@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600;700&display=swap');

:root {
    --color-bg: #0b0e17;
    --color-surface: rgba(255, 255, 255, 0.04);
    --color-surface-hover: rgba(255, 255, 255, 0.07);
    --color-surface-solid: #141825;
    --color-text: #e4e8f1;
    --color-text-muted: #7a8299;
    --color-border: rgba(255, 255, 255, 0.08);
    --color-border-focus: rgba(99, 102, 241, 0.5);
    --color-primary: #6366f1;
    --color-primary-hover: #818cf8;
    --color-primary-glow: rgba(99, 102, 241, 0.25);
    --color-secondary: #06b6d4;
    --color-secondary-glow: rgba(6, 182, 212, 0.2);
    --color-success: #10b981;
    --color-success-glow: rgba(16, 185, 129, 0.2);
    --color-danger: #f43f5e;
    --color-danger-glow: rgba(244, 63, 94, 0.2);
    --color-warning: #f59e0b;
    --color-accent: #a78bfa;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-2xl: 24px;

    --space-1: 4px;
    --space-2: 8px;
    --space-3: 12px;
    --space-4: 16px;
    --space-5: 20px;
    --space-6: 24px;
    --space-8: 32px;
    --space-10: 40px;
    --space-12: 48px;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 30px var(--color-primary-glow);

    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'SF Mono', 'Consolas', monospace;

    --glass-bg: rgba(20, 24, 37, 0.6);
    --glass-border: rgba(255, 255, 255, 0.06);
    --glass-blur: blur(20px);
}

/* ==============================
   ANIMATED BACKGROUND
   ============================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    padding: var(--space-5);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 60% at 20% 10%, rgba(99, 102, 241, 0.15) 0%, transparent 60%),
        radial-gradient(ellipse 60% 40% at 80% 80%, rgba(6, 182, 212, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse 50% 50% at 50% 50%, rgba(167, 139, 250, 0.08) 0%, transparent 60%);
    animation: meshShift 20s ease-in-out infinite alternate;
    pointer-events: none;
    z-index: 0;
}

@keyframes meshShift {
    0% {
        background:
            radial-gradient(ellipse 80% 60% at 20% 10%, rgba(99, 102, 241, 0.15) 0%, transparent 60%),
            radial-gradient(ellipse 60% 40% at 80% 80%, rgba(6, 182, 212, 0.12) 0%, transparent 50%),
            radial-gradient(ellipse 50% 50% at 50% 50%, rgba(167, 139, 250, 0.08) 0%, transparent 60%);
    }
    33% {
        background:
            radial-gradient(ellipse 70% 50% at 70% 20%, rgba(6, 182, 212, 0.18) 0%, transparent 60%),
            radial-gradient(ellipse 50% 60% at 20% 70%, rgba(99, 102, 241, 0.12) 0%, transparent 50%),
            radial-gradient(ellipse 60% 40% at 60% 60%, rgba(244, 63, 94, 0.06) 0%, transparent 60%);
    }
    66% {
        background:
            radial-gradient(ellipse 60% 70% at 40% 80%, rgba(167, 139, 250, 0.15) 0%, transparent 60%),
            radial-gradient(ellipse 80% 40% at 70% 10%, rgba(16, 185, 129, 0.1) 0%, transparent 50%),
            radial-gradient(ellipse 40% 50% at 30% 30%, rgba(99, 102, 241, 0.1) 0%, transparent 60%);
    }
    100% {
        background:
            radial-gradient(ellipse 80% 60% at 50% 30%, rgba(99, 102, 241, 0.12) 0%, transparent 60%),
            radial-gradient(ellipse 60% 50% at 10% 60%, rgba(6, 182, 212, 0.15) 0%, transparent 50%),
            radial-gradient(ellipse 50% 60% at 80% 40%, rgba(167, 139, 250, 0.1) 0%, transparent 60%);
    }
}

/* ==============================
   GLASS CONTAINER
   ============================== */
.container {
    max-width: 1060px;
    width: 100%;
    margin: 0 auto;
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-xl), inset 0 1px 0 rgba(255,255,255,0.04);
    padding: var(--space-8);
    flex: 1;
    margin-bottom: 80px;
    position: relative;
    z-index: 1;
    animation: containerFadeIn 0.6s ease-out;
}

