:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --transition-speed: 0.3s;
    --net-bit-color: #ef4444;
    --host-bit-color: #3b82f6;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.5);
}

[data-theme="dark"] {
    --primary-color: #6366f1;
    --primary-hover: #818cf8;
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f8fafc;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --net-bit-color: #f87171;
    --host-bit-color: #60a5fa;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color var(--transition-speed), color var(--transition-speed);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-image: 
        radial-gradient(at 0% 0%, rgba(99, 102, 241, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(239, 68, 68, 0.1) 0px, transparent 50%);
    background-attachment: fixed;
}

/* Toast Notifications */
#toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 10000;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    background-color: var(--card-bg);
    color: var(--text-color);
    padding: 1rem 1.5rem;
    border-radius: 0.75rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.2);
    border-left: 4px solid var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 300px;
    transform: translateX(120%);
    transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    font-weight: 500;
}

.toast.show {
    transform: translateX(0);
}

.toast.error { border-left-color: #ef4444; }
.toast.success { border-left-color: #22c55e; }
.toast i { font-size: 1.2rem; }
.toast.error i { color: #ef4444; }
.toast.success i { color: #22c55e; }

/* Preloader */
#preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: opacity 0.5s ease;
}

.loader {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* App Container */
.app-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem;
    width: 100%;
    flex: 1;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo span { color: var(--primary-color); }
.badge {
    background: linear-gradient(135deg, #ff0080, #7928ca);
    color: white;
    font-size: 0.7rem;
    padding: 0.2rem 0.6rem;
    border-radius: 0.3rem;
    margin-left: 0.5rem;
    vertical-align: middle;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

.theme-btn {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    font-size: 1.1rem;
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-btn:hover {
    background-color: var(--border-color);
    transform: rotate(15deg);
}

/* Input Section */
.input-section {
    text-align: center;
    margin-bottom: 3rem;
}

.input-section h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(to right, var(--primary-color), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
}

.input-section p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.input-wrapper {
    max-width: 600px;
    margin: 0 auto;
}

.input-group {
    display: flex;
    background-color: var(--card-bg);
    padding: 0.5rem;
    border-radius: 1rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    position: relative;
    transition: transform 0.2s, box-shadow 0.2s;
}

.input-group:focus-within {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
    border-color: var(--primary-color);
}

.input-icon {
    position: absolute;
    left: 1.2rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    pointer-events: none;
}

#ip-input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 1rem 1rem 1rem 2.5rem;
    font-size: 1.1rem;
    color: var(--text-color);
    outline: none;
    font-family: 'Fira Code', monospace;
}

#calculate-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0 2rem;
    border-radius: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

#calculate-btn:hover { background-color: var(--primary-hover); }
#calculate-btn:active { transform: scale(0.98); }

.suggestions {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.chip {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 0.3rem 0.8rem;
    border-radius: 2rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s;
}

.chip:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Results Section */
.results-section {
    opacity: 1;
    transition: opacity 0.5s ease;
}

.results-section.hidden {
    display: none;
    opacity: 0;
}

.progress-container {
    width: 100%;
    height: 4px;
    background-color: var(--border-color);
    border-radius: 2px;
    margin-bottom: 2rem;
    overflow: hidden;
    display: none;
}

.progress-bar {
    height: 100%;
    background-color: var(--primary-color);
    width: 0%;
    transition: width 0.5s ease;
}

/* Cards Grid */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.card {
    background-color: var(--glass-bg);
    backdrop-filter: blur(10px);
    padding: 1.5rem;
    border-radius: 1rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--glass-border);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.5s forwards;
    position: relative;
    overflow: hidden;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px -5px rgba(0, 0, 0, 0.1);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
}

.card-header i { color: var(--primary-color); }

.card p {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-color);
    font-family: 'Fira Code', monospace;
    word-break: break-all;
}

.math-detail {
    display: block;
    margin-top: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-family: 'Fira Code', monospace;
}

