:root {
    --primary: #1e3a8a; /* Academy Blue */
    --primary-hover: #172554;
    --secondary: #64748b;
    --accent: #d97706; /* Academy Gold */
    --danger: #ef4444;
    --bg: #f8fafc;
    --card-bg: rgba(255, 255, 255, 0.95);
    --text: #1e293b;
    --border: #e2e8f0;
    --radius: 12px;
    --shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.2);
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg);
    color: var(--text);
    min-height: 100vh;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

h1 {
    font-size: 2.5rem;
    font-weight: 600;
    background: linear-gradient(to right, var(--primary), var(--accent));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.actions {
    display: flex;
    gap: 1rem;
}

.mode-switcher {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.teacher-only.hidden-restrict {
    display: none !important;
}

.btn {
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    border: none;
    font-family: inherit;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn.primary { background-color: var(--primary); color: white; }
.btn.primary:hover { background-color: var(--primary-hover); transform: translateY(-2px); }

.btn.secondary { background-color: white; color: var(--secondary); border: 1px solid var(--border); }
.btn.secondary:hover { background-color: var(--bg); }

.btn.accent { background-color: var(--accent); color: white; }
.btn.accent:hover { opacity: 0.9; transform: translateY(-2px); }

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

.btn.small { padding: 0.5rem 1rem; font-size: 0.9rem; }

/* Dashboard Grid */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.mini-card {
    background: var(--card-bg);
    backdrop-filter: blur(8px);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    min-height: 150px;
}

.mini-card p {
    font-weight: 400;
    margin-bottom: 1rem;
}

.mini-card .footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: auto;
}

.mini-card .folder-label {
    font-size: 0.75rem;
    color: var(--secondary);
    background: var(--bg);
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 600;
}

#folder-select {
    min-width: 150px;
    outline: none;
}

/* Modals */
.modal {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.4);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

/* Folder Cards */
.folder-card {
    background: var(--card-bg);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    position: relative;
}

.folder-card:hover {
    border-color: var(--primary);
    transform: translateY(-5px);
    box-shadow: var(--shadow);
}

.folder-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary);
}

.folder-card .count {
    background: var(--bg);
    color: var(--secondary);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
}

.folder-card .folder-delete-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    opacity: 0;
    transition: opacity 0.2s;
}

.folder-card:hover .folder-delete-btn {
    opacity: 1;
}

#back-btn {
    margin-right: 1rem;
}

.hidden { display: none !important; }

.modal-content {
    background: white;
    padding: 2rem;
    border-radius: var(--radius);
    width: 100%;
    max-width: 500px;
    box-shadow: 0 20px 25px -5px rgb(0 0 0 / 0.1);
}

.form-group { margin-bottom: 1.5rem; }
.form-group label { display: block; margin-bottom: 0.5rem; font-weight: 600; }
.form-group input {
    width: 100%;
    padding: 0.75rem;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    outline: none;
}

.modal-actions { display: flex; justify-content: flex-end; gap: 1rem; margin-top: 1.5rem; }

/* Study View */
.study-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
    margin-top: 4rem;
}

.flashcard {
    width: 100%;
    max-width: 500px;
    height: 300px;
    perspective: 1000px;
    cursor: pointer;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
    box-shadow: var(--shadow);
    border-radius: var(--radius);
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front, .flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    border-radius: var(--radius);
    background: white;
    font-size: 1.5rem;
    border: 1px solid var(--border);
}

.flashcard-back {
    transform: rotateY(180deg);
    background: linear-gradient(135deg, white 0%, #f1f5f9 100%);
}

.study-controls {
    display: flex;
    align-items: center;
    gap: 2rem;
    font-weight: 600;
}