:root {
    /* Black, White, and Teal Palette */
    --bg-base: #F5F5F7;
    --card-bg: #FFFFFF;
    --card-shadow: 0 24px 48px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.02);
    --card-border: 1px solid rgba(255,255,255,0.8);
    --input-bg: #F0F0F3;
    --input-border: 1px solid transparent;
    --input-shadow: inset 0 2px 4px rgba(0,0,0,0.02);
    --text-main: #000000;
    --text-muted: #86868B;
    --grad-primary: linear-gradient(135deg, #00C4B8, #00A59B);
    --grad-primary-shadow: rgba(0,165,155,0.3);
    --grad-result: linear-gradient(135deg, #E8F7F6 0%, #D0EFEF 100%);
    --result-text: #000000;
    --result-label: rgba(0,0,0,0.5);
}

html.dark-mode, body.dark-mode {
    --bg-base: #000000;
    --card-bg: #1C1C1E;
    --card-shadow: 0 24px 48px rgba(0,0,0,0.4), 0 0 0 1px rgba(255,255,255,0.05);
    --card-border: 1px solid rgba(255,255,255,0.05);
    --input-bg: #2C2C2E;
    --input-border: 1px solid rgba(255,255,255,0.05);
    --input-shadow: inset 0 2px 4px rgba(0,0,0,0.2);
    --text-main: #FFFFFF;
    --text-muted: #86868B;
    --grad-primary: linear-gradient(135deg, #00D4C8, #00A59B);
    --grad-primary-shadow: rgba(0,165,155,0.2);
    --grad-result: linear-gradient(135deg, #112A28 0%, #0A1A18 100%);
    --result-text: #FFFFFF;
    --result-label: rgba(255,255,255,0.6);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: "SF Pro Display", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
    transition: background-color 0.4s ease, color 0.4s ease, box-shadow 0.4s ease;
}

body {
    background-color: var(--bg-base);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: var(--text-main);
    padding: 20px;
    position: relative;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: fixed;
    top: -15%;
    left: -10%;
    width: 70vw;
    height: 70vw;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(255,255,255,0.8) 0%, rgba(255,255,255,0) 70%);
    z-index: -1;
    pointer-events: none;
}

html.dark-mode body::before {
    background: radial-gradient(circle, rgba(255,255,255,0.05) 0%, rgba(255,255,255,0) 70%);
}

.glass-card {
    width: 100%;
    max-width: 420px;
    padding: 40px 32px;
    background: var(--card-bg);
    border: var(--card-border);
    border-radius: 36px;
    box-shadow: var(--card-shadow);
    position: relative;
    z-index: 10;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 35px;
}

.title-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

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

.app-logo {
    width: 36px;
    height: 36px;
    object-fit: contain;
}

h2 {
    font-weight: 700;
    font-size: 24px;
    letter-spacing: -0.6px;
    color: var(--text-main);
    line-height: 1.1;
}

.icon-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: none;
    background: var(--input-bg);
    color: var(--text-main);
    font-size: 16px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
    flex-shrink: 0;
    transition: transform 0.2s ease;
}

.icon-btn:active { transform: scale(0.92); }

.bw-icon {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    border: 2px solid var(--text-main);
    background: linear-gradient(90deg, var(--text-main) 50%, transparent 50%);
    transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

html.dark-mode .bw-icon { transform: rotate(180deg); }

.input-group {
    margin-bottom: 22px;
    position: relative;
}

.input-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
    padding: 0 6px;
}

.input-group label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-muted);
    letter-spacing: -0.2px;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    width: 100%;
    background: var(--input-bg);
    border-radius: 16px;
    box-shadow: var(--input-shadow);
    border: var(--input-border);
    padding-left: 20px;
    transition: all 0.2s ease;
}

.input-wrapper:focus-within {
    background: var(--card-bg);
    border-color: #00A59B;
    box-shadow: 0 0 0 4px rgba(0,165,155,0.15);
}

