/* Modern CSS for Platform Bahan Ajar Guru (SaaS) */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700&family=Plus+Jakarta+Sans:wght@300;400;500;600;700&display=swap');

:root {
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Plus Jakarta Sans', sans-serif;

    /* Curated HSL Color Scheme */
    --color-bg: #0b0f19;
    --color-surface: #131b2e;
    --color-surface-glass: rgba(19, 27, 46, 0.7);
    --color-border-glass: rgba(255, 255, 255, 0.08);
    --color-primary: #6366f1;
    --color-primary-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-text: #f3f4f6;
    --color-text-muted: #9ca3af;
    --color-text-dark: #1f2937;
    
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    background-color: var(--color-bg);
    color: var(--color-text);
    font-family: var(--font-body);
    line-height: 1.6;
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(168, 85, 247, 0.15) 0px, transparent 50%);
    background-attachment: fixed;
    min-height: 100vh;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    letter-spacing: -0.02em;
}

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

a:hover {
    color: #8b5cf6;
}

/* Glassmorphism Card Utility */
.glass-card {
    background: var(--color-surface-glass);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--color-border-glass);
    border-radius: var(--radius-md);
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
    transition: var(--transition);
}

.glass-card:hover {
    border-color: rgba(255, 255, 255, 0.15);
    box-shadow: 0 15px 35px rgba(99, 102, 241, 0.1);
    transform: translateY(-2px);
}

/* Header & Navigation */
header.app-header {
    background: rgba(11, 15, 25, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border-glass);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1rem 2rem;
}

.header-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo a {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--color-primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

nav.main-nav ul {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.nav-link {
    color: var(--color-text);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-sm);
}

.nav-link:hover {
    background: rgba(255, 255, 255, 0.05);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-family: var(--font-heading);
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: var(--transition);
    gap: 0.5rem;
}

.btn-primary {
    background: var(--color-primary-gradient);
    color: white;
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.08);
    color: var(--color-text);
    border: 1px solid var(--color-border-glass);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

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

.btn-danger:hover {
    background: #dc2626;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--color-text-muted);
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--color-border-glass);
    border-radius: var(--radius-sm);
    color: var(--color-text);
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition);
}

.form-control:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
    background: rgba(255, 255, 255, 0.08);
}

/* Grid Layouts */
.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1.5rem;
}

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

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

@media (max-width: 768px) {
    .grid-cols-2, .grid-cols-3 {
        grid-template-columns: 1fr;
    }
}

/* Dashboard Layout */
.dashboard-wrapper {
    display: flex;
    min-height: calc(100vh - 70px);
}

.dashboard-sidebar {
    width: 260px;
    background: rgba(19, 27, 46, 0.9);
    border-right: 1px solid var(--color-border-glass);
    padding: 2rem 1.5rem;
}

.dashboard-content {
    flex: 1;
    padding: 2.5rem;
}

.sidebar-menu {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.sidebar-item a {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    color: var(--color-text-muted);
    border-radius: var(--radius-sm);
    font-weight: 500;
    transition: var(--transition);
}

.sidebar-item a:hover, .sidebar-item.active a {
    color: var(--color-text);
    background: rgba(99, 102, 241, 0.15);
}

/* Alert Boxes */
.alert {
    padding: 1rem 1.5rem;
    border-radius: var(--radius-sm);
    margin-bottom: 1.5rem;
    border-left: 4px solid transparent;
}

.alert-success {
    background: rgba(16, 185, 129, 0.15);
    border-color: var(--color-success);
    color: #a7f3d0;
}

.alert-danger {
    background: rgba(239, 68, 68, 0.15);
    border-color: var(--color-danger);
    color: #fca5a5;
}

/* Flipbook Interface */
.flipbook-viewport {
    width: 100%;
    height: calc(100vh - 120px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
}

.flipbook-container {
    width: 800px;
    height: 500px;
    position: relative;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    border-radius: 8px;
    overflow: hidden;
    background: #fdfdfd;
}

.flipbook-page {
    width: 100%;
    height: 100%;
    background-color: #ffffff;
    box-shadow: 0 0 5px rgba(0,0,0,0.1);
}

.flipbook-controls {
    margin-top: 1.5rem;
    display: flex;
    gap: 1rem;
    align-items: center;
}

.page-num {
    font-weight: 600;
    font-family: var(--font-heading);
}

/* Tabs */
.tabs-nav {
    display: flex;
    border-bottom: 1px solid var(--color-border-glass);
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.tab-btn {
    background: none;
    border: none;
    color: var(--color-text-muted);
    font-family: var(--font-heading);
    font-size: 1.1rem;
    font-weight: 600;
    padding: 0.75rem 1rem;
    cursor: pointer;
    position: relative;
    transition: var(--transition);
}

.tab-btn:hover, .tab-btn.active {
    color: var(--color-text);
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--color-primary-gradient);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* Drag and Drop list */
.sortable-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--color-border-glass);
    padding: 1rem 1.5rem;
    border-radius: var(--radius-sm);
    margin-bottom: 0.75rem;
    cursor: grab;
    transition: var(--transition);
}

.sortable-item:active {
    cursor: grabbing;
    background: rgba(255, 255, 255, 0.1);
    transform: scale(0.99);
}

.drag-handle {
    margin-right: 1rem;
    color: var(--color-text-muted);
}