.copyable { cursor: pointer; }
.copyable:active { opacity: 0.7; }

/* Details Grid */
.details-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.5s forwards;
}

.detail-card {
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.detail-card h3 {
    font-size: 1.1rem;
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.info-row {
    display: flex;
    justify-content: space-between;
    padding: 0.6rem 0;
    border-bottom: 1px dashed var(--border-color);
}

.info-row:last-child { border-bottom: none; }
.info-row span { color: var(--text-secondary); font-size: 0.95rem; }
.info-row strong { color: var(--text-color); font-weight: 600; }
.font-mono { font-family: 'Fira Code', monospace; }

/* Binary Visualization */
.binary-container {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.5s forwards;
}

.binary-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.binary-row-group {
    margin-bottom: 1.5rem;
}

.bin-label {
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

.bin-visual {
    font-family: 'Fira Code', monospace;
    font-size: 1.1rem;
    letter-spacing: 0;
    display: flex;
    flex-wrap: wrap;
    gap: 10px; /* Gap between octets */
}

.octet-group {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.bits-row {
    display: flex;
    gap: 2px;
}

.decimal-row {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 4px;
    font-weight: 500;
}

.bit {
    display: inline-block;
    width: 12px;
    text-align: center;
}

.bit.net { color: var(--net-bit-color); font-weight: 700; }
.bit.host { color: var(--host-bit-color); }

.dot {
    display: inline-block;
    width: 12px;
    text-align: center;
    color: var(--text-secondary);
}

/* Footer */
footer {
    text-align: center;
    margin-top: auto;
    padding-top: 2rem;
    padding-bottom: 1rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.footer-link {
    color: var(--text-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    transition: color 0.2s;
}

.footer-link:hover {
    color: var(--primary-color);
}

.rgb-text {
    background: linear-gradient(to right, #a855f7, #ec4899, #8b5cf6, #a855f7);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    animation: rainbow 4s linear infinite;
    background-size: 300% auto;
    font-weight: 700;
    font-size: 1rem;
}

@keyframes rainbow {
    0% { background-position: 0% 50%; }
    100% { background-position: 100% 50%; }
}

/* Animations */
@keyframes fadeInUp {
    to { opacity: 1; transform: translateY(0); }
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }
.delay-5 { animation-delay: 0.5s; }
.delay-6 { animation-delay: 0.6s; }

/* Responsive */
@media (max-width: 600px) {
    .app-container { 
        padding: 1rem; 
    }

    .input-section h1 { 
        font-size: 1.5rem; 
        margin-bottom: 0.5rem;
    }

    .input-section p {
        font-size: 0.9rem;
        margin-bottom: 1.5rem;
    }

    .input-group { 
        flex-direction: column; 
        padding: 0.75rem; 
        gap: 0.75rem;
    }

    /* Fix Icon Position for Mobile */
    .input-icon {
        top: 2.15rem; /* Aligns with input field center */
        left: 1.2rem;
        transform: translateY(-50%);
    }

    #ip-input {
        width: 100%;
        padding: 0.8rem 0.8rem 0.8rem 2.5rem;
        font-size: 1rem;
        background-color: var(--bg-color); /* Slight contrast */
        border-radius: 0.5rem;
    }

    #calculate-btn { 
        width: 100%; 
        justify-content: center; 
        padding: 0.9rem; 
        margin-top: 0;
        font-size: 1rem;
    }

    .suggestions {
        justify-content: center;
        gap: 0.4rem;
    }

    .chip {
        font-size: 0.75rem;
        padding: 0.25rem 0.6rem;
    }

    /* Grid Adjustments */
    .cards-grid {
        grid-template-columns: 1fr; /* Full width cards */
        gap: 1rem;
    }

    .details-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    /* Binary Visualization Mobile */
    .bin-visual { 
        font-size: 0.8rem; 
        justify-content: center;
        gap: 4px;
    }

    .octet-group {
        margin: 2px;
    }

    .bit { width: 7px; }
    .dot { width: 7px; }
    
    .decimal-row {
        font-size: 0.65rem;
    }
}