.input-symbol {
    font-size: 16px;
    font-weight: 600;
    color: #00A59B;
    margin-right: 4px;
    flex-shrink: 0;
    pointer-events: none;
}

html.dark-mode .input-symbol { color: #00C4B8; }

input[type="text"], input[type="number"], select {
    width: 100%;
    padding: 16px 20px;
    border: var(--input-border);
    background: var(--input-bg);
    border-radius: 16px;
    font-size: 16px;
    font-weight: 500;
    color: var(--text-main);
    box-shadow: var(--input-shadow);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
    transition: all 0.2s ease;
}

input[type="text"]#amount {
    flex: 1;
    min-width: 0;
    background: transparent !important;
    box-shadow: none !important;
    border: none !important;
    padding-left: 0;
    padding-right: 75px;
}

input[type="text"]::placeholder, input[type="number"]::placeholder {
    color: var(--text-muted);
    opacity: 0.5;
}

select:focus {
    background: var(--card-bg);
    border-color: #00A59B;
    box-shadow: 0 0 0 4px rgba(0,165,155,0.15);
}

.inner-input-btn {
    position: absolute;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s ease, transform 0.2s ease;
    opacity: 0.6;
    z-index: 2;
}

.inner-input-btn:hover { opacity: 1; color: var(--text-main); }
.inner-input-btn:active { transform: scale(0.85); }

.clear-btn { right: 15px; font-size: 14px; font-weight: bold; }
.calc-icon-btn { right: 42px; }

.select-wrapper { position: relative; }
.select-wrapper::after {
    content: "⌄";
    font-size: 20px;
    color: var(--text-muted);
    position: absolute;
    right: 20px;
    top: 45%;
    transform: translateY(-50%);
    pointer-events: none;
}

.swap-container {
    display: flex;
    justify-content: center;
    margin: -12px 0 10px 0;
    z-index: 2;
    position: relative;
}

.swap-btn {
    width: 44px;
    height: 44px;
    background: var(--card-bg);
    border: 1px solid rgba(0,0,0,0.05);
    box-shadow: 0 4px 12px rgba(0,0,0,0.06), 0 1px 3px rgba(0,0,0,0.04);
}

html.dark-mode .swap-btn { border: 1px solid rgba(255,255,255,0.1); }

.result-box {
    margin-top: 30px;
    padding: 35px 25px;
    border-radius: 28px;
    background: var(--grad-result);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 120px;
    box-shadow: inset 0 2px 10px rgba(255,255,255,0.4), 0 12px 24px rgba(0,0,0,0.06);
    border: 1px solid rgba(255,255,255,0.3);
    position: relative;
    overflow: hidden;
    perspective: 1000px;
}

html.dark-mode .result-box {
    box-shadow: inset 0 2px 10px rgba(255,255,255,0.05), 0 12px 24px rgba(0,0,0,0.2);
    border: 1px solid rgba(255,255,255,0.05);
}

#result-amount {
    font-size: 40px;
    font-weight: 700;
    color: var(--result-text);
    word-wrap: break-word;
    letter-spacing: -1.5px;
    text-align: center;
    transition: transform 0.15s cubic-bezier(0.16, 1, 0.3, 1);
}

.teal-symbol {
    color: #00A59B;
    font-size: 0.65em;
    vertical-align: top;
    position: relative;
    top: 4px;
    margin-right: 4px;
    font-weight: 600;
}

html.dark-mode .teal-symbol { color: #00C4B8; }

/* --- Bank Markup UI --- */
.markup-container {
    position: absolute;
    bottom: 12px;
    right: 16px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.markup-label {
    font-size: 11px;
    font-weight: 600;
    color: #00A59B;
    opacity: 0;
    transform: translateX(10px);
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

html.dark-mode .markup-label { color: #00C4B8; }

.markup-label.visible {
    opacity: 1;
    transform: translateX(0);
}

.markup-toggle {
    background: none;
    border: none;
    color: var(--text-muted);
    opacity: 0.4;
    cursor: pointer;
    padding: 6px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    -webkit-tap-highlight-color: transparent;
}

.markup-toggle:hover { opacity: 0.8; }
.markup-toggle:active { transform: scale(0.9); }

