/* IMPORT TYPOGRAPHY */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Orbitron:wght@400;600;700;900&display=swap');

/* PALETTE */
:root {
    --bg-primary: #0F172A; /* slate-900 - Deep space background */
    --bg-secondary: #1E293B; /* slate-800 - Card backgrounds */
    --accent-primary: #06B6D4; /* cyan-500 - CTAs and highlights */
    --accent-glow: #22D3EE; /* cyan-400 - Hover states */
    --text-primary: #F8FAFC; /* slate-50 - Primary text */
    --text-secondary: #94A3B8; /* slate-400 - Secondary text */
}

/* GENERAL STYLES */
body {
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    margin: 0;
    padding: 0;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Orbitron', sans-serif;
    color: var(--accent-primary);
    font-weight: 700;
}

h1 {
    letter-spacing: -0.025em;
    line-height: 1.1;
}

a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--accent-glow);
}

.btn-primary {
    background-color: var(--accent-primary);
    border-color: var(--accent-primary);
    color: var(--bg-primary) !important;
    font-weight: 600;
    transition: background-color 0.3s ease, border-color 0.3s ease, transform 0.2s ease;
}

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

.btn-outline-cyan {
    background: transparent;
    border: 2px solid rgba(6, 182, 212, 0.5);
    color: #06B6D4;
    padding: 0.75rem 1.5rem;
    border-radius: 12px;
    font-weight: 600;
    transition: all 0.3s ease;
    backdrop-filter: blur(4px);
}

.btn-outline-cyan:hover {
    background: rgba(6, 182, 212, 0.1);
    border-color: #06B6D4;
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(6, 182, 212, 0.3);
}

.form-control {
    background-color: var(--bg-secondary);
    border: 1px solid rgba(6, 182, 212, 0.15);
    color: var(--text-primary);
}

.form-control:focus {
    background-color: var(--bg-secondary);
    border-color: var(--accent-primary);
    color: var(--text-primary);
    box-shadow: 0 0 0 0.2rem rgba(6, 182, 212, 0.25);
}

/* HEADER */
header.navbar {
    background: rgba(15, 23, 42, 0.95) !important;
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(6, 182, 212, 0.1);
    height: 64px;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.navbar-brand, .nav-link {
    color: var(--text-primary) !important;
    font-family: 'Orbitron', sans-serif;
}

.navbar-brand:hover, .nav-link:hover {
    color: var(--accent-glow) !important;
}

/* LAYOUT & SPACING */
.main-content {
    padding: 3rem 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

.hero-section {
    margin-bottom: 4rem;
}

.puzzle-grid {
    gap: 2rem;
    margin-bottom: 3rem;
}

/* PUZZLE CARDS */
.puzzle-card {
    background: rgba(30, 41, 59, 0.7);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(6, 182, 212, 0.15);
    border-radius: 16px;
    overflow: hidden;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15), inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.puzzle-card:hover {
    transform: translateY(-6px) scale(1.03);
    border-color: rgba(6, 182, 212, 0.4);
    box-shadow: 0 16px 40px rgba(6, 182, 212, 0.25), 0 8px 16px rgba(0, 0, 0, 0.3);
}

.card-title {
    background: linear-gradient(135deg, #06B6D4, #22D3EE);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 600;
    font-size: 1.125rem;
}

.card-text {
    color: var(--text-secondary);
}

.card-body {
    background: var(--bg-secondary);
}

/* LEADERBOARD */
.leaderboard-sidebar {
    background: rgba(30, 41, 59, 0.7);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(6, 182, 212, 0.15);
    border-radius: 16px;
    padding: 20px;
}

.leaderboard-title {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: #F8FAFC;
}

.leaderboard-subtitle {
    color: #94A3B8;
    font-size: 0.875rem;
}

.leaderboard-sidebar table {
    width: 100%;
    color: var(--text-primary);
}

.leaderboard-sidebar th {
    color: var(--accent-primary);
    border-bottom: 1px solid rgba(6, 182, 212, 0.15);
}

.leaderboard-sidebar td {
    padding: 8px 4px;
    border-bottom: 1px solid rgba(30, 41, 59, 0.5);
}

/* PUZZLE PAGE */
#puzzle-board {
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 8px 24px rgba(6, 182, 212, 0.2);
    background: radial-gradient(circle at center, rgba(6, 182, 212, 0.1), transparent 60%);
    border: 1px solid rgba(6, 182, 212, 0.2);
    padding: 10px;
}

#pieces-tray {
    border-radius: 16px;
    padding: 1rem;
    background: radial-gradient(circle at top, rgba(248, 250, 252, 0.05), transparent 70%), var(--bg-secondary);
    border: 1px solid rgba(248, 250, 252, 0.1);
    min-height: 200px;
    max-height: 50vh;
    overflow-y: auto;
}

.drop-zone {
    border: 1px dashed rgba(248, 250, 252, 0.2);
    border-radius: 8px;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.drop-zone.hovered {
    background-color: rgba(6, 182, 212, 0.2);
    border-color: var(--accent-glow);
}

.puzzle-piece {
    cursor: grab;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
    border-radius: 6px;
}

.puzzle-piece:active {
    cursor: grabbing;
}

.puzzle-piece:hover {
    transform: scale(1.05);
    box-shadow: 0 0 15px var(--accent-glow);
}

/* COMPLETION MODAL */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    opacity: 1;
    transition: opacity 0.3s ease;
}

.modal-backdrop.hidden {
    opacity: 0;
    pointer-events: none;
}

.modal-content {
    background: var(--bg-secondary);
    padding: 2rem 3rem;
    border-radius: 16px;
    border: 1px solid rgba(6, 182, 212, 0.2);
    text-align: center;
    position: relative;
    transform: scale(1);
    transition: transform 0.3s ease;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.modal-backdrop.hidden .modal-content {
    transform: scale(0.9);
}

.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color 0.3s ease;
}

.close-btn:hover {
    color: var(--text-primary);
}

.modal-content h2 {
    margin-bottom: 0.5rem;
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.modal-content .score {
    color: var(--text-primary);
    font-size: 1.25rem;
    margin-bottom: 2rem;
}

.modal-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* UTILITIES & OVERRIDES */
main {
    background: linear-gradient(135deg, var(--bg-primary) 0%, #131c31 100%);
    padding: 40px 24px;
    min-height: calc(100vh - 64px);
}

.bg-dark {
    background-color: var(--bg-secondary) !important;
}

.text-white {
    color: var(--text-primary) !important;
}

.border-dark {
    border-color: #06b6d4 !important;
}

.table-dark {
    --bs-table-bg: var(--bg-secondary);
    --bs-table-border-color: var(--accent-primary);
}

/* Toggle Switch styles */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 28px;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #4f5d73; /* Darker grey for off state */
    transition: .4s;
    border-radius: 28px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px;
    width: 20px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--accent-primary);
}

input:focus + .slider {
    box-shadow: 0 0 1px var(--accent-primary);
}

input:checked + .slider:before {
    transform: translateX(22px);
}