/* ==========================================================================
   CSS Battle Playground — Styles
   Theme: Dark, Indigo/Cyan, glassmorphism
   ========================================================================== */
:root {
    --c-primary: #6366F1;
    --c-primary-glow: rgba(99, 102, 241, .2);
    --c-accent: #22D3EE;
    --c-accent-glow: rgba(34, 211, 238, .15);
    --c-bg: #0F172A;
    --c-bg-card: rgba(30, 41, 59, .6);
    --c-bg-input: rgba(15, 23, 42, .9);
    --c-surface: rgba(51, 65, 85, .4);
    --c-border: rgba(148, 163, 184, .12);
    --c-text: #F1F5F9;
    --c-text-sec: #94A3B8;
    --c-text-muted: #64748B;
    --c-success: #10B981;
    --c-warning: #F59E0B;
    --c-danger: #EF4444;
    --radius: 12px;
    --radius-sm: 8px;
    --radius-full: 9999px;
    --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'SF Mono', 'Fira Code', monospace;
    --transition: 250ms ease
}

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased
}

body {
    font-family: var(--font);
    background: var(--c-bg);
    color: var(--c-text);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden
}

.bg-glow {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    pointer-events: none;
    z-index: 0;
    opacity: .3
}

.bg-glow--1 {
    width: 500px;
    height: 500px;
    background: var(--c-primary-glow);
    top: -120px;
    right: -60px;
    animation: f 14s ease-in-out infinite
}

.bg-glow--2 {
    width: 400px;
    height: 400px;
    background: var(--c-accent-glow);
    bottom: -80px;
    left: -60px;
    animation: f 18s ease-in-out infinite reverse
}

@keyframes f {

    0%,
    100% {
        transform: translate(0, 0)
    }

    50% {
        transform: translate(25px, -20px)
    }
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 1
}

.hidden {
    display: none !important
}

.header {
    padding: 16px 0 8px
}

.header__row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px
}

.header__brand {
    display: flex;
    align-items: center;
    gap: 10px
}

.header__icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
    color: #fff
}

.header__title {
    font-size: 1.3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text
}

.header__nav {
    display: flex;
    align-items: center;
    gap: 10px
}

.challenge-label {
    font-size: .82rem;
    font-weight: 600;
    color: var(--c-text-sec);
    min-width: 50px;
    text-align: center
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border: none;
    border-radius: var(--radius-full);
    font-family: var(--font);
    font-size: .78rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    outline: none
}

.btn:focus-visible {
    outline: 2px solid var(--c-primary);
    outline-offset: 2px
}

.btn--primary {
    background: var(--c-primary);
    color: #fff
}

.btn--primary:hover {
    background: #5558E6
}

.btn--accent {
    background: rgba(34, 211, 238, .12);
    color: var(--c-accent);
    border: 1px solid rgba(34, 211, 238, .25)
}

.btn--accent:hover {
    background: rgba(34, 211, 238, .2)
}

.btn--ghost {
    background: transparent;
    color: var(--c-text-sec);
    border: 1px solid var(--c-border)
}

.btn--ghost:hover {
    background: var(--c-surface);
    color: var(--c-text)
}

.btn--danger {
    background: rgba(239, 68, 68, .12);
    color: var(--c-danger);
    border: 1px solid rgba(239, 68, 68, .2)
}

.btn--sm {
    padding: 6px 12px;
    font-size: .72rem
}

.btn:disabled {
    opacity: .4;
    cursor: not-allowed
}

.challenge-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 8px;
    margin: 12px 0
}

.challenge-bar__info {
    display: flex;
    align-items: center;
    gap: 8px
}

.challenge-bar__title {
    font-size: .95rem;
    font-weight: 700
}

.challenge-bar__actions {
    display: flex;
    gap: 6px
}

.difficulty-badge {
    font-size: .65rem;
    font-weight: 700;
    padding: 2px 10px;
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: .05em
}

