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

:root {
    --bg-deep: #090b10;
    --bg-surface: #0f1219;
    --bg-card: #151a24;
    --bg-input: #1b212c;
    --accent-blue: #308cfc;
    --accent-blue-hover: #1d72d6;
    --accent-blue-glow: rgba(48, 140, 252, 0.2);
    --text-primary: #ffffff;
    --text-secondary: #94a3b8;
    --text-dim: #64748b;
    --border-color: #252d3d;
    --radius-xl: 32px;
    --radius-lg: 20px;
    --radius-md: 12px;
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --container-max: 1100px;
}

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

body {
    background-color: var(--bg-deep);
    color: var(--text-primary);
    min-height: 100vh;
}

/* Background Effects */
.background-blobs {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.blob {
    position: absolute;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.1;
}

.blob-1 {
    top: -10%;
    right: 10%;
    width: 600px;
    height: 600px;
    background: var(--accent-blue);
}

.blob-2 {
    bottom: -10%;
    left: 10%;
    width: 500px;
    height: 500px;
    background: #0047ab;
}

/* App Container (Web Dashboard Style) */
.app-container {
    max-width: var(--container-max);
    margin: 40px auto;
    background-color: var(--bg-surface);
    border-radius: var(--radius-xl);
    display: flex;
    flex-direction: column;
    min-height: 80vh;
    box-shadow: 0 40px 100px -20px rgba(0, 0, 0, 0.6);
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
}

header {
    padding: 40px 60px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -1px;
}

header .header-icon {
    background: var(--bg-card);
    padding: 12px;
    border-radius: var(--radius-md);
    color: var(--accent-blue);
    border: 1px solid var(--border-color);
}

/* Navigation Tabs (Web Style) */
.tabs {
    display: flex;
    padding: 0 60px;
    gap: 12px;
    border-bottom: 1px solid var(--border-color);
    background: rgba(0, 0, 0, 0.1);
}

.tab-btn {
    padding: 16px 24px;
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition);
}

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

.tab-btn.active {
    color: var(--accent-blue);
    border-bottom-color: var(--accent-blue);
}

/* Main Content Area */
main {
    flex: 1;
    padding: 40px 60px;
    display: flex;
    flex-direction: column;
}

.calc-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    animation: fadeIn 0.4s ease;
}

.calc-section.hidden {
    display: none;
}

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

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

/* Left side of grids: Controls */
.controls-panel {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Right side of grids: Result Card */
.result-panel {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    border: 1px solid var(--border-color);
    text-align: center;
    position: relative;
}

.result-panel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--accent-blue);
    border-radius: 4px 4px 0 0;
}

h2 {
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--accent-blue);
    margin-bottom: 24px;
    grid-column: span 2;
}

/* Input Styles */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.input-group label {
    font-size: 0.8rem;
    color: var(--text-dim);
    font-weight: 600;
    text-transform: uppercase;
}

input[type="number"],
input[type="text"],
select {
    width: 100%;
    background-color: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    color: var(--text-primary);
    font-size: 1rem;
    outline: none;
    transition: var(--transition);
}

input[type="number"]:focus,
select:focus {
    border-color: var(--accent-blue);
    background-color: #212836;
    box-shadow: 0 0 0 4px var(--accent-blue-glow);
}

/* Calculator Grid */
.grid-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-top: 10px;
}

.op-btn {
    height: 54px;
    border-radius: var(--radius-md);
    border: none;
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 1.25rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.op-btn:hover {
    background: #252d3d;
    transform: translateY(-2px);
}

.op-btn[data-action="add"],
.op-btn[data-action="sub"],
.op-btn[data-action="mul"],
.op-btn[data-action="div"] {
    background: rgba(48, 140, 252, 0.1);
    color: var(--accent-blue);
}

.primary-btn {
    background: var(--accent-blue);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: 18px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 10px 20px -5px var(--accent-blue-glow);
}

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

.btn-clear {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.2);
    border-radius: var(--radius-md);
    padding: 16px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.btn-clear:hover {
    background: rgba(239, 68, 68, 0.2);
}

.full-width {
    grid-column: span 4;
}

/* Result Visualization */
.result-group {
    width: 100%;
}

.result-group label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-dim);
    margin-bottom: 16px;
    font-weight: 600;
}

.result-group input {
    background: transparent !important;
    border: none !important;
    text-align: center;
    font-size: 3.5rem !important;
    font-weight: 800;
    color: var(--text-primary) !important;
    padding: 0 !important;
    height: auto !important;
}

.result-group input::placeholder {
    color: var(--bg-input);
}

/* Responsive Adjustments */
@media (max-width: 900px) {
    .app-container {
        margin: 20px;
        border-radius: var(--radius-lg);
    }

    .calc-section {
        grid-template-columns: 1fr;
    }

    header,
    .tabs,
    main {
        padding-left: 30px;
        padding-right: 30px;
    }

    h2 {
        grid-column: span 1;
    }
}

@media (max-width: 600px) {
    .tabs {
        overflow-x: auto;
    }

    .tab-btn {
        padding: 12px 16px;
    }
}