@keyframes containerFadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ==============================
   HEADER
   ============================== */
.header-wrapper {
    text-align: center;
    margin-bottom: var(--space-8);
}

h1 {
    text-align: center;
    color: var(--color-text);
    margin-bottom: var(--space-2);
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 800;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, #e4e8f1 0%, #a78bfa 50%, #6366f1 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.9rem;
    margin-bottom: var(--space-8);
    font-weight: 400;
}

/* ==============================
   XP / LEVEL BAR
   ============================== */
.xp-bar-wrapper {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    margin-bottom: var(--space-6);
    padding: var(--space-3) var(--space-5);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    backdrop-filter: var(--glass-blur);
}

.xp-level-badge {
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-radius: var(--radius-md);
    font-weight: 800;
    font-size: 1.1rem;
    color: #fff;
    box-shadow: 0 0 20px var(--color-primary-glow);
    flex-shrink: 0;
}

.xp-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.xp-label {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    display: flex;
    justify-content: space-between;
}

.xp-track {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 4px;
    overflow: hidden;
    position: relative;
}

.xp-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    border-radius: 4px;
    transition: width 0.8s cubic-bezier(0.22, 1, 0.36, 1);
    position: relative;
}

.xp-fill::after {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 20px;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3));
    border-radius: 4px;
}

/* ==============================
   STATS BAR
   ============================== */
.stats-bar {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-3);
    margin-bottom: var(--space-6);
}

.stat-item {
    text-align: center;
    padding: var(--space-4) var(--space-3);
    border-radius: var(--radius-lg);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    backdrop-filter: var(--glass-blur);
    transition: transform 0.2s ease, border-color 0.3s ease;
    position: relative;
    overflow: hidden;
}

.stat-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--color-primary), transparent);
    opacity: 0;
    transition: opacity 0.3s;
}

.stat-item:hover {
    transform: translateY(-2px);
    border-color: rgba(99, 102, 241, 0.2);
}

.stat-item:hover::before {
    opacity: 1;
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--color-primary-hover);
    font-family: var(--font-mono);
    transition: transform 0.3s ease;
}

.stat-label {
    font-size: 0.7rem;
    color: var(--color-text-muted);
    margin-top: var(--space-1);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
}

.streak {
    color: var(--color-danger) !important;
}

.timer {
    color: var(--color-secondary) !important;
}

/* ==============================
   DIFFICULTY SELECTOR
   ============================== */
.difficulty-selector {
    display: flex;
    gap: 2px;
    justify-content: center;
    margin-bottom: var(--space-6);
    padding: 3px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    width: fit-content;
    margin-left: auto;
    margin-right: auto;
    border: 1px solid var(--color-border);
    position: relative;
}

.difficulty-btn {
    padding: var(--space-2) var(--space-6);
    border: none;
    background: transparent;
    color: var(--color-text-muted);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.22, 1, 0.36, 1);
    font-size: 0.85rem;
    font-weight: 600;
    font-family: var(--font-sans);
    position: relative;
    z-index: 1;
}

.difficulty-btn.active {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: white;
    box-shadow: 0 4px 15px var(--color-primary-glow);
}

.difficulty-btn:hover:not(.active) {
    color: var(--color-text);
    background: rgba(255, 255, 255, 0.04);
}

/* ==============================
   ADVANCED PANEL
   ============================== */
.advanced-panel {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    margin-bottom: var(--space-6);
    border: 1px solid var(--color-border);
    backdrop-filter: var(--glass-blur);
    transition: border-color 0.3s;
}

.advanced-panel:hover {
    border-color: rgba(255, 255, 255, 0.1);
}

.advanced-panel h3 {
    margin-bottom: var(--space-4);
    color: var(--color-text);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 0.95rem;
    user-select: none;
    transition: color 0.2s;
}

.advanced-panel h3:hover {
    color: var(--color-primary-hover);
}

.advanced-content {
    display: none;
    gap: var(--space-4);
    flex-direction: column;
}

.advanced-content.visible {
    display: flex;
    animation: slideDown 0.3s ease;
}

.option-row {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    flex-wrap: wrap;
}

