/* CDL Institute - Global Stylesheet v3.0 (Modern Web Aesthetic) */

/* 1. Root Variables & Base Styles */
:root {
    --brand-blue: #2563eb; /* A slightly richer blue */
    --brand-ink: #18181b;  /* zinc-900 */
    --bg-main: #f4f4f5;    /* zinc-100 */
    --bg-card: #ffffff;
    --text-primary: #18181b; /* zinc-900 */
    --text-secondary: #52525b; /* zinc-600 */
    --border-color: #e4e4e7; /* zinc-200 */
    --border-hover: #a1a1aa; /* zinc-400 */
    --border-active: var(--brand-ink);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* 2. Layout System */
.web-layout {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.content-card {
    width: 100%;
    max-width: 42rem; /* 672px */
    margin: 2rem auto;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 1.5rem; /* 24px */
    box-shadow: 0 25px 50px -12px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* For mobile-only views that shouldn't be centered on desktop */
.mobile-screen {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background-color: var(--bg-card);
}

/* 3. Component: Headers */
.app-header {
    position: sticky;
    top: 0;
    z-index: 10;
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-color);
}
.app-header-inner {
    height: 4rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1rem;
}
.app-header .leading, .app-header .trailing {
    flex: 1 0 0;
}
.app-header .leading { display: flex; justify-content: flex-start; }
.app-header .trailing { display: flex; justify-content: flex-end; }
.app-header .title { font-weight: 600; }

/* 4. Component: Content & Footers */
.app-content {
    padding: 1.5rem;
    flex-grow: 1;
}
.app-footer {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-card);
}
.app-footer-sticky {
    position: sticky;
    bottom: 0;
    z-index: 10;
}

/* 5. Component: Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-weight: 600;
    padding: 0.75rem 1.25rem;
    border-radius: 0.75rem; /* 12px */
    transition: all 150ms ease-in-out;
    border: none;
    cursor: pointer;
}
.btn:hover {
    transform: translateY(-1px);
}
.btn-primary {
    background-color: var(--brand-blue);
    color: white;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.3);
}
.btn-primary:hover {
    background-color: #1d4ed8; /* darker blue */
}
.btn-secondary {
    background-color: #e4e4e7; /* zinc-200 */
    color: var(--text-primary);
}
.btn-secondary:hover {
    background-color: #d4d4d8; /* zinc-300 */
}
.btn-dark {
    background-color: var(--brand-ink);
    color: white;
}
.btn-dark:hover {
    background-color: #27272a; /* zinc-800 */
}

/* 6. Component: Forms & Interactive Cards */
.form-label {
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text-primary);
}
.form-input, .form-select {
    width: 100%;
    margin-top: 0.25rem;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    background-color: #f9fafb; /* gray-50 */
    transition: all 150ms ease-in-out;
}
.form-input:focus, .form-select:focus {
    outline: none;
    border-color: var(--brand-blue);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
    background-color: white;
}

.selectable-card {
    display: block;
    padding: 1.25rem;
    border: 2px solid var(--border-color);
    border-radius: 1rem;
    cursor: pointer;
    transition: all 150ms ease-in-out;
}
.selectable-card:hover {
    border-color: var(--border-hover);
}
.selectable-card:has(:checked) {
    border-color: var(--brand-blue);
    background-color: #eff6ff; /* blue-50 */
    box-shadow: 0 4px 10px -2px rgba(37, 99, 235, 0.1);
}

/* 7. Component: List Card (for settings, profile, etc.) */
.list-card {
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    overflow: hidden;
}
.list-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
    transition: background-color 150ms ease-in-out;
}
.list-item:hover {
    background-color: #f4f4f5; /* zinc-100 */
}
.list-card > :last-child {
    border-bottom: none;
}

/* 8. Mobile Nav Bar */
.mobile-nav {
    position: sticky;
    bottom: 0;
    z-index: 50;
    background-color: white;
    border-top: 1px solid var(--border-color);
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    text-align: center;
    padding: 0.5rem;
}
.mobile-nav-link {
    padding: 0.5rem;
    border-radius: 0.5rem;
    color: #71717a; /* zinc-500 */
}
.mobile-nav-link:hover {
    background-color: var(--bg-main);
}
.mobile-nav-link.active {
    color: var(--brand-ink);
    font-weight: 600;
}
.mobile-nav-link.active .nav-icon { display: none; }
.mobile-nav-link:not(.active) .nav-icon-active { display: none; }