.difficulty-badge--beginner {
    background: rgba(16, 185, 129, .1);
    color: var(--c-success)
}

.difficulty-badge--intermediate {
    background: rgba(245, 158, 11, .1);
    color: var(--c-warning)
}

.difficulty-badge--advanced {
    background: rgba(239, 68, 68, .1);
    color: var(--c-danger)
}

.split-view {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin-bottom: 16px
}

.panel {
    background: var(--c-bg-card);
    border: 1px solid var(--c-border);
    border-radius: var(--radius);
    padding: 16px;
    backdrop-filter: blur(16px)
}

.panel__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 10px
}

.panel__label {
    font-size: .78rem;
    font-weight: 600;
    color: var(--c-text-sec)
}

.canvas-frame {
    position: relative;
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: #F5F5F5
}

.canvas {
    width: 400px;
    height: 300px;
    max-width: 100%;
    margin: 0 auto;
    position: relative
}

.output-iframe {
    width: 400px;
    height: 300px;
    border: none;
    max-width: 100%;
    display: block
}

.overlay {
    position: absolute;
    inset: 0;
    opacity: .5;
    pointer-events: none;
    mix-blend-mode: difference;
    background: #fff
}

.score-info {
    display: flex;
    gap: 10px;
    align-items: center
}

.char-count {
    font-family: var(--font-mono);
    font-size: .75rem;
    color: var(--c-text-muted)
}

.accuracy {
    font-family: var(--font-mono);
    font-size: .82rem;
    font-weight: 700;
    color: var(--c-success)
}

.editor-section {
    background: var(--c-bg-card);
    border: 1px solid var(--c-border);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 16px;
    backdrop-filter: blur(16px)
}

.editor-section__header {
    margin-bottom: 10px
}

.css-editor {
    width: 100%;
    min-height: 200px;
    padding: 16px;
    border: 1px solid var(--c-border);
    border-radius: var(--radius-sm);
    background: #0D1117;
    color: #C9D1D9;
    font-family: var(--font-mono);
    font-size: .82rem;
    line-height: 1.7;
    resize: vertical;
    outline: none;
    transition: border-color var(--transition);
    tab-size: 2
}

.css-editor:focus {
    border-color: var(--c-primary)
}

.modal {
    position: fixed;
    inset: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center
}

.modal__backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, .6);
    backdrop-filter: blur(4px)
}

.modal__content {
    position: relative;
    background: #1E293B;
    border: 1px solid var(--c-border);
    border-radius: var(--radius);
    padding: 24px;
    width: 90%;
    max-width: 500px
}

.modal__title {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 12px
}

.modal__body {
    font-size: .85rem;
    color: var(--c-text-sec);
    line-height: 1.7;
    margin-bottom: 16px
}

.modal__body code {
    font-family: var(--font-mono);
    background: rgba(99, 102, 241, .12);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: .8rem;
    color: var(--c-accent)
}

.toast {
    position: fixed;
    bottom: 24px;
    right: 24px;
    padding: 10px 20px;
    background: var(--c-primary);
    color: #fff;
    border-radius: var(--radius-full);
    font-size: .82rem;
    font-weight: 500;
    z-index: 1000;
    animation: ti .3s ease, to .3s ease 1.7s forwards
}

@keyframes ti {
    from {
        opacity: 0;
        transform: translateY(10px)
    }

    to {
        opacity: 1;
        transform: translateY(0)
    }
}

@keyframes to {
    from {
        opacity: 1
    }

    to {
        opacity: 0;
        transform: translateY(10px)
    }
}

.footer {
    text-align: center;
    padding: 24px 0;
    border-top: 1px solid var(--c-border);
    color: var(--c-text-muted);
    font-size: .8rem;
    margin-top: 16px
}

@media(max-width:768px) {
    .split-view {
        grid-template-columns: 1fr
    }

    .canvas,
    .output-iframe {
        width: 100%;
        height: 250px
    }
}