.option-row label {
    font-size: 0.875rem;
    color: var(--color-text-muted);
}

select {
    padding: var(--space-2) var(--space-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    background: var(--color-surface-solid);
    color: var(--color-text);
    font-family: var(--font-sans);
    cursor: pointer;
    outline: none;
    transition: border-color 0.2s;
}

select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
}

/* ==============================
   TARGET IP SECTION
   ============================== */
.target-section {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.2) 0%, rgba(6, 182, 212, 0.15) 50%, rgba(167, 139, 250, 0.2) 100%);
    border: 1px solid rgba(99, 102, 241, 0.2);
    padding: var(--space-8) var(--space-6);
    border-radius: var(--radius-xl);
    margin-bottom: var(--space-6);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.target-section::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(ellipse at center, rgba(99, 102, 241, 0.06) 0%, transparent 70%);
    animation: targetPulse 6s ease-in-out infinite;
    pointer-events: none;
}

@keyframes targetPulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.1); opacity: 1; }
}

.target-section h2 {
    color: var(--color-text-muted);
    font-size: 0.7rem;
    margin-bottom: var(--space-3);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    position: relative;
    z-index: 1;
}

.target-ip-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    margin-bottom: var(--space-5);
    position: relative;
    z-index: 1;
}

.target-ip {
    font-size: clamp(1.8rem, 5vw, 2.75rem);
    color: #fff;
    font-weight: 700;
    font-family: var(--font-mono);
    letter-spacing: 0.02em;
    text-shadow: 0 0 40px var(--color-primary-glow);
}

.copy-btn {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: white;
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 1rem;
    backdrop-filter: blur(10px);
}

.copy-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: scale(1.05);
}

/* ==============================
   BUTTONS
   ============================== */
.btn {
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    font-family: var(--font-sans);
    transition: all 0.25s cubic-bezier(0.22, 1, 0.36, 1);
    border: none;
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
    transition: left 0.5s ease;
}

.btn:hover::after {
    left: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, #fff, #e4e8f1);
    color: var(--color-primary);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.1);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(255, 255, 255, 0.15);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.08);
    color: rgba(255, 255, 255, 0.9);
    border: 1px solid rgba(255, 255, 255, 0.12);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-1px);
}

.btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    transform: none !important;
}

.btn:disabled::after {
    display: none;
}

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

/* ==============================
   HINT & STEPS PANELS
   ============================== */
.hint-box, .steps-panel {
    padding: var(--space-4) var(--space-5);
    margin: var(--space-4) 0;
    border-radius: var(--radius-lg);
    display: none;
    border-left: 3px solid;
    backdrop-filter: var(--glass-blur);
}

.hint-box {
    background: rgba(245, 158, 11, 0.08);
    border-color: var(--color-warning);
    color: var(--color-text);
}

.steps-panel {
    background: rgba(6, 182, 212, 0.08);
    border-color: var(--color-secondary);
    color: var(--color-text);
}

.hint-box.visible, .steps-panel.visible {
    display: block;
    animation: slideDown 0.3s ease;
}

.step-item {
    margin: var(--space-2) 0;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--color-text);
}

@keyframes slideDown {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ==============================
   PROGRESS BAR
   ============================== */
.progress-bar-wrapper {
    margin-bottom: var(--space-5);
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.progress-label {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    white-space: nowrap;
}

.progress-track {
    flex: 1;
    height: 6px;
    background: rgba(255, 255, 255, 0.06);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--color-success), var(--color-secondary));
    border-radius: 3px;
    width: 0%;
    transition: width 0.5s cubic-bezier(0.22, 1, 0.36, 1);
}

.progress-count {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    font-family: var(--font-mono);
    font-weight: 600;
    min-width: 32px;
    text-align: right;
}

/* ==============================
   BINARY VISUALIZATION
   ============================== */
.binary-viz {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    margin-bottom: var(--space-6);
    display: none;
    backdrop-filter: var(--glass-blur);
    overflow-x: auto;
}

.binary-viz.visible {
    display: block;
    animation: slideDown 0.3s ease;
}

.binary-viz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-4);
}

.binary-viz-header h3 {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.binary-row {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    margin-bottom: var(--space-2);
    font-family: var(--font-mono);
    font-size: 0.8rem;
}

.binary-label {
    min-width: 90px;
    color: var(--color-text-muted);
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.binary-bits {
    display: flex;
    gap: 1px;
    flex-wrap: wrap;
}

.binary-bits .network-bit {
    color: var(--color-primary-hover);
    font-weight: 700;
}

.binary-bits .host-bit {
    color: var(--color-secondary);
    font-weight: 500;
    opacity: 0.7;
}