.markup-toggle.active {
    color: #00A59B;
    opacity: 1;
    background: rgba(0, 165, 155, 0.15);
}

html.dark-mode .markup-toggle.active {
    color: #00C4B8;
    background: rgba(0, 196, 184, 0.2);
}

/* --- Pulse Attention Animation --- */
@keyframes pulseRing {
    0% { box-shadow: 0 0 0 0 rgba(0, 165, 155, 0.5); }
    70% { box-shadow: 0 0 0 10px rgba(0, 165, 155, 0); }
    100% { box-shadow: 0 0 0 0 rgba(0, 165, 155, 0); }
}

@keyframes pulseRingDark {
    0% { box-shadow: 0 0 0 0 rgba(0, 196, 184, 0.5); }
    70% { box-shadow: 0 0 0 10px rgba(0, 196, 184, 0); }
    100% { box-shadow: 0 0 0 0 rgba(0, 196, 184, 0); }
}

.pulse-attention {
    animation: pulseRing 2s infinite cubic-bezier(0.16, 1, 0.3, 1);
    color: #00A59B !important;
    opacity: 0.8 !important;
}

html.dark-mode .pulse-attention {
    animation: pulseRingDark 2s infinite cubic-bezier(0.16, 1, 0.3, 1);
    color: #00C4B8 !important;
}

.footer-controls {
    margin-top: 25px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.primary-btn {
    width: 100%;
    padding: 18px;
    border: none;
    outline: none;
    background: var(--grad-primary);
    color: #FFFFFF;
    font-size: 16px;
    font-weight: 600;
    border-radius: 100px;
    cursor: pointer;
    box-shadow: 0 8px 24px var(--grad-primary-shadow), inset 0 1px 2px rgba(255,255,255,0.5);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    letter-spacing: -0.3px;
    flex-shrink: 0;
}

.primary-btn:active {
    transform: scale(0.98);
    box-shadow: 0 4px 12px var(--grad-primary-shadow);
}

.status {
    font-size: 12px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 6px;
    font-weight: 500;
}

.status-dot {
    width: 8px;
    height: 8px;
    background-color: #34C759;
    border-radius: 50%;
    box-shadow: 0 0 8px rgba(52,199,89,0.4);
    transition: background-color 0.2s, box-shadow 0.2s;
}

.status-dot.offline {
    background-color: #FF3B30;
    box-shadow: 0 0 8px rgba(255,59,48,0.4);
}

.interactive-status {
    cursor: pointer;
    padding: 8px 12px;
    transition: color 0.2s ease, transform 0.2s ease;
}

.interactive-status:hover { color: #00A59B; }
html.dark-mode .interactive-status:hover { color: #00C4B8; }

.interactive-status:hover .status-dot {
    background-color: #00A59B;
    box-shadow: 0 0 8px rgba(0,165,155,0.4);
}

html.dark-mode .interactive-status:hover .status-dot {
    background-color: #00C4B8;
    box-shadow: 0 0 8px rgba(0,196,184,0.4);
}

.interactive-status:active { transform: scale(0.96) translateY(1px); }

.refresh-icon {
    font-size: 14px;
    margin-left: 4px;
    display: inline-block;
    transition: transform 0.3s ease;
}

.interactive-status:hover .refresh-icon { transform: rotate(90deg); }

/* --- Footer Layout --- */
.footer-credits {
    margin-top: 32px;
    width: 100%;
    max-width: 420px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 10px;
    color: var(--text-muted);
    font-weight: 500;
    z-index: 10;
    padding: 0 4px;
}

.social-links {
    display: flex;
    gap: 16px;
}

.social-links a {
    color: var(--text-muted);
    transition: color 0.3s ease, transform 0.2s ease;
    display: flex;
    align-items: center;
    opacity: 0.7;
}

