/*
 Copyright (c) 2026 John Talbot. All rights reserved.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
*/

:root {
    --bg-color: #000000;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #38bdf8;
    --accent-hover: #0ea5e9;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --danger: #f43f5e;
}

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

body {
    font-family: 'Outfit', sans-serif;
    color: var(--text-primary);
    background: radial-gradient(circle at top right, #1e293b, #000000);
    overflow: hidden;
    height: 100vh;
    width: 100vw;
}

#canvas-container {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
}

#ui-overlay {
    position: absolute;
    top: 20px;
    left: 20px;
    width: 350px;
    max-height: calc(100vh - 40px);
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 24px;
    z-index: 10;
    overflow-y: auto;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
    border-left: 1px solid rgba(255, 255, 255, 0.15);
    border-top: 1px solid rgba(255, 255, 255, 0.15);
    pointer-events: auto;
}

header {
    margin-bottom: 24px;
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 16px;
}

h1 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 4px;
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
}

.controls-section {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.label {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--accent-color);
    margin-bottom: 4px;
}

.btn-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
}

.actions-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
}

.btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
    padding: 8px 4px;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.95rem;
    transition: all 0.2s ease;
    text-align: center;
}

.btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-1px);
    border-color: rgba(255, 255, 255, 0.2);
}

.btn:active {
    transform: translateY(0);
}

.btn.danger {
    background: rgba(244, 63, 94, 0.1);
    border-color: rgba(244, 63, 94, 0.3);
    color: #fda4af;
}

.btn.active-move {
    background: var(--accent-color);
    color: white;
    border-color: white;
    transform: scale(1.05);
    box-shadow: 0 0 15px var(--accent-color);
}

.theory-section {
    margin-top: 10px;
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text-secondary);
}

.theory-section p {
    margin-bottom: 10px;
}

.theory-section b {
    color: var(--text-primary);
}

.math {
    font-family: 'Times New Roman', serif;
    font-style: italic;
    color: var(--accent-color);
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Back/breadcrumb link */
.back-link {
    display: inline-block;
    color: #60a5fa;
    text-decoration: none;
    font-size: 0.85rem;
    opacity: 0.7;
    transition: opacity 0.2s;
    margin-bottom: 8px;
}
.back-link:hover { opacity: 1; }


/* === Accessibility === */
:focus-visible {
    outline: 3px solid var(--accent-color, #38bdf8);
    outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}