.binary-bits .dot-sep {
    color: var(--color-text-muted);
    margin: 0 3px;
}

/* ==============================
   CHEAT SHEET
   ============================== */
.cheat-sheet {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    margin-bottom: var(--space-6);
    backdrop-filter: var(--glass-blur);
    transition: border-color 0.3s;
}

.cheat-sheet:hover {
    border-color: rgba(255, 255, 255, 0.1);
}

.cheat-sheet-header {
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--color-text);
    user-select: none;
    transition: color 0.2s;
}

.cheat-sheet-header:hover {
    color: var(--color-primary-hover);
}

.cheat-sheet-content {
    display: none;
    margin-top: var(--space-4);
}

.cheat-sheet-content.visible {
    display: block;
    animation: slideDown 0.3s ease;
}

.cheat-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: var(--radius-md);
    overflow: hidden;
    font-size: 0.8rem;
    font-family: var(--font-mono);
}

.cheat-table th {
    background: rgba(99, 102, 241, 0.1);
    color: var(--color-primary-hover);
    font-weight: 700;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    padding: var(--space-3);
    border-bottom: 1px solid var(--color-border);
    text-align: left;
}

.cheat-table td {
    padding: var(--space-2) var(--space-3);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text);
    background: transparent;
}

.cheat-table tbody tr:last-child td {
    border-bottom: none;
}

.cheat-table tbody tr:hover td {
    background: rgba(255, 255, 255, 0.02);
}

/* ==============================
   TABLE (DESKTOP)
   ============================== */
.table-wrapper {
    display: block;
    margin-bottom: var(--space-6);
}

table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 1px solid var(--color-border);
}

th, td {
    padding: var(--space-4);
    text-align: left;
}

th {
    background: rgba(99, 102, 241, 0.06);
    color: var(--color-text-muted);
    font-weight: 700;
    font-size: 0.7rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    border-bottom: 1px solid var(--color-border);
}

td {
    color: var(--color-text);
    background: transparent;
    border-bottom: 1px solid var(--color-border);
}

tbody tr {
    transition: background 0.15s;
}

tbody tr:hover {
    background: rgba(255, 255, 255, 0.02);
}

tbody tr:last-child td {
    border-bottom: none;
}

/* ==============================
   INPUTS
   ============================== */
input[type="text"] {
    width: 100%;
    padding: var(--space-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-family: var(--font-mono);
    transition: all 0.3s cubic-bezier(0.22, 1, 0.36, 1);
    background: var(--color-surface-solid);
    color: var(--color-text);
    outline: none;
}

input[type="text"]::placeholder {
    color: rgba(122, 130, 153, 0.5);
}

input[type="text"]:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow), 0 0 20px var(--color-primary-glow);
}

input[type="text"].correct-input {
    border-color: var(--color-success);
    box-shadow: 0 0 0 3px var(--color-success-glow), 0 0 15px var(--color-success-glow);
}

input[type="text"].incorrect {
    border-color: var(--color-danger);
    box-shadow: 0 0 0 3px var(--color-danger-glow), 0 0 15px var(--color-danger-glow);
    animation: inputShake 0.4s ease;
}

@keyframes inputShake {
    0%, 100% { transform: translateX(0); }
    20% { transform: translateX(-4px); }
    40% { transform: translateX(4px); }
    60% { transform: translateX(-3px); }
    80% { transform: translateX(3px); }
}

.status {
    text-align: center;
    font-size: 1.25rem;
    min-width: 32px;
}

.correct {
    color: var(--color-success);
    text-shadow: 0 0 10px var(--color-success-glow);
}

.incorrect {
    color: var(--color-danger);
    text-shadow: 0 0 10px var(--color-danger-glow);
}

.answer {
    font-family: var(--font-mono);
    color: var(--color-primary-hover);
    font-weight: 600;
}

.answer-cell {
    opacity: 0;
    transition: opacity 0.3s;
}

.answer-cell.visible {
    opacity: 1;
}

.show-btn {
    background: rgba(99, 102, 241, 0.1);
    color: var(--color-primary-hover);
    border: 1px solid rgba(99, 102, 241, 0.2);
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.8rem;
    font-weight: 600;
    font-family: var(--font-sans);
    transition: all 0.2s;
}

.show-btn:hover {
    background: rgba(99, 102, 241, 0.2);
    transform: translateY(-1px);
}