.social-links a:hover {
    color: #00A59B;
    transform: translateY(-2px);
    opacity: 1;
}

html.dark-mode .social-links a:hover {
    color: #00C4B8;
}

/* iOS Install Prompt */
.ios-prompt {
    display: none;
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    width: 90%;
    max-width: 380px;
    padding: 24px;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border: 1px solid rgba(0,0,0,0.05);
    border-radius: 28px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
    z-index: 1000;
    text-align: left;
    animation: slideUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

html.dark-mode .ios-prompt {
    background: rgba(28,28,30,0.85);
    border: 1px solid rgba(255,255,255,0.05);
}

@keyframes slideUp {
    from { opacity: 0; transform: translate(-50%, 40px) scale(0.95); }
    to { opacity: 1; transform: translate(-50%, 0) scale(1); }
}

.ios-prompt-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.ios-prompt-title { font-weight: 700; font-size: 16px; color: var(--text-main); }

.ios-prompt-close {
    background: var(--input-bg);
    border: none;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-muted);
}

.ios-prompt-body { font-size: 14px; color: var(--text-muted); line-height: 1.5; }

.ios-prompt-icon {
    display: inline-block;
    background: var(--input-bg);
    padding: 4px 8px;
    border-radius: 8px;
    font-weight: 600;
    color: var(--text-main);
    margin: 0 2px;
}

/* Toast Notification */
.toast-notification {
    position: fixed;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    background: rgba(0, 0, 0, 0.8);
    color: #FFFFFF;
    padding: 12px 24px;
    border-radius: 100px;
    font-size: 14px;
    font-weight: 500;
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    z-index: 3000;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.toast-notification.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

html.dark-mode .toast-notification {
    background: rgba(255, 255, 255, 0.9);
    color: #000000;
}

/* Calculator Modal */
.calc-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.15);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 2000;
    justify-content: center;
    align-items: center;
    padding: 20px;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.calc-overlay.active { display: flex; opacity: 1; }

.calc-modal {
    width: 100%;
    max-width: 420px;
    padding: 40px 32px;
    background: var(--card-bg);
    border: var(--card-border);
    border-radius: 36px;
    box-shadow: var(--card-shadow);
    transform: scale(0.95) translateY(20px);
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    display: flex;
    flex-direction: column;
}

.calc-overlay.active .calc-modal { transform: scale(1) translateY(0); }

.calc-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-shrink: 0;
}

.calc-header h3 { font-size: 18px; font-weight: 700; color: var(--text-main); }

.calc-screen {
    width: 100%;
    background: var(--input-bg);
    border-radius: 20px;
    padding: 16px 20px;
    text-align: right;
    box-shadow: var(--input-shadow);
    margin-bottom: 24px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    min-height: 96px;
    flex-shrink: 0;
}

.calc-history {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-muted);
    min-height: 22px;
    margin-bottom: 4px;
    overflow-x: auto;
    white-space: nowrap;
}

.calc-display {
    font-size: 36px;
    font-weight: 500;
    color: var(--text-main);
    overflow-x: auto;
    white-space: nowrap;
}

.calc-op-display { color: #00A59B; }
html.dark-mode .calc-op-display { color: #00C4B8; }

.calc-keys {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(5, 1fr);
    gap: 12px;
    margin-bottom: 20px;
    flex-grow: 1;
}

.calc-key {
    background: var(--input-bg);
    border: none;
    border-radius: 100px;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
    font-weight: 500;
    color: var(--text-main);
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0,0,0,0.02);
    transition: transform 0.1s, background 0.2s, opacity 0.1s, filter 0.1s, box-shadow 0.1s;
    -webkit-user-select: none;
    user-select: none;
    -webkit-touch-callout: none;
}

.calc-key.operator {
    color: #00A59B;
    background: rgba(0,165,155,0.08);
}

html.dark-mode .calc-key.operator {
    color: #00C4B8;
    background: rgba(0,165,155,0.15);
}

.calc-key:active {
    transform: scale(0.92);
    opacity: 0.8;
    filter: brightness(0.9);
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.05);
}

html.dark-mode .calc-key:active {
    filter: brightness(1.2);
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.2);
}

.calc-key.equals {
    grid-column: span 2;
    background: var(--text-main);
    color: var(--card-bg);
    font-weight: 600;
}

.calc-key.top-mod { font-size: 15px; }