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

:root {
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --secondary: #06ffa5;
    --accent: #f72585;
    --danger: #dc2626;
    --warning: #f59e0b;
    --dark-bg: #0f172a;
    --dark-surface: #1e293b;
    --dark-surface-2: #334155;
    --light-bg: #f8fafc;
    --light-surface: #ffffff;
    --light-surface-2: #f1f5f9;
    --text-dark: #0f172a;
    --text-light: #f1f5f9;
    --text-muted-dark: #64748b;
    --text-muted-light: #94a3b8;
    --border-radius: 16px;
    --border-radius-sm: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --bg-primary: var(--dark-bg);
    --bg-secondary: var(--dark-surface);
    --bg-tertiary: var(--dark-surface-2);
    --text-primary: var(--text-light);
    --text-secondary: var(--text-muted-light);
    --border-color: rgba(255,255,255,0.08);
    --card-bg: var(--dark-surface);
    --input-bg: var(--dark-surface-2);
    --shadow: 0 8px 20px rgba(0,0,0,0.3);
}

[data-theme="light"] {
    --bg-primary: var(--light-bg);
    --bg-secondary: var(--light-surface);
    --bg-tertiary: var(--light-surface-2);
    --text-primary: var(--text-dark);
    --text-secondary: var(--text-muted-dark);
    --border-color: rgba(0,0,0,0.06);
    --card-bg: var(--light-surface);
    --input-bg: var(--light-surface-2);
    --shadow: 0 8px 30px rgba(0,0,0,0.08);
}

body {
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-primary) 100%);
    color: var(--text-primary);
    font-family: 'Plus Jakarta Sans', sans-serif;
    transition: var(--transition);
    line-height: 1.5;
    min-height: 100vh;
    padding: 24px;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 10% 20%, rgba(67,97,238,0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

.container {
    max-width: 620px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

/* প্রধান কার্ড */
.converter-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 28px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
    transition: var(--transition);
}

/* হেডার */
.header {
    text-align: center;
    margin-bottom: 28px;
}

.logo-wrapper {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    width: 70px;
    height: 70px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    box-shadow: 0 8px 20px rgba(67,97,238,0.3);
}

.logo-wrapper i {
    font-size: 34px;
    color: white;
}

h1 {
    font-size: 1.8rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
    letter-spacing: -0.5px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-top: 6px;
}

/* টুলবার */
.toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.mode-switch {
    display: flex;
    background: var(--bg-tertiary);
    border-radius: 40px;
    padding: 4px;
    flex: 1;
}

.mode-btn {
    flex: 1;
    padding: 8px 16px;
    border: none;
    background: transparent;
    border-radius: 40px;
    font-family: inherit;
    font-weight: 600;
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

.mode-btn.active {
    background: var(--primary);
    color: white;
    box-shadow: 0 2px 8px rgba(67,97,238,0.3);
}

.icon-btn {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    border: none;
    background: var(--bg-tertiary);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.icon-btn:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-2px);
}

/* ইনপুট গ্রুপ */
.input-group {
    margin-bottom: 20px;
}

.input-label {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.input-label i {
    color: var(--primary);
}

select, input {
    width: 100%;
    padding: 14px 18px;
    border: 1.5px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: 1rem;
    font-family: inherit;
    background: var(--input-bg);
    color: var(--text-primary);
    transition: var(--transition);
    cursor: pointer;
}

select:hover, input:hover {
    border-color: var(--primary);
}

select:focus, input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67,97,238,0.2);
}

/* সুয়াপ বাটন */
.swap-btn {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border: none;
    border-radius: var(--border-radius-sm);
    color: white;
    font-weight: 700;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    margin: 8px 0 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.swap-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(67,97,238,0.4);
}

/* ফলাফল সেকশন */
.result-section {
    background: linear-gradient(135deg, var(--bg-tertiary), var(--bg-secondary));
    border-radius: var(--border-radius);
    padding: 20px;
    margin-top: 8px;
    border: 1px solid var(--border-color);
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 10px;
}

.result-header span {
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.result-actions {
    display: flex;
    gap: 8px;
}

.small-btn {
    padding: 6px 12px;
    background: rgba(67,97,238,0.15);
    border: none;
    border-radius: 30px;
    color: var(--primary);
    font-size: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 5px;
    font-weight: 500;
}

.small-btn:hover {
    background: var(--primary);
    color: white;
}

.result-content {
    background: var(--bg-primary);
    border-radius: var(--border-radius-sm);
    padding: 18px;
    font-family: 'Monaco', 'Menlo', monospace;
    font-size: 0.9rem;
    line-height: 1.7;
    max-height: 350px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
}

/* প্রিসিশন কন্ট্রোল */
.precision-row {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 12px;
    margin-top: 16px;
    padding-top: 12px;
    border-top: 1px solid var(--border-color);
}

.precision-row label {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

#precision {
    width: 70px;
    padding: 6px 10px;
    border-radius: 20px;
    font-size: 0.8rem;
}

/* ইতিহাস প্যানেল */
.history-panel {
    margin-top: 16px;
    background: var(--bg-primary);
    border-radius: var(--border-radius-sm);
    padding: 12px;
    display: none;
    border: 1px solid var(--border-color);
}

.history-panel.show {
    display: block;
    animation: slideDown 0.3s ease;
}

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

.history-item {
    padding: 8px 12px;
    margin-bottom: 6px;
    background: var(--bg-tertiary);
    border-radius: 10px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: var(--transition);
}

.history-item:hover {
    background: var(--primary);
    color: white;
    transform: translateX(4px);
}

/* এরর মেসেজ */
.error-message {
    background: rgba(220,38,38,0.1);
    border-left: 3px solid var(--danger);
    padding: 10px 15px;
    border-radius: 10px;
    margin-top: 12px;
    display: none;
    align-items: center;
    gap: 10px;
    font-size: 0.8rem;
    color: var(--danger);
}

/* ফুটার */
.footer {
    text-align: center;
    margin-top: 24px;
    padding: 20px;
    color: var(--text-secondary);
    font-size: 0.75rem;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 15px;
    flex-wrap: wrap;
}

.social-links a {
    color: var(--text-secondary);
    font-size: 1.3rem;
    transition: var(--transition);
}

.social-links a:hover {
    color: var(--primary);
    transform: translateY(-3px);
}

/* রেস্পন্সিভ */
@media (max-width: 550px) {
    body {
        padding: 16px;
    }
    .converter-card {
        padding: 20px;
    }
    h1 {
        font-size: 1.4rem;
    }
    .mode-btn {
        padding: 6px 10px;
        font-size: 0.7rem;
    }
    .mode-btn i {
        font-size: 0.8rem;
    }
    .logo-wrapper {
        width: 55px;
        height: 55px;
    }
    .logo-wrapper i {
        font-size: 26px;
    }
}