.show-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: none !important;
}

.error-msg {
    color: var(--color-danger);
    font-size: 0.75rem;
    margin-top: var(--space-1);
}

/* ==============================
   CONTROLS
   ============================== */
.controls {
    display: flex;
    gap: var(--space-3);
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    margin-top: var(--space-6);
}

.controls .btn {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: white;
    box-shadow: 0 4px 15px var(--color-primary-glow);
}

.controls .btn:hover {
    box-shadow: 0 6px 25px var(--color-primary-glow);
    transform: translateY(-2px);
}

.checkbox-group, .dark-mode-toggle {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    background: var(--color-surface);
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    transition: border-color 0.2s;
}

.checkbox-group:hover, .dark-mode-toggle:hover {
    border-color: rgba(255, 255, 255, 0.12);
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--color-primary);
}

.checkbox-group label, .dark-mode-toggle span {
    cursor: pointer;
    color: var(--color-text);
    font-size: 0.85rem;
    font-weight: 500;
}

/* Toggle Switch */
.toggle-switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}

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

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.1);
    transition: 0.3s cubic-bezier(0.22, 1, 0.36, 1);
    border-radius: 24px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: #fff;
    transition: 0.3s cubic-bezier(0.22, 1, 0.36, 1);
    border-radius: 50%;
}

input:checked + .slider {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    box-shadow: 0 0 15px var(--color-primary-glow);
}

input:checked + .slider:before {
    transform: translateX(20px);
}

/* ==============================
   KEYBOARD SHORTCUTS LEGEND
   ============================== */
.shortcuts-btn {
    position: fixed;
    bottom: var(--space-5);
    right: var(--space-5);
    width: 44px;
    height: 44px;
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: 50%;
    color: var(--color-text-muted);
    font-size: 1.1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
    z-index: 90;
    box-shadow: var(--shadow-lg);
}

.shortcuts-btn:hover {
    color: var(--color-primary-hover);
    border-color: rgba(99, 102, 241, 0.3);
    transform: scale(1.1);
}

.shortcuts-tooltip {
    position: fixed;
    bottom: 70px;
    right: var(--space-5);
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--space-4) var(--space-5);
    z-index: 91;
    box-shadow: var(--shadow-xl);
    display: none;
    min-width: 200px;
}

.shortcuts-tooltip.visible {
    display: block;
    animation: slideDown 0.25s ease;
}

.shortcuts-tooltip h4 {
    font-size: 0.8rem;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: var(--space-3);
    font-weight: 700;
}

.shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-1) 0;
    font-size: 0.82rem;
}

.shortcut-item span:first-child {
    color: var(--color-text-muted);
}

.shortcut-key {
    background: rgba(99, 102, 241, 0.15);
    color: var(--color-primary-hover);
    padding: 2px 8px;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 600;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

/* ==============================
   STATS VIEW
   ============================== */
.stats-view {
    background: var(--color-surface);
    padding: var(--space-5);
    border-radius: var(--radius-lg);
    margin: var(--space-4) 0;
    border: 1px solid var(--color-border);
    backdrop-filter: var(--glass-blur);
}

.stats-view table {
    margin: 0;
}

/* ==============================
   TOAST
   ============================== */
.toast {
    position: fixed;
    top: var(--space-5);
    right: var(--space-5);
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    color: var(--color-text);
    padding: var(--space-4) var(--space-5);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    border: 1px solid var(--glass-border);
    opacity: 0;
    transform: translateY(-20px) scale(0.95);
    pointer-events: none;
    transition: all 0.4s cubic-bezier(0.22, 1, 0.36, 1);
    z-index: 1000;
    max-width: 340px;
    font-weight: 500;
}

.toast.show {
    opacity: 1;
    transform: translateY(0) scale(1);
    pointer-events: auto;
}

.toast.success {
    border-left: 3px solid var(--color-success);
    box-shadow: var(--shadow-xl), -4px 0 20px var(--color-success-glow);
}

.toast.error {
    border-left: 3px solid var(--color-danger);
    box-shadow: var(--shadow-xl), -4px 0 20px var(--color-danger-glow);
}

/* ==============================
   CONFETTI
   ============================== */
.confetti-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.confetti-piece {
    position: absolute;
    width: 8px;
    height: 12px;
    top: -20px;
    border-radius: 2px;
    animation: confettiFall 2.5s ease-in forwards;
}

