400);
}

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

.btn-outline:hover {
    background-color: var(--color-primary-subtle);
}

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

.btn-danger:hover {
    background-color: #B91C1C;
}

/* Cards */
.card {
    background-color: var(--color-bg-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-gray-200);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

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

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

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--color-text-main);
}

.form-control {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--color-gray-300);
    border-radius: var(--radius-md);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-subtle);
}

/* Utilities */
.text-center { text-align: center; }
.text-right { text-align: right; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: 0.5rem; }
.gap-4 { gap: 1rem; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }
.w-full { width: 100%; }

/* Icons (SVG sizing) */
.icon {
    width: 1.25rem;
    height: 1.25rem;
    stroke-width: 2;
}

.icon-sm {
    width: 1rem;
    height: 1rem;
}

.icon-lg {
    width: 1.5rem;
    height: 1.5rem;
}

/* Footer */
.footer {
    background-color: var(--color-bg-surface);
    border-top: 1px solid var(--color-gray-200);
    padding: var(--spacing-2xl) 0;
    margin-top: auto;
}

/* Alerts */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    border: 1px solid transparent;
}

.alert-success {
    background-color: #ECFDF5;
    border-color: #A7F3D0;
    color: #065F46;
}

.alert-error {
    background-color: #FEF2F2;
    border-color: #FECACA;
    color: #991B1B;
}

.alert-info {
    background-color: #EFF6FF;
    border-color: #BFDBFE;
    color: #1E40AF;
}

/* Grid */
.grid {
    display: grid;
    gap: var(--spacing-lg);
}

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

@media (max-width: 768px) {
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .navbar-content { flex-direction: column; height: auto; padding: var(--spacing-md) 0; }
    .nav-links { flex-direction: column; width: 100%; gap: var(--spacing-sm); margin-top: var(--spacing-md); }
    .nav-link { width: 100%; justify-content: center; }
}