@keyframes confettiFall {
    0% {
        top: -5%;
        transform: rotateZ(0deg) rotateY(0deg);
        opacity: 1;
    }
    100% {
        top: 100%;
        transform: rotateZ(720deg) rotateY(360deg);
        opacity: 0;
    }
}

/* ==============================
   FOOTER
   ============================== */
footer {
    text-align: center;
    color: var(--color-text-muted);
    font-size: 0.8rem;
    margin-top: var(--space-6);
    padding: var(--space-4);
    position: relative;
    z-index: 1;
}

footer a {
    color: var(--color-primary-hover);
    text-decoration: none;
    transition: all 0.2s;
    font-weight: 500;
}

footer a:hover {
    color: var(--color-accent);
    text-decoration: underline;
}

/* ==============================
   MOBILE CARD LAYOUT
   ============================== */
.card-layout {
    display: none;
}

.field-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-4);
    margin-bottom: var(--space-3);
    backdrop-filter: var(--glass-blur);
    transition: border-color 0.2s;
}

.field-card:hover {
    border-color: rgba(255, 255, 255, 0.1);
}

.field-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-3);
}

.field-card-label {
    font-weight: 700;
    color: var(--color-text);
    font-size: 0.875rem;
}

.field-card-body {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.field-card-input-row {
    display: flex;
    gap: var(--space-2);
    align-items: flex-start;
}

.field-card-input-row input {
    flex: 1;
}

.field-card-answer {
    font-family: var(--font-mono);
    color: var(--color-primary-hover);
    font-size: 0.85rem;
    padding: var(--space-2) var(--space-3);
    background: rgba(99, 102, 241, 0.08);
    border-radius: var(--radius-sm);
    display: none;
}

.field-card-answer.visible {
    display: block;
}

/* ==============================
   STICKY ACTION BAR (MOBILE)
   ============================== */
.sticky-action-bar {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    border-top: 1px solid var(--glass-border);
    padding: var(--space-3);
    box-shadow: 0 -8px 30px rgba(0, 0, 0, 0.4);
    z-index: 100;
    gap: var(--space-2);
    justify-content: center;
}

.sticky-action-bar .btn {
    flex: 1;
    max-width: 150px;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: #fff;
}

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

*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* ==============================
   RESPONSIVE (<= 820px)
   ============================== */
@media (max-width: 820px) {
    body {
        padding: var(--space-3);
    }

    .container {
        padding: var(--space-5);
        margin-bottom: 100px;
    }

    h1 {
        font-size: 1.75rem;
    }

    .stats-bar {
        grid-template-columns: repeat(2, 1fr);
    }

    .difficulty-selector {
        width: 100%;
    }

    .target-section {
        padding: var(--space-5);
    }

    .target-ip-wrapper {
        flex-direction: column;
        gap: var(--space-2);
    }

    .table-wrapper {
        display: none;
    }

    .card-layout {
        display: block;
    }

    .sticky-action-bar {
        display: flex;
    }

    .controls {
        display: none;
    }

    .shortcuts-btn {
        display: none;
    }

    .advanced-panel {
        padding: var(--space-4);
    }

    .option-row {
        flex-direction: column;
        align-items: flex-start;
    }

    .checkbox-group, .dark-mode-toggle {
        width: 100%;
        justify-content: space-between;
    }

    .toast {
        right: var(--space-3);
        left: var(--space-3);
        max-width: none;
    }

    .binary-row {
        font-size: 0.7rem;
    }

    .binary-label {
        min-width: 70px;
        font-size: 0.65rem;
    }

    .xp-bar-wrapper {
        padding: var(--space-3);
    }
}

@media (max-width: 480px) {
    .stats-bar {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-2);
    }

    .stat-item {
        padding: var(--space-3);
    }

    .stat-value {
        font-size: 1.4rem;
    }

    .difficulty-btn {
        flex: 1;
        padding: var(--space-2) var(--space-3);
        font-size: 0.8rem;
    }

    .sticky-action-bar .btn {
        font-size: 0.8rem;
        padding: var(--space-2) var(--space-3);
    }

    footer {
        margin-bottom: var(--space-12);
        padding-bottom: var(--space-6);
    }

    .binary-bits {
        font-size: 0.65